Yocto-maxirelay : user's guide

Yocto-MaxiRelay : User's guide

1. Introduction
1.1 Prerequisites
1.2 Optional accessories
2. Presentation
2.1 Common elements
2.2 Specific elements
3. Electrocution hazards
3.1 Dangerous components
4. First steps
4.1 Localization
4.2 Test of the module
4.3 Configuration
5. Assembly and connections
5.1 Fixing
5.2 Assembly examples
5.3 Electro-magnetic relays and coils
5.4 USB power distribution
6. Programming, general concepts
6.1 Programming paradigm
6.2 The Yocto-MaxiRelay module
6.3 Module control interface
6.4 Relay function interface
6.5 What interface: Native, DLL or Service ?
6.6 Programming, where to start?
7. Using the Yocto-MaxiRelay in command line
7.1 Installing
7.2 Use: general description
7.3 Control of the Relay function
7.4 Control of the module part
7.5 Limitations
8. Using Yocto-MaxiRelay with Javascript
8.1 Getting ready
8.2 Control of the Relay function
8.3 Control of the module part
8.4 Error handling
9. Using Yocto-MaxiRelay with PHP
9.1 Getting ready
9.2 Control of the Relay function
9.3 Control of the module part
9.4 HTTP callback API and NAT filters
9.5 Error handling
10. Using Yocto-MaxiRelay with C++
10.1 Control of the Relay function
10.2 Control of the module part
10.3 Error handling
10.4 Integration variants for the C++ Yoctopuce library
11. Using Yocto-MaxiRelay with Objective-C
11.1 Control of the Relay function
11.2 Control of the module part
11.3 Error handling
12. Using Yocto-MaxiRelay with Visual Basic .NET
12.1 Installation
12.2 Using the Yoctopuce API in a Visual Basic project
12.3 Control of the Relay function
12.4 Control of the module part
12.5 Error handling
13. Using Yocto-MaxiRelay with C#
13.1 Installation
13.2 Using the Yoctopuce API in a Visual C# project
13.3 Control of the Relay function
13.4 Control of the module part
13.5 Error handling
14. Using Yocto-MaxiRelay with Delphi
14.1 Preparation
14.2 Control of the Relay function
14.3 Control of the module part
14.4 Error handling
15. Using the Yocto-MaxiRelay with Python
15.1 Source files
15.2 Dynamic library
15.3 Control of the Relay function
15.4 Control of the module part
15.5 Error handling
16. Using the Yocto-MaxiRelay with Java
16.1 Getting ready
16.2 Control of the Relay function
16.3 Control of the module part
16.4 Error handling
17. Using the Yocto-MaxiRelay with Android
17.1 Native access and VirtualHub
17.2 Getting ready
17.3 Compatibility
17.4 Activating the USB port under Android
17.5 Control of the Relay function
17.6 Control of the module part
17.7 Error handling
18. Advanced programming
18.1 Event programming
19. Using with unsupported languages
19.1 Command line
19.2 VirtualHub and HTTP GET
19.3 Using dynamic libraries
19.4 Porting the high level library
20. High-level API Reference
20.1 General functions
20.2 Module control interface
20.3 Relay function interface
21. Troubleshooting
21.1 Linux and USB
21.2 ARM Platforms: HF and EL
22. Characteristics
23. Index

1. Introduction

The Yocto-MaxiRelay module is a 69x58mm module which allows you to control relays by USB. These relays can commute up to 250V and 6A. This allows you to pilot numerous equipments by acting directly on their power supply. The module small dimensions enable it to be slipped almost anywhere, including inside the piloted equipment.


The Yocto-MaxiRelay module

Yoctopuce thanks you for buying this Yocto-MaxiRelay and sincerely hopes that you will be satisfied with it. The Yoctopuce engineers have put a large amount of effort to ensure that your Yocto-MaxiRelay is easy to install anywhere and easy to drive from a maximum of programming languages. If you are nevertheless disappointed with this module, do not hesitate to contact Yoctopuce support1.

By design, all Yoctopuce modules are driven the same way. Therefore, user's guides for all the modules of the range are very similar. If you have already carefully read through the user's guide of another Yoctopuce module, you can jump directly to the description of the module functions.

1.1. Prerequisites

In order to use your Yocto-MaxiRelay module, you should have the following items at hand.

A computer

Yoctopuce modules are intended to be driven by a computer (or possibly an embedded microprocessor). You will write the control software yourself, according to your needs, using the information provided in this manual.

Yoctopuce provides software libraries to drive its modules for the following operating systems: Windows, Mac OS X, Linux, and Android. Yoctopuce modules do not require installing any specific system driver, as they leverage the standard HID driver2 provided with every operating system.

Windows versions currently supported are: Windows XP, Windows 2003, Windows Vista, and Windows 7. Both 32 bit and 64 bit versions are supported. Yoctopuce is frequently testing its modules on Windows XP and Windows 7.

Mac OS X versions currently supported are: 10.6 (Snow Leopard), Mac OS X 10.7 (Lion), and 10.8 (Mountain Lion). Yoctopuce is frequently testing its modules on Mac OS X 10.6 and 10.7.

Linux kernels currently supported are the 2.6 branch and the 3.0 branch. Other versions of the Linux kernel, and even other UNIX variants, are very likely to work as well, as Linux support is implemented through the standard libusb API. Yoctopuce is frequently testing its modules on Linux kernel 2.6.

Android versions currently supported are: Android 3.1 and later. Moreover, it is necessary for the tablet or phone to support the Host USB mode. Yoctopuce is frequently testing its modules on Android 4.x on a Nexus 7 and a Samsung Galaxy S3 with the Java for Android library.

A USB cable, type A-micro B

USB connectors exist in three sizes: the "standard" size that you probably use to connect your printer, the very common mini size to connect small devices, and finally the micro size often used to connect mobile phones, as long as they do not exhibit an apple logo. All USB modules manufactured by Yoctopuce use micro size connectors.


The most common USB 2 connectors: A, B, Mini B, Micro A, Micro B.3

To connect your Yocto-MaxiRelay module to a computer, you need a USB cable of type A-micro B. The price of this cable may vary a lot depending on the source, look for it under the name USB A to micro B Data cable. Make sure not to buy a simple USB charging cable without data connectivity. The correct type of cable is available on the Yoctopuce shop.


You must plug in your Yocto-MaxiRelay module with a USB cable of type A - micro B.

If you insert a USB hub between the computer and the Yocto-MaxiRelay module, make sure to take into account the USB current limits. If you do not, be prepared to face unstable behaviors and unpredictable failures. You can find more details on this topic in the chapter about assembly and connections.

1.2. Optional accessories

The accessories below are not necessary to use the Yocto-MaxiRelay module but might be useful depending on your project. These are mostly common products that you can buy from your favourite hacking store. To save you the tedious job of looking for them, most of them are also available on the Yoctopuce shop.

Screws and spacers

In order to mount the Yocto-MaxiRelay module, you can put small screws in the 3mm assembly holes, with a screw head no larger than 8mm. The best way is to use threaded spacers, which you can then mount wherever you want. You can find more details on this topic in the chapter about assembly and connections.

Micro-USB hub

If you intend to put several Yoctopuce modules in a very small space, you can connect them directly to a micro-USB hub. Yoctopuce builds a USB hub particularly small for this purpose (down to 20mmx36mm), on which you can directly solder a USB cable instead of using a USB plug. For more details, see the micro-USB hub information sheet.

YoctoHub-Ethernet and YoctoHub-Wireless

You can add network connectivity to your Yocto-MaxiRelay, thanks to the YoctoHub-Ethernet and the YoctoHub-Wireless. The YoctoHub-Ethernet provides Ethernet connectivity and the YoctoHub-Wireless provides WiFi connectivity. Both can drive up to three devices and behave exactly like a regular computer running a VirtualHub.

Solid copper ribbon cable

If you wish to solder the Yocto-MaxiRelay module directly to a micro-USB hub to save on the space used by USB cables, consider using solid copper ribbon cable: it is much easier to solder. In any case, you will need cable with 4 wires with 1.27mm pitch.

2. Presentation


1:USB socket 4:State led for relay 1
2:Yocto-button 5:State led for relay 2
3:Yocto-led 6:Relay 1 terminal
7:Relay 2 terminal

2.1. Common elements

All Yocto-modules share a number of common functionalities.

USB connector

Yoctopuce modules all come with a micro-B USB socket. The corresponding cables are not the most common, but the sockets are the smallest available.

Warning: the USB connector is simply soldered in surface and can be pulled out if the USB plug acts as a lever. In this case, if the tracks stayed in position, the connector can be soldered back with a good iron and using flux to avoid bridges. Alternatively, you can solder a USB cable directly in the 1.27mm-spaced holes near the connector.

Yocto-button

The Yocto-button has two functionalities. First, it can activate the Yocto-beacon mode (see below under Yocto-led). Second, if you plug in a Yocto-module while keeping this button pressed, you can then reprogram its firmware with a new version. Note that there is a simpler UI-based method to update the firmware, but this one works even in case of severely damaged firmware.

Yocto-led

Normally, the Yocto-led is used to indicate that the module is working smoothly. The Yocto-led then emits a low blue light which varies slowly, mimicking breathing. The Yocto-led stops breathing when the module is not communicating any more, as for instance when powered by a USB hub which is disconnected from any active computer.

When you press the Yocto-button, the Yocto-led switches to Yocto-beacon mode. It starts flashing faster with a stronger light, in order to facilitate the localization of a module when you have several identical ones. It is indeed possible to trigger off the Yocto-beacon by software, as it is possible to detect by software that a Yocto-beacon is on.

The Yocto-led has a third functionality, which is less pleasant: when the internal software which controls the module encounters a fatal error, the Yocto-led starts emitting an SOS in morse 4. If this happens, unplug and re-plug the module. If it happens again, check that the module contains the latest version of the firmware, and, if it is the case, contact Yoctopuce support5.

Current sensor

Each Yocto-module is able to measure its own current consumption on the USB bus. Current supply on a USB bus being quite critical, this functionality can be of great help. You can only view the current consumption of a module by software.

Serial number

Each Yocto-module has a unique serial number assigned to it at the factory. For Yocto-MaxiRelay modules, this number starts with HI8PWER1. The module can be software driven using this serial number. The serial number cannot be modified.

Logical name

The logical name is similar to the serial number: it is a supposedly unique character string which allows you to reference your module by software. However, in the opposite of the serial number, the logical name can be modified at will. The benefit is to enable you to build several copies of the same project without needing to modify the driving software. You only need to program the same logical name in each copy. Warning: the behavior of a project becomes unpredictable when it contains several modules with the same logical name and when the driving software tries to access one of these modules through its logical name. When leaving the factory, modules do not have an assigned logical name. It is yours to define.

2.2. Specific elements

Screw terminal

The eight relays embedded in the Yocto-MaxiRelay module function as simple commutators. It means that when they are at rest (state A), the commanded circuit is open; when the relay is active (state B), the circuit is closed.


Relay wiring inside the module.

Leds indicating the active output

Right in front of the relays, there is a group of eight green leds which indicate which relay is active. By default, the light of these leds is rather strong, but you can change their luminosity by software.

3. Electrocution hazards

While the Yocto-MaxiRelay module is perfectly able to manage a 250V voltage, we strongly discourage you to work on a voltage high enough to present risks. Nevertheless, if you decide to override this advice, respect these recommendations, they may well protect you from an embarrassing nomination to the Darwin Awards.

3.1. Dangerous components

Some components of the Yocto-MaxiRelay module find themselves directly on the relay working tension. Make sure to never touch them when the module is powered on. These components must never be in contact with a conductive component of your project (look out for metallic enclosures). Even more important, make sure that your project end user can never touch these components, even accidentally.


Potentially dangerous components of the Yocto-MaxiRelay module

4. First steps

When reading this chapter, your Yocto-MaxiRelay should be connected to your computer, which should have recognized it. It is time to make it work.

Go to the Yoctopuce web site and download the Virtual Hub software6. It is available for Windows, Linux, and Mac OS X. Normally, the Virtual Hub software serves as an abstraction layer for languages which cannot access the hardware layers of your computer. However, it also offers a succinct interface to configure your modules and to test their basic functions. You access this interface with a simple web browser7. Start the Virtual Hub software in a command line, open your preferred web browser and enter the URL http://127.0.0.1:4444. The list of the Yoctopuce modules connected to your computer is displayed.


Module list as displayed in your web bowser.

4.1. Localization

You can then physically localize each of the displayed modules by clicking on the beacon button. This puts the Yocto-led of the corresponding module in Yocto-beacon mode. It starts flashing, which allows you to easily localize it. The second effect is to display a little blue circle on the screen. You obtain the same behavior when pressing the Yocto-button of the module.

4.2. Test of the module

The first item to check is that your module is working well: click on the serial number corresponding to your module. This displays a window summarizing the properties of your Yocto-MaxiRelay.


Properties of the Yocto-MaxiRelay module.

This window allows you, among other things, to test the relays with the switch to A / switch to B buttons. There is a characteristic clicking when a relay is working. Moreover, the led corresponding to the active output lights up. Notice that the module consumption varies according to the active outputs.

4.3. Configuration

When, in the module list, you click on the configure button corresponding to your module, the configuration window is displayed.


Yocto-MaxiRelay module configuration.

Firmware

The module firmware can easily be updated with the help of the interface. To do so, you must beforehand have the adequate firmware on your local disk. Firmware destined for Yoctopuce modules are available as .byn files and can be downloaded from the Yoctopuce web site.

To update a firmware, simply click on the upgrade button on the configuration window and follow the instructions. If the update fails for one reason or another, unplug and re-plug the module and start the update process again. This solves the issue in most cases. If the module was unplugged while it was being reprogrammed, it does probably not work anymore and is not listed in the interface. However, it is always possible to reprogram the module correctly by using the Virtual Hub software 8 in command line 9.

Logical name of the module

The logical name is a name that you choose, which allows you to access your module, in the same way a file name allows you to access its content. A logical name has a maximum length of 19 characters. Authorized characters are A..Z, a..z, 0..9, _, and -. If you assign the same logical name to two modules connected to the same computer and you try to access one of them through this logical name, behavior is undetermined: you have no way of knowing which of the two modules answers.

Luminosity

This parameter allows you to act on the maximal intensity of the leds of the module. This enables you, if necessary, to make it a little more discreet, while limiting its power consumption. Note that this parameter acts on all the signposting leds of the module, including the Yocto-led. If you connect a module and no led turns on, it may mean that its luminosity was set to zero.

Logical names of functions

Each Yoctopuce module has a serial number and a logical name. In the same way, each function on each Yoctopuce module has a hardware name and a logical name, the latter can be freely chosen by the user. Using logical names for functions provides a greater flexibility when programming modules.

The only functions of the Yocto-MaxiRelay module correspond to its embedded relays, with hardware names "relay1" to "relay8".

5. Assembly and connections

This chapter provides important information regarding the use of the Yocto-MaxiRelay module in real-world situations. Make sure to read it carefully before going too far into your project if you want to avoid pitfalls.

5.1. Fixing

While developing your project, you can simply let the module hang at the end of its cable. Check only that it does not come in contact with any conducting material (such as your tools). When your project is almost at an end, you need to find a way for your modules to stop moving around.


Examples of assembly on supports

The Yocto-MaxiRelay module contains 3mm assembly holes. You can use these holes for screws. The screw head diameter must not be larger than 8mm or they will damage the module circuits. Make sure that the lower surface of the module is not in contact with the support. We recommend using spacers, but other methods are possible. Nothing prevents you from fixing the module with a glue gun; it will not be good-looking, but it will hold.

5.2. Assembly examples

If you obtained this Yocto-MaxiRelay module, it is probably because you know exactly what you intend to do with it. You can nevertheless find below a few wiring examples, among the simplest.


Pilot a light bulb with your Yocto-MaxiRelay module.


Pilot two light bulbs with your Yocto-MaxiRelay module.

5.3. Electro-magnetic relays and coils

Some devices that you may wish to control with your Yocto-MaxiRelay module contain large coils. It is in particular the case for electric motors and transformers. This may cause trouble because of the auto-induction generated when current goes through a coil. A very high voltage briefly appears at the ends of a coil when when one brutally cuts the current passing through it. This high voltage can create an electric arc where the circuit was cut, in our case inside the relay soldered on the module. This electric arc can eat away the relay connections, leading to premature aging.
Therefore, we advise against controlling electric motors or transformers with an electro-magnetic relay, be it a Yocto-MaxiRelay module, or any other command system based on this technology.
It is possible to limit this phenomenon by inserting a TVS diode in parallel with the device containing the coil. These diodes are blocking below a specified voltage, and conductive beyond. So if you clamp one of theses diode on your inductive load, this will short cut voltage peaks. You only have to choose a diode with the right clamping voltage for your application. If you wish to know more, Tyco published an application note about this 10.


Controlling an electric motor with a relay, using a protecting diode.

5.4. USB power distribution

Although USB means Universal Serial BUS, USB devices are not physically organized as a flat bus but as a tree, using point-to-point connections. This has consequences on power distribution: to make it simple, every USB port must supply power to all devices directly or indirectly connected to it. And USB puts some limits.

In theory, a USB port provides 100mA, and may provide up to 500mA if available and requested by the device. In the case of a hub without external power supply, 100mA are available for the hub itself, and the hub should distribute no more than 100mA to each of its ports. This is it, and this is not much. In particular, it means that in theory, it is not possible to connect USB devices through two cascaded hubs without external power supply. In order to cascade hubs, it is necessary to use self-powered USB hubs, that provide a full 500mA to each subport.

In practice, USB would not have been as successful if it was really so picky about power distribution. As it happens, most USB hub manufacturers have been doing savings by not implementing current limitation on ports: they simply connect the computer power supply to every port, and declare themselves as self-powered hub even when they are taking all their power from the USB bus (in order to prevent any power consumption check in the operating system). This looks a bit dirty, but given the fact that computer USB ports are usually well protected by a hardware current limitation around 2000mA, it actually works in every day life, and seldom makes hardware damage.

What you should remember: if you connect Yoctopuce modules through one, or more, USB hub without external power supply, you have no safe-guard and you depend entirely on your computer manufacturer attention to provide as much current as possible on the USB ports, and to detect overloads before they lead to problems or to hardware damages. When modules are not provided enough current, they may work erratically and create unpredictable bugs. If you want to prevent any risk, do not cascade hubs without external power supply, and do not connect peripherals requiring more than 100mA behind a bus-powered hub.

In order to help controlling and planning overall power consumption for your project, all Yoctopuce modules include a built-in current sensor that tells (with 5mA precision) the consumption of the module on the USB bus.

6. Programming, general concepts

The Yoctopuce API was designed to be at the same time simple to use and sufficiently generic for the concepts used to be valid for all the modules in the Yoctopuce range, and this in all the available programming languages. Therefore, when you have understood how to drive your Yocto-MaxiRelay with your favorite programming language, learning to use another module, even with a different language, will most likely take you only a minimum of time.

6.1. Programming paradigm

The Yoctopuce API is object oriented. However, for simplicity's sake, only the basics of object programming were used. Even if you are not familiar with object programming, it is unlikely that this will be a hinderance for using Yoctopuce products. Note that you will never need to allocate or deallocate an object linked to the Yoctopuce API: it is automatically managed.

There is one class per Yoctopuce function type. The name of these classes always starts with a Y followed by the name of the function, for example YTemperature, YRelay, YPressure, etc.. There is also a YModule class, dedicated to managing the modules themselves, and finally there is the static YAPI class, that supervises the global workings of the API and manages low level communications.


Structure of the Yoctopuce API.

In the Yoctopuce API, priority was put on the ease of access to the module functions by offering the possibility to make abstractions of the modules implementing them. Therefore, it is quite possible to work with a set of functions without ever knowing exactly which module are hosting them at the hardware level. This tremendously simplifies programming projects with a large number of modules.

From the programming stand point, your Yocto-MaxiRelay is viewed as a module hosting a given number of functions. In the API, these functions are objects which can be found independently, in several ways.

Access to the functions of a module

Access by logical name

Each function can be assigned an arbitrary and persistent logical name: this logical name is stored in the flash memory of the module, even if this module is disconnected. An object corresponding to an Xxx function to which a logical name has been assigned can then be directly found with this logical name and the YXxx.FindXxx method. Note however that a logical name must be unique among all the connected modules.

Access by enumeration

You can enumerate all the functions of the same type on all the connected modules with the help of the classic enumeration functions FirstXxx and nextXxxx available for each YXxx class.

Access by hardware name

Each module function has a hardware name, assigned at the factory and which cannot be modified. The functions of a module can also be found directly with this hardware name and the YXxx.FindXxx function of the corresponding class.

Difference between Find and First

The YXxx.FindXxxx and YXxx.FirstXxxx methods do not work exactly the same way. If there is no available module, YXxx.FirstXxxx returns a null value. On the opposite, even if there is no corresponding module, YXxx.FindXxxx returns a valid object, which is not online but which could become so if the corresponding module is later connected.

Function handling

When the object corresponding to a function is found, its methods are available in a classic way. Note that most of these subfunctions require the module hosting the function to be connected in order to be handled. This is generally not guaranteed, as a USB module can be disconnected after the control software has started. The isOnline method, available in all the classes, is then very helpful.

Access to the modules

Even if it is perfectly possible to build a complete project while making a total abstraction of which function is hosted on which module, the modules themselves are also accessible from the API. In fact, they can be handled in a way quite similar to the functions. They are assigned a serial number at the factory which allows you to find the corresponding object with YModule.Find(). You can also assign arbitrary logical names to the modules to make finding them easier. Finally, the YModule class contains the YModule.FirstModule() and nextModule() enumeration methods allowing you to list the connected modules.

Functions/Module interaction

From the API standpoint, the modules and their functions are strongly uncorrelated by design. Nevertheless, the API provides the possibility to go from one to the other. Thus, the get_module() method, available for each function class, allows you to find the object corresponding to the module hosting this function. Inversely, the YModule class provides several methods allowing you to enumerate the functions available on a module.

6.2. The Yocto-MaxiRelay module

The Yocto-MaxiRelay module provides eight instances of the Relay function, corresponding to the eight relays present on the module.

module : Module

attributetypemodifiable ?
productName  String  read-only
serialNumber  String  read-only
logicalName  String  modifiable
productId  Hexadecimal number  read-only
productRelease  Hexadecimal number  read-only
firmwareRelease  String  read-only
persistentSettings  Enumerated  modifiable
luminosity  0..100%  modifiable
beacon  On/Off  modifiable
upTime  Time  read-only
usbCurrent  Used current (mA)  read-only
rebootCountdown  Integer  modifiable
usbBandwidth  Enumerated  modifiable

relay1 : Relay
relay2 : Relay
relay3 : Relay
relay4 : Relay
relay5 : Relay
relay6 : Relay
relay7 : Relay
relay8 : Relay
attributetypemodifiable ?
logicalName  String  modifiable
advertisedValue  String  read-only
state  A/B  modifiable
stateAtPowerOn  Enumerated  modifiable
maxTimeOnStateA  Time  modifiable
maxTimeOnStateB  Time  modifiable
output  On/Off  modifiable
pulseTimer  Time  modifiable
delayedPulseTimer  Aggregate  modifiable
countdown  Time  read-only

6.3. Module control interface

This interface is identical for all Yoctopuce USB modules. It can be used to control the module global parameters, and to enumerate the functions provided by each module.

productName

Character string containing the commercial name of the module, as set by the factory.

serialNumber

Character string containing the serial number, unique and programmed at the factory. For a Yocto-MaxiRelay module, this serial number always starts with HI8PWER1. You can use the serial number to access a given module by software.

logicalName

Character string containing the logical name of the module, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access a given module. If two modules with the same logical name are in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

productId

USB device identifier of the module, preprogrammed to 32 at the factory.

productRelease

Release number of the module hardware, preprogrammed at the factory.

firmwareRelease

Release version of the embedded firmware, changes each time the embedded software is updated.

persistentSettings

State of persistent module settings: loaded from flash memory, modified by the user or saved to flash memory.

luminosity

Lighting strength of the informative leds (e.g. the Yocto-Led) contained in the module. It is an integer value which varies between 0 (leds turned off) and 100 (maximum led intensity). The default value is 50. To change the strength of the module leds, or to turn them off completely, you only need to change this value.

beacon

Activity of the localization beacon of the module.

upTime

Time elapsed since the last time the module was powered on.

usbCurrent

Current consumed by the module on the USB bus, in milli-amps.

rebootCountdown

Countdown to use for triggering a reboot of the module.

usbBandwidth

Number of USB interfaces used by the device. If this parameter is set to DOUBLE, the device can send twice as much data, but this may saturate the USB hub. Remember to call the saveToFlash() method and then to reboot the module to apply this setting.

6.4. Relay function interface

The Yoctopuce application programming interface allows you to switch the relay state. This change is not persistent: the relay will automatically return to its idle position whenever power is lost or if the module is restarted. The library can also generate automatically short pulses of determined duration. On devices with two output for each relay (double throw), the two outputs are named A and B, with output A corresponding to the idle position (at power off) and the output B corresponding to the active state. If you prefer the alternate default state, simply switch your cables on the board.

logicalName

Character string containing the logical name of the relay, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the relay directly. If two relays with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among A..Z,a..z,0..9,_, and -.

advertisedValue

Short character string summarizing the current state of the relay, that will be automatically advertised up to the parent hub. For a relay, the advertised value is the the relays state (A for the idle position, B for the active position).

state

Active output of the relays: A for the idle position, B for the active position.

stateAtPowerOn

Active output of the relays at device power up: A for the idle position, B for the active position, UNCHANGED to leave the relay as is.

maxTimeOnStateA

Maximum time (ms) allowed for relays to stay in state A before automatically switching back in to B state. Zéro means no maximum time.

maxTimeOnStateB

Maximum time (ms) allowed for relays to stay in state B before automatically switching back in to A state. Zéro means no maximum time.

output

Output state of the relays, when used as a simple switch (single throw).

pulseTimer

Time during which the relays should be kept in state B (active) before returning automatically to state A (idle state). Any explicit state change issued afterwards will cancel the automated switch.

delayedPulseTimer

Delayed pulse parameters.

countdown

Waiting delay before next pulse (delayed pulse case).

6.5. What interface: Native, DLL or Service ?

There are several methods to control you Yoctopuce module by software.

Native control

In this case, the software driving your project is compiled directly with a library which provides control of the modules. Objectively, it is the simplest and most elegant solution for the end user. The end user then only needs to plug the USB cable and run your software for everything to work. Unfortunately, this method is not always available or even possible.


The application uses the native library to control the locally connected module

Native control by DLL

Here, the main part of the code controlling the modules is located in a DLL. The software is compiled with a small library which provides control of the DLL. It is the fastest method to code module support in a given language. Indeed, the "useful" part of the control code is located in the DLL which is the same for all languages: the effort to support a new language is limited to coding the small library which controls the DLL. From the end user stand point, there are few differences: one must simply make sure that the DLL is installed on the end user's computer at the same time as the main software.


The application uses the DLL to natively control the locally connected module

Control by service

Some languages do simply not allow you to easily gain access to the hardware layers of the machine. It is the case for Javascript, for instance. To deal with this case, Yoctopuce provides a solution in the form of a small piece of software called Virtual Hub11. It can access the modules, and your application only needs to use a library which offers all necessary functions to control the modules via this virtual hub. The end users will have to start the virtual hub before running the project control software itself, unless they decide to install the hub as a service/deamon, in which case the virtual hub starts automatically when the machine starts up.


The application connects itself to the virtual hub to gain access to the module

The service control method comes with a non-negligible advantage: the application does not need to run on the machine on which the modules are connected. The application can very well be located on another machine which connects itself to the service to drive the modules. Moreover, the native libraries and DLL mentioned above are also able to connect themselves remotely to one or several virtual hubs.


When a virtual hub is used, the control application does not need to reside on the same machine as the module.

Whatever the selected programming language and the control paradigm used, programming itself stays strictly identical. From one language to another, functions bear exactly the same name, and have the same parameters. The only differences are linked to the constraints of the languages themselves.

Language Native  Native with DLL  Virtual hub 
C++
Objective-C -
Delphi -
Python -
VisualBasic .Net -
C# .Net -
Javascript - -
Node.js - -
PHP - -
Java - -
Java for Android -
Command line -

Support methods for different languages

Limitations of the Yoctopuce libraries

Natives et DLL libraries have a technical limitation. On the same computer, you cannot concurrently run several applications accessing Yoctopuce devices directly. If you want to run several projects on the same computer, make sure your control applications use Yoctopuce devices through a VirtualHub software. The modification is trivial: it is just a matter of parameter change in the yRegisterHub() call.

6.6. Programming, where to start?

At this point of the user's guide, you should know the main theoretical points of your Yocto-MaxiRelay. It is now time to practice. You must download the Yoctopuce library for your favorite programming language from the Yoctopuce web site12. Then skip directly to the chapter corresponding to the chosen programming language.

All the examples described in this guide are available in the programming libraries. For some languages, the libraries also include some complete graphical applications, with their source code.

When you have mastered the basic programming of your module, you can turn to the chapter on advanced programming that describes some techniques that will help you make the most of your Yocto-MaxiRelay.

7. Using the Yocto-MaxiRelay in command line

When you want to perform a punctual operation on your Yocto-MaxiRelay, such as reading a value, assigning a logical name, and so on, you can obviously use the Virtual Hub, but there is a simpler, faster, and more efficient method: the command line API.

The command line API is a set of executables, one by type of functionality offered by the range of Yoctopuce products. These executables are provided pre-compiled for all the Yoctopuce officially supported platforms/OS. Naturally, the executable sources are also provided13.

7.1. Installing

Download the command line API14. You do not need to run any setup, simply copy the executables corresponding to your platform/OS in a directory of your choice. You may add this directory to your PATH variable to be able to access these executables from anywhere. You are all set, you only need to connect your Yocto-MaxiRelay, open a shell, and start working by typing for example:

C:\>YRelay any set_ouput ON

To use the command API on Linux, you need either have root privileges or to define an udev rule for your system. See the Troubleshooting chapter for more details.

7.2. Use: general description

All the command line API executables work on the same principle. They must be called the following way


C:\>Executable [options] [target] command [parameter]

[options] manage the global workings of the commands, they allow you, for instance, to pilot a module remotely through the network, or to force the module to save its configuration after executing the command.

[target] is the name of the module or of the function to which the command applies. Some very generic commands do not need a target. You can also use the aliases "any" and "all", or a list of names separated by comas without space.

command is the command you want to run. Almost all the functions available in the classic programming APIs are available as commands. You need to respect neither the case nor the underlined characters in the command name.

[parameters] logically are the parameters needed by the command.

At any time, the command line API executables can provide a rather detailed help. Use for instance:


C:\>executable /help

to know the list of available commands for a given command line API executable, or even:


C:\>executable command /help

to obtain a detailed description of the parameters of a command.

7.3. Control of the Relay function

To control the Relay function of your Yocto-MaxiRelay, you need the YRelay executable file.

For instance, you can launch:

C:\>YRelay any set_ouput ON

This example uses the "any" target to indicate that we want to work on the first Relay function found among all those available on the connected Yoctopuce modules when running. This prevents you from having to know the exact names of your function and of your module.

But you can use logical names as well, as long as you have configured them beforehand. Let us imagine a Yocto-MaxiRelay module with the HI8PWER1-123456 serial number which you have called "MyModule", and its relay1 function which you have renamed "MyFunction". The five following calls are strictly equivalent (as long as MyFunction is defined only once, to avoid any ambiguity).


C:\>YRelay HI8PWER1-123456.relay1 describe

C:\>YRelay HI8PWER1-123456.MyFunction describe

C:\>YRelay MyModule.relay1 describe

C:\>YRelay MyModule.MyFunction describe

C:\>YRelay MyFunction describe

To work on all the Relay functions at the same time, use the "all" target.


C:\>YRelay all describe

For more details on the possibilities of the YRelay executable, use:


C:\>YRelay /help

7.4. Control of the module part

Each module can be controlled in a similar way with the help of the YModule executable. For example, to obtain the list of all the connected modules, use:


C:\>YModule inventory

You can also use the following command to obtain an even more detailed list of the connected modules:


C:\>YModule all describe

Each xxx property of the module can be obtained thanks to a command of the get_xxxx() type, and the properties which are not read only can be modified with the set_xxx() command. For example:


C:\>YModule HI8PWER1-12346 set_logicalName MonPremierModule

C:\>YModule HI8PWER1-12346 get_logicalName

Changing the settings of the module

When you want to change the settings of a module, simply use the corresponding set_xxx command. However, this change happens only in the module RAM: if the module restarts, the changes are lost. To store them permanently, you must tell the module to save its current configuration in its nonvolatile memory. To do so, use the saveToFlash command. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash method. For example:


C:\>YModule HI8PWER1-12346 set_logicalName MonPremierModule
C:\>YModule HI8PWER1-12346 saveToFlash

Note that you can do the same thing in a single command with the -s option.


C:\>YModule -s  HI8PWER1-12346 set_logicalName MonPremierModule

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

7.5. Limitations

The command line API has the same limitation than the other APIs: there can be only one application at a given time which can access the modules natively. By default, the command line API works in native mode.

You can easily work around this limitation by using a Virtual Hub: run the VirtualHub15 on the concerned machine, and use the executables of the command line API with the -r option. For example, if you use:


C:\>YModule  inventory

you obtain a list of the modules connected by USB, using a native access. If another command which accesses the modules natively is already running, this does not work. But if you run a Virtual Hub, and you give your command in the form:


C:\>YModule -r 127.0.0.1 inventory

it works because the command is not executed natively anymore, but through the Virtual Hub. Note that the Virtual Hub counts as a native application.

8. Using Yocto-MaxiRelay with Javascript

Javascript is probably not the first language that comes to mind to control hardware, but its ease of use is a great advantage: with Javascript, you only need a text editor and a web browser to realize your first tests.

At the time of writing, the Javascript library functions with any recent browser ... except Opera. It is likely that Opera will end up working with the Yoctopuce library one of these days16, but it is not the case right now.

Javascript is one of those languages which do not allow you to directly access the hardware layers of your computer. Therefore you need to run the Yoctopuce TCP/IP to USB gateway, named VirtualHub, on the machine on which your modules are connected.

8.1. Getting ready

Go to the Yoctopuce web site and download the following items:

Decompress the library files in a folder of your choice, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.

8.2. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a JavaScript code snipplet to use the Relay function.


<SCRIPT type="text/javascript" src="yocto_api.js"></SCRIPT>
<SCRIPT type="text/javascript" src="yocto_relay.js"></SCRIPT>

// Get access to your device, through the VirtualHub running locally
yRegisterHub('http://127.0.0.1:4444/');
var relay = yFindRelay("HI8PWER1-123456.relay1");

// Check that the module is online to handle hot-plug
if(relay.isOnline())
{
    // Use relay.set_state(), ...
}

Let us look at these lines in more details.

yocto_api.js and yocto_relay.js

These two Javascript includes provide access to functions allowing you to manage Yoctopuce modules. yocto_api.js must always be included, yocto_relay.js is necessary to manage modules containing a relay, such as Yocto-MaxiRelay.

yRegisterHub

The yRegisterHub function allows you to indicate on which machine the Yoctopuce modules are located, more precisely on which machine the VirtualHub software is running. In our case, the 127.0.0.1:4444 address indicates the local machine, port 4444 (the standard port used by Yoctopuce). You can very well modify this address, and enter the address of another machine on which the VirtualHub software is running.

yFindRelay

The yFindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can also use logical names, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


var relay = yFindRelay("HI8PWER1-123456.relay1");
var relay = yFindRelay("HI8PWER1-123456.MyFunction");
var relay = yFindRelay("MyModule.relay1");
var relay = yFindRelay("MyModule.MyFunction");
var relay = yFindRelay("MyFunction");

yFindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by yFindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by yFindRelay switches the relay position to one of its two outputs. The two possible parameter values are Y_STATE_A for output A, and Y_STATE_B for output B.

A real example

Open your preferred text editor19, copy the code sample below, save it in the same directory as the Yoctopuce library files and then use your preferred web browser to access this page. The code is also provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

The example is coded to be used either from a web server, or directly by opening the file on the local machine. Note that this latest solution does not work with some versions of Internet Explorer, in particular IE 9 on Windows 7, which is not able to open network connections when working on a local file. In order to use Internet Explorer, you should load the example from a web server. No such problem exists with Chrome, Firefox or Safari.

If your Yocto-MaxiRelay is not connected on the host running the browser, replace in the example the address 127.0.0.1 by the IP address of the host on which the Yocto-MaxiRelay is connected and where you run the VirtualHub.

<HTML>
<HEAD>
 <TITLE>Hello World</TITLE>
 <SCRIPT type="text/javascript" src="yocto_api.js"></SCRIPT>
 <SCRIPT type="text/javascript" src="yocto_relay.js"></SCRIPT>
 <SCRIPT language='javascript1.5' type='text/JavaScript'>
 <!--

 // Setup the API to use the VirtualHub on local machine
 if(yRegisterHub('http://127.0.0.1:4444/') != YAPI_SUCCESS) {
     alert("Cannot contact VirtualHub on 127.0.0.1");
 }

 var r = new  Array();
 function refresh()
 {
     var serial = document.getElementById('serial').value;
     if(serial == '') {
         // Detect any connected module suitable for the demo
         r[1] = yFirstRelay();
         if(r[1]) {
             serial = r[1].module().get_serialNumber();
             document.getElementById('serial').value = serial;
         }
     }
   
     for (var i=1;i<=8;i++)
     r[i] = yFindRelay(serial+".relay"+i);
   
     if(r[1].isOnline()) {
         document.getElementById('msg').value = '';
     } else {
         document.getElementById('msg').value = 'Module not connected';        
     }
     setTimeout('refresh()',500);
 }

 function sw(relay,state)
 {
     if (state) relay.set_output(Y_OUTPUT_ON);
           else relay.set_output(Y_OUTPUT_OFF);
 }
 -->
 </SCRIPT>
</HEAD>  
<BODY onload='refresh();'>
 Module to use: <input id='serial'>
 <input id='msg' style='color:red;border:none;' readonly><br>
 Relay1 <a href='javascript:sw(r[1],0);' >A</a> / <a href='javascript:sw(r[1],1);'>B</a><br>
 Relay2 <a href='javascript:sw(r[2],0);' >A</a> / <a href='javascript:sw(r[2],1);'>B</a><br>
 Relay3 <a href='javascript:sw(r[3],0);' >A</a> / <a href='javascript:sw(r[3],1);'>B</a><br>
 Relay4 <a href='javascript:sw(r[4],0);' >A</a> / <a href='javascript:sw(r[4],1);'>B</a><br>
 Relay5 <a href='javascript:sw(r[5],0);' >A</a> / <a href='javascript:sw(r[5],1);'>B</a><br>
 Relay6 <a href='javascript:sw(r[6],0);' >A</a> / <a href='javascript:sw(r[6],1);'>B</a><br>
 Relay7 <a href='javascript:sw(r[7],0);' >A</a> / <a href='javascript:sw(r[7],1);'>B</a><br>
 Relay8 <a href='javascript:sw(r[8],0);' >A</a> / <a href='javascript:sw(r[8],1);'>B</a><br>
 </BODY>
</HTML>
 

8.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

<HTML>
<HEAD>
 <TITLE>Module Control</TITLE>
 <SCRIPT type="text/javascript" src="yocto_api.js"></SCRIPT>
 <SCRIPT language='javascript1.5'  type='text/JavaScript'>
 <!--
 // Use explicit error handling rather than exceptions
 yDisableExceptions();

 // Setup the API to use the VirtualHub on local machine
 if(yRegisterHub('http://127.0.0.1:4444/') != YAPI_SUCCESS) {
     alert("Cannot contact VirtualHub on 127.0.0.1");
 }

 var module;

 function refresh()
 {
     var serial = document.getElementById('serial').value;
     if(serial == '') {
         // Detect any conected module suitable for the demo
         module = yFirstModule().nextModule();
         if(module) {
             serial = module.get_serialNumber();
             document.getElementById('serial').value = serial;
         }
     }

     module = yFindModule(serial);
     if(module.isOnline()) {
         document.getElementById('msg').value = '';
         var html = 'serial: '+module.get_serialNumber()+'<br>';
         html += 'logical name: '+module.get_logicalName()+'<br>';
         html += 'luminosity:'+module.get_luminosity()+'%<br>';
         html += 'beacon:';
         if (module.get_beacon()==Y_BEACON_ON)  
             html+="ON <a href='javascript:beacon(Y_BEACON_OFF)'>switch off</a><br>";
         else  
             html+="OFF <a href='javascript:beacon(Y_BEACON_ON)'>switch on</a><br>";        
         html += 'upTime: '+parseInt(module.get_upTime()/1000)+' sec<br>';
         html += 'USB current: '+module.get_usbCurrent()+' mA<br>';
         html += 'logs:<br><pre>'+module.get_lastLogs()+'</pre><br>';
         document.getElementById('data').innerHTML = html;
     } else {
         document.getElementById('msg').value = 'Module not connected';        
     }
     setTimeout('refresh()',1000);
 }

 function beacon(state)
 {
     module.set_beacon(state);
     refresh();
 }
 -->
 </SCRIPT>
</HEAD>  
<BODY onload='refresh();'>
 Module to use: <input id='serial'>
 <input id='msg' style='color:red;border:none;' readonly><br>
 <span id='data'></span>
</BODY>
</HTML>
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

<HTML>
<HEAD>
 <TITLE>Change module settings</TITLE>
 <SCRIPT type="text/javascript" src="yocto_api.js"></SCRIPT>
 <SCRIPT language='javascript1.5'  type='text/JavaScript'>
 <!--
 // Use explicit error handling rather than exceptions
 yDisableExceptions();

 // Setup the API to use the VirtualHub on local machine
 if(yRegisterHub('http://127.0.0.1:4444/') != YAPI_SUCCESS) {
     alert("Cannot contact VirtualHub on 127.0.0.1");
 }

 var module;

 function refresh()
 {
     var serial = document.getElementById('serial').value;
     if(serial == '') {
         // Detect any conected module suitable for the demo
         module = yFirstModule().nextModule();
         if(module) {
             serial = module.get_serialNumber();
             document.getElementById('serial').value = serial;
         }
     }

     module = yFindModule(serial);
     if(module.isOnline()) {
         document.getElementById('msg').value = '';
         document.getElementById('curName').value = module.get_logicalName();
     } else {
         document.getElementById('msg').value = 'Module not connected';        
     }
     setTimeout('refresh()',1000);
 }

 function save()
 {
     var newname = document.getElementById('newName').value;
     if (!yCheckLogicalName(newname)) {
         alert('invalid logical name');
         return;
     }
     module.set_logicalName(newname);
     module.saveToFlash();
 }  
 -->
 </SCRIPT>
</HEAD>  
<BODY onload='refresh();'>
 Module to use: <input id='serial'>
 <input id='msg' style='color:red;border:none;' readonly><br>
 Current name: <input id='curName' readonly><br>
 New logical name: <input id='newName'>
 <a href='javascript:save();'>Save</a>
</BODY>
</HTML>
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

<HTML>
<HEAD>
 <TITLE>Modules inventory</TITLE>
 <SCRIPT type="text/javascript" src="yocto_api.js"></SCRIPT>
 <SCRIPT language='javascript1.5'  type='text/JavaScript'>
 <!--
 // Use explicit error handling rather than exceptions
 yDisableExceptions();

 // Setup the API to use the VirtualHub on local machine
 if(yRegisterHub('http://127.0.0.1:4444/') != YAPI_SUCCESS) {
     alert("Cannot contact VirtualHub on 127.0.0.1");
 }

 function refresh()
 {
     yUpdateDeviceList();

     var htmlcode = '';
     var module = yFirstModule();
     while(module) {
         htmlcode += module.get_serialNumber()
                     +'('+module.get_productName()+")<br>";
         module = module.nextModule();
     }
     document.getElementById('list').innerHTML=htmlcode;
     setTimeout('refresh()',500);
 }
 -->
 </SCRIPT>
</HEAD>  
<BODY onload='refresh();'>
 <H1>Device list</H1>
 <tt><span id='list'></span></tt>
</BODY>
</HTML>
 

8.4. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

9. Using Yocto-MaxiRelay with PHP

PHP is, like Javascript, an atypical language when interfacing with hardware is at stakes. Nevertheless, using PHP with Yoctopuce modules provides you with the opportunity to very easily create web sites which are able to interact with their physical environment, and this is not available to every web server. This technique has a direct application in home automation: a few Yoctopuce modules, a PHP server, and you can interact with your home from anywhere on the planet, as long as you have an internet connection.

PHP is one of those languages which do not allow you to directly access the hardware layers of your computer. Therefore you need to run a virtual hub on the machine on which your modules are connected.

To start your tests with PHP, you need a PHP 5.3 (or more) server20, preferably locally on you machine. If you wish to use the PHP server of your internet provider, it is possible, but you will probably need to configure your ADSL router for it to accept and forward TCP request on the 4444 port.

9.1. Getting ready

Go to the Yoctopuce web site and download the following items:

Decompress the library files in a folder of your choice accessible to your web server, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.

9.2. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a PHP code snipplet to use the Relay function.


include('yocto_api.php');
include('yocto_relay.php');

// Get access to your device, through the VirtualHub running locally
yRegisterHub('http://127.0.0.1:4444/',$errmsg);
$relay = yFindRelay("HI8PWER1-123456.relay1");

// Check that the module is online to handle hot-plug
if(relay->isOnline())
{
    // Use relay->set_state(), ...
}

Let's look at these lines in more details.

yocto_api.php and yocto_relay.php

These two PHP includes provides access to the functions allowing you to manage Yoctopuce modules. yocto_api.php must always be included, yocto_relay.php is necessary to manage modules containing a relay, such as Yocto-MaxiRelay.

yRegisterHub

The yRegisterHub function allows you to indicate on which machine the Yoctopuce modules are located, more precisely on which machine the VirtualHub software is running. In our case, the 127.0.0.1:4444 address indicates the local machine, port 4444 (the standard port used by Yoctopuce). You can very well modify this address, and enter the address of another machine on which the VirtualHub software is running.

yFindRelay

The yFindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


$relay = yFindRelay("HI8PWER1-123456.relay1");
$relay = yFindRelay("HI8PWER1-123456.MyFunction");
$relay = yFindRelay("MyModule.relay1");
$relay = yFindRelay("MyModule.MyFunction");
$relay = yFindRelay("MyFunction");

yFindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by yFindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by yFindRelay switches the relay position to one of its two outputs. The two possible parameter values are Y_STATE_A for output A, and Y_STATE_B for output B.

A real example

Open your preferred text editor23, copy the code sample below, save it with the Yoctopuce library files in a location which is accessible to you web server, then use your preferred web browser to access this page. The code is also provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

<HTML>
<HEAD>
 <TITLE>Hello World</TITLE>
</HEAD>  
<BODY>
<FORM method='get'>
<?php
  include('yocto_api.php');
  include('yocto_relay.php');

  // Use explicit error handling rather than exceptions
  yDisableExceptions();

  // Setup the API to use the VirtualHub on local machine
  if(yRegisterHub('http://127.0.0.1:4444/',$errmsg) != YAPI_SUCCESS)
      die("Cannot contact VirtualHub on 127.0.0.1");
   
  @$serial = $_GET['serial'];
  $relay = Array();
 
  if ($serial == '')
   { //  use any connected module suitable for the demo
     $relay[1] = yFirstRelay();  
     if(is_null($relay[1])) die("No module connected (check USB cable)");
     $serial = $relay[1]->module()->get_serialnumber();
   }
     
  for ($i=1;$i<=8;$i++) $relay[$i] = yFindRelay("$serial.relay$i");  
   
  if (!$relay[1]->isOnline())  
          die("Module not connected (check serial and USB cable)");
     
  Print("Module to use: <input name='serial' value='$serial'><br>");

  // Drive the selected module
  for ($i=1;$i<=8;$i++)
   if (isset($_GET["state$i"])) {
      $state = $_GET["state$i"];  
      if ($state=='ON') $relay[$i]->set_output(Y_OUTPUT_ON);
                  else $relay[$i]->set_output(Y_OUTPUT_OFF);
   }
 
  // display very primitive UI
  for ($i=1;$i<=8;$i++)
   { $state = $relay[$i]->get_output();
     $ON  ='';  $OFF  ='';
     if  ($relay[$i]->get_output()==Y_OUTPUT_ON) $ON='checked'; else  $OFF='checked';
     Print("Relay $i: <input type='radio' $ON name='state$i' value='ON'>ON");
     Print ("<input type='radio' $OFF name='state$i' value='OFF'>OFF<br>\n");
   }
 ?>
 
 <input type='submit'>
</FORM>
</BODY>
</HTML>
 

9.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

<HTML>
<HEAD>
 <TITLE>Module Control</TITLE>
</HEAD>
<BODY>
<FORM method='get'>
<?php
  include('yocto_api.php');

  // Use explicit error handling rather than exceptions
  yDisableExceptions();

  // Setup the API to use the VirtualHub on local machine
  if(yRegisterHub('http://127.0.0.1:4444/',$errmsg) != YAPI_SUCCESS) {
      die("Cannot contact VirtualHub on 127.0.0.1 : ".$errmsg);
  }

  @$serial = $_GET['serial'];
  if ($serial != '') {
      // Check if a specified module is available online
      $module = yFindModule("$serial");  
      if (!$module->isOnline()) {
          die("Module not connected (check serial and USB cable)");
      }
  } else {
      // or use any connected module suitable for the demo
      $module = yFirstModule();
      if($module) { // skip VirtualHub
          $module = $module->nextModule();
      }
      if(is_null($module)) {
          die("No module connected (check USB cable)");
      } else {
          $serial = $module->get_serialnumber();
      }
  }
  Print("Module to use: <input name='serial' value='$serial'><br>");

  if (isset($_GET['beacon'])) {
      if ($_GET['beacon']=='ON')
          $module->set_beacon(Y_BEACON_ON);
      else  
          $module->set_beacon(Y_BEACON_OFF);
  }          
  printf('serial: %s<br>',$module->get_serialNumber());
  printf('logical name: %s<br>',$module->get_logicalName());
  printf('luminosity: %s<br>',$module->get_luminosity());
  print('beacon: ');
  if($module->get_beacon() == Y_BEACON_ON) {
      printf("<input type='radio' name='beacon' value='ON' checked>ON ");
      printf("<input type='radio' name='beacon' value='OFF'>OFF<br>");
  } else {
      printf("<input type='radio' name='beacon' value='ON'>ON ");
      printf("<input type='radio' name='beacon' value='OFF' checked>OFF<br>");
  }
  printf('upTime: %s sec<br>',intVal($module->get_upTime()/1000));
  printf('USB current: %smA<br>',$module->get_usbCurrent());
  printf('logs:<br><pre>%s</pre>',$module->get_lastLogs());
?>  
<input type='submit' value='refresh'>
</FORM>
</BODY>
</HTML>
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

<HTML>
<HEAD>
 <TITLE>save settings</TITLE>
<BODY>
<FORM method='get'>
<?php
  include('yocto_api.php');
 
  // Use explicit error handling rather than exceptions
  yDisableExceptions();

  // Setup the API to use the VirtualHub on local machine
  if(yRegisterHub('http://127.0.0.1:4444/',$errmsg) != YAPI_SUCCESS) {
      die("Cannot contact VirtualHub on 127.0.0.1");
  }

  @$serial = $_GET['serial'];
  if ($serial != '') {
      // Check if a specified module is available online
      $module = yFindModule("$serial");  
      if (!$module->isOnline()) {
          die("Module not connected (check serial and USB cable)");
      }
  } else {
      // or use any connected module suitable for the demo
      $module = yFirstModule();
      if($module) { // skip VirtualHub
          $module = $module->nextModule();
      }
      if(is_null($module)) {
          die("No module connected (check USB cable)");
      } else {
          $serial = $module->get_serialnumber();
      }
  }
  Print("Module to use: <input name='serial' value='$serial'><br>");

  if (isset($_GET['newname'])){
      $newname = $_GET['newname'];
      if (!yCheckLogicalName($newname))
          die('Invalid name');
      $module->set_logicalName($newname);
      $module->saveToFlash();
  }
  printf("Current name: %s<br>", $module->get_logicalName());
  print("New name: <input name='newname' value='' maxlength=19><br>");
?>
<input type='submit'>
</FORM>
</BODY>
</HTML>
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

<HTML>
<HEAD>
 <TITLE>inventory</TITLE>
</HEAD>
<BODY>
<H1>Device list</H1>
<TT>
<?php
    include('yocto_api.php');
    yRegisterHub("http://127.0.0.1:4444/");
    $module   = yFirstModule();
    while (!is_null($module)) {
        printf("%s (%s)<br>", $module->get_serialNumber(),
               $module->get_productName());
        $module=$module->nextModule();
    }
?>
</TT>
</BODY>
</HTML>
 

9.4. HTTP callback API and NAT filters

The PHP library is able to work in a specific mode called HTTP callback Yocto-API. With this mode, you can control Yoctopuce devices installed behind a NAT filter, such as a DSL router for example, and this without needing to open a port. The typical application is to control Yoctopuce devices, located on a private network, from a public web site.

The NAT filter: advantages and disadvantages

A DSL router which translates network addresses (NAT) works somewhat like a private phone switchboard (a PBX): internal extensions can call each other and call the outside; but seen from the outside, there is only one official phone number, that of the switchboard itself. You cannot reach the internal extensions from the outside.


Typical DSL configuration: LAN machines are isolated from the outside by the DSL router

Transposed to the network, we have the following: appliances connected to your home automation network can communicate with one another using a local IP address (of the 192.168.xxx.yyy type), and contact Internet servers through their public address. However, seen from the outside, you have only one official IP address, assigned to the DSL router only, and you cannot reach your network appliances directly from the outside. It is rather restrictive, but it is a relatively efficient protection against intrusions.


Responses from request from LAN machines are routed.


But requests from the outside are blocked.

Seeing Internet without being seen provides an enormous security advantage. However, this signifies that you cannot, a priori, set up your own web server at home to control a home automation installation from the outside. A solution to this problem, advised by numerous home automation system dealers, consists in providing outside visibility to your home automation server itself, by adding a routing rule in the NAT configuration of the DSL router. The issue of this solution is that it exposes the home automation server to external attacks.

The HTTP callback API solves this issue without having to modify the DSL router configuration. The module control script is located on an external site, and it is the VirtualHub which is in charge of calling it a regular intervals.


The HTTP callback API uses the VirtualHub which initiates the requests.

Configuration

The callback API thus uses the VirtualHub as a gateway. All the communications are initiated by the VirtualHub. They are thus outgoing communications and therefore perfectly authorized by the DSL router.

You must configure the VirtualHub so that it calls the PHP script on a regular basis. To do so:

  1. Launch a VirtualHub
  2. Access its interface, usually 127.0.0.1:4444
  3. Click on the configure button of the line corresponding to the VirtualHub itself
  4. Click on the edit button of the Outgoing callbacks section


Click on the "configure" button on the first line


Click on the "edit" button of the "Outgoing callbacks" section


And select "Yocto-API callback".

You then only need to define the URL of the PHP script and, if need be, the user name and password to access this URL. Supported authentication methods are basic and digest. The second method is safer than the first one because it does not allow transfer of the password on the network.

Usage

From the programmer standpoint, the only difference is at the level of the yRegisterHub function call. Instead of using an IP address, you must use the callback string (or http://callback which is equivalent).


include("yocto_api.php");
yRegisterHub("callback");

The remainder of the code stays strictly identical. On the VirtualHub interface, at the bottom of the configuration window for the HTTP callback API , there is a button allowing you to test the call to the PHP script.

Be aware that the PHP script controlling the modules remotely through the HTTP callback API can be called only by the VirtualHub. Indeed, it requires the information posted by the VirtualHub to function. To code a web site which controls Yoctopuce modules interactively, you must create a user interface which stores in a file or in a database the actions to be performed on the Yoctopuce modules. These actions are then read and run by the control script.

Common issues

For the HTTP callback API to work, the PHP option allow_url_fopen must be set. Some web site hosts do not set it by default. The problem then manifests itself with the following error:

error: URL file-access is disabled in the server configuration

To set this option, you must create, in the repertory where the control PHP script is located, an .htaccess file containing the following line:
php_flag "allow_url_fopen" "On"
Depending on the security policies of the host, it is sometimes impossible to authorize this option at the root of the web site, or even to install PHP scripts receiving data from a POST HTTP. In this case, place the PHP script in a subdirectory.

Limitations

This method that allows you to go through NAT filters cheaply has nevertheless a price. Communications being initiated by the VirtualHub at a more or less regular interval, reaction time to an event is clearly longer than if the Yoctopuce modules were driven directly. You can configure the reaction time in the specific window of the VirtualHub, but it is at least of a few seconds in the best case.

The HTTP callback Yocto-API mode is currently available in PHP and Node.JS only.

9.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

10. Using Yocto-MaxiRelay with C++

C++ is not the simplest language to master. However, if you take care to limit yourself to its essential functionalities, this language can very well be used for short programs quickly coded, and it has the advantage of being easily ported from one operating system to another. Under Windows, all the examples and the project models are tested with Microsoft Visual Studio 2010 Express, freely available on the Microsoft web site24. Under Mac OS X, all the examples and project models are tested with XCode 4, available on the App Store. Moreover, under Max OS X and under Linux, you can compile the examples using a command line with GCC using the provided GNUmakefile. In the same manner under Windows, a Makefile allows you to compile examples using a command line, fully knowing the compilation and linking arguments.

Yoctopuce C++ libraries25 are integrally provided as source files. A section of the low-level library is written in pure C, but you should not need to interact directly with it: everything was done to ensure the simplest possible interaction from C++. The library is naturally also available as binary files, so that you can link it directly if you prefer.

You will soon notice that the C++ API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface. You will find in the last section of this chapter all the information needed to create a wholly new project linked with the Yoctopuce libraries.

10.1. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a C++ code snipplet to use the Relay function.


#include "yocto_api.h"
#include "yocto_relay.h"

[...]
String  errmsg;
YRelay *relay;

// Get access to your device, connected locally on USB for instance
yRegisterHub("usb", errmsg);
relay = yFindRelay("HI8PWER1-123456.relay1");

// Hot-plug is easy: just check that the device is online
if(relay->isOnline())
{
    // Use relay->set_state(), ...
}

Let's look at these lines in more details.

yocto_api.h et yocto_relay.h

These two include files provide access to the functions allowing you to manage Yoctopuce modules. yocto_api.h must always be used, yocto_relay.h is necessary to manage modules containing a relay, such as Yocto-MaxiRelay.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindRelay

The yFindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


YRelay *relay = yFindRelay("HI8PWER1-123456.relay1");
YRelay *relay = yFindRelay("HI8PWER1-123456.MyFunction");
YRelay *relay = yFindRelay("MyModule.relay1");
YRelay *relay = yFindRelay("MyModule.MyFunction");
YRelay *relay = yFindRelay("MyFunction");

yFindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by yFindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by yFindRelay switches the relay position to one of its two outputs. The two possible parameter values are Y_STATE_A for output A, and Y_STATE_B for output B.

A real example

Launch your C++ environment and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library. If you prefer to work with your favorite text editor, open the file main.cpp, and type make to build the example when you are done.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

#include "yocto_api.h"
#include "yocto_relay.h"
#include <iostream>
#include <ctype.h>
#include <stdlib.h>

using namespace std;

static void usage(const char* execname)
{  
    cout  << "usage:" << endl;
    cout  << execname << " serial_number> <channel>  [ ON | OFF ]" << endl;
    cout  << execname << " <logical_name> <channel>[ ON | OFF ]" << endl;
    cout  << execname << " any <channel> [ ON | OFF ]  (use any discovered device)" << endl;
    cout  << "Example"   << endl;
    cout  << execname << " any 2 ON" << endl;    
    exit(1);
}

int main(int argc, const char * argv[])
{
    string  errmsg;
    string  target;
    string  channel;
    YRelay  *relay;
    string  state;

    if (argc < 3) usage(argv[0]);
   
    target  = (string) argv[1];
    channel = (string) argv[2];
    state   = (string) argv[3];

    // Setup the API to use local USB devices
    if (yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }
   
    if (target == "any") {
        relay =  yFirstRelay();        
        if (relay==NULL) {
            cout << "No module connected (check USB cable)" << endl;
            return 1;
        }
         target = relay->get_module()->get_serialNumber();
    }
     
    cout << "Using " << target << endl;      
    relay =  yFindRelay((string)target + ".relay" + channel);
   

    if (relay->isOnline()) {
       
        relay->set_state(state == "ON" ? Y_STATE_B : Y_STATE_A);
    } else {
        cout << "Module not connected (check identification and USB cable)" << endl;
    }
       
    return 0;
}
 

10.2. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

#include <iostream>
#include <stdlib.h>

#include "yocto_api.h"

using namespace std;

static void usage(const char *exe)
{
    cout << "usage: " << exe << " <serial or logical name> [ON/OFF]" << endl;
    exit(1);
}


int main(int argc, const char * argv[])
{
    string      errmsg;

    // Setup the API to use local USB devices
    if(yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    if(argc < 2)
        usage(argv[0]);

    YModule *module = yFindModule(argv[1]);  // use serial or logical name
 
    if (module->isOnline()) {
        if (argc > 2) {
            if (string(argv[2]) == "ON")
                module->set_beacon(Y_BEACON_ON);
            else  
                module->set_beacon(Y_BEACON_OFF);
        }          
        cout << "serial:       " << module->get_serialNumber() << endl;
        cout << "logical name: " << module->get_logicalName() << endl;
        cout << "luminosity:   " << module->get_luminosity() << endl;
        cout << "beacon:       ";
        if (module->get_beacon()==Y_BEACON_ON)  
           cout << "ON" << endl;
        else  
           cout << "OFF" << endl;
        cout << "upTime:       " << module->get_upTime()/1000 << " sec" << endl;
        cout << "USB current:  " << module->get_usbCurrent() << " mA" << endl;
        cout << "Logs:"<< endl << module->get_lastLogs() << endl;
    } else {
        cout << argv[1] << " not connected (check identification and USB cable)"
             << endl;
    }
    return 0;
}
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

#include <iostream>
#include <stdlib.h>

#include "yocto_api.h"

using namespace std;

static void usage(const char *exe)
{
    cerr << "usage: " << exe << " <serial> <newLogicalName>" << endl;
    exit(1);
}

int main(int argc, const char * argv[])
{
    string      errmsg;

    // Setup the API to use local USB devices
    if(yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    if(argc < 2)
        usage(argv[0]);

    YModule *module = yFindModule(argv[1]);  // use serial or logical name
 
    if (module->isOnline()) {
        if (argc >= 3){
            string newname =  argv[2];
            if (!yCheckLogicalName(newname)){
                cerr << "Invalid name (" << newname << ")" << endl;
                usage(argv[0]);
            }
            module->set_logicalName(newname);
            module->saveToFlash();
        }
        cout << "Current name: " << module->get_logicalName() << endl;
    } else {
        cout << argv[1] << " not connected (check identification and USB cable)"
             << endl;
    }
    return 0;
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

#include <iostream>

#include "yocto_api.h"

using namespace std;

int main(int argc, const char * argv[])
{
    string      errmsg;

    // Setup the API to use local USB devices
    if(yRegisterHub("usb", errmsg) != YAPI_SUCCESS) {
        cerr << "RegisterHub error: " << errmsg << endl;
        return 1;
    }

    cout << "Device list: " << endl;

    YModule *module = yFirstModule();
    while (module != NULL) {
        cout << module->get_serialNumber() << " ";
        cout << module->get_productName()  << endl;
        module = module->nextModule();
    }
    return 0;
}
 

10.3. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

10.4. Integration variants for the C++ Yoctopuce library

Depending on your needs and on your preferences, you can integrate the library into your projects in several distinct manners. This section explains how to implement the different options.

Integration in source format

Integrating all the sources of the library into your projects has several advantages:

To integrate the source code, the easiest way is to simply include the Sources directory of your Yoctopuce library into your IncludePath, and to add all the files of this directory (including the sub-directory yapi) to your project.

For your project to build correctly, you need to link with your project the prerequisite system libraries, that is:

Integration as a static library

Integration of the Yoctopuce library as a static library is a simpler manner to build a small executable which uses Yoctopuce modules. You can quickly compile the program with a single command. You do not need to install a dynamic library specific to Yoctopuce, everything is in the executable.

To integrate the static Yoctopuce library to your project, you must include the Sources directory of the Yoctopuce library into your IncludePath, and add the sub-directory Binaries/... corresponding to your operating system into your libPath.

Then, for you project to build correctly, you need to link with your project the Yoctopuce library and the prerequisite system libraries:

Note, under Linux, if you wish to compile in command line with GCC, it is generally advisable to link system libraries as dynamic libraries, rather than as static ones. To mix static and dynamic libraries on the same command line, you must pass the following arguments:

gcc (...) -Wl,-Bstatic -lyocto-static -Wl,-Bdynamic -lm -lpthread -lusb-1.0 -lstdc++

Integration as a dynamic library

Integration of the Yoctopuce library as a dynamic library allows you to produce an executable smaller than with the two previous methods, and to possibly update this library, if a patch reveals itself necessary, without needing to recompile the source code of the application. On the other hand, it is an integration mode which systematically requires you to copy the dynamic library on the target machine where the application will run (yocto.dll for Windows, libyocto.so.1.0.1 for Mac OS X and Linux).

To integrate the dynamic Yoctopuce library to your project, you must include the Sources directory of the Yoctopuce library into your IncludePath, and add the sub-directory Binaries/... corresponding to your operating system into your LibPath.

Then, for you project to build correctly, you need to link with your project the dynamic Yoctopuce library and the prerequisite system libraries:

With GCC, the command line to compile is simply:

gcc (...) -lyocto -lm -lpthread -lusb-1.0 -lstdc++

11. Using Yocto-MaxiRelay with Objective-C

Objective-C is language of choice for programming on Mac OS X, due to its integration with the Cocoa framework. In order to use the Objective-C library, you need XCode version 4.2 (earlier versions will not work), available freely when you run Lion. If you are still under Snow Leopard, you need to be registered as Apple developer to be able to download XCode 4.2. The Yoctopuce library is ARC compatible. You can therefore implement your projects either using the traditional retain / release method, or using the Automatic Reference Counting.

Yoctopuce Objective-C libraries26 are integrally provided as source files. A section of the low-level library is written in pure C, but you should not need to interact directly with it: everything was done to ensure the simplest possible interaction from Objective-C.

You will soon notice that the Objective-C API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface. You can find on Yoctopuce blog a detailed example27 with video shots showing how to integrate the library into your projects.

11.1. Control of the Relay function

Launch Xcode 4.2 and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

#import <Foundation/Foundation.h>
#import "yocto_api.h"
#import "yocto_relay.h"


static void usage(const char* execname)
{  
    NSLog(@"usage:");
    NSLog(@" %s serial_number> <channel>  [ ON | OFF ]",execname);
    NSLog(@" %s <logical_name> <channel>[ ON | OFF ]",execname);
    NSLog(@" %s any <channel> [ ON | OFF ]  (use any discovered device)",execname);
    NSLog(@"Example");
    NSLog(@" %s any 2 ON",execname);    
    exit(1);
}

int main(int argc, const char * argv[])
{
    NSError *error;

    if (argc < 3) usage(argv[0]);
   
    @autoreleasepool {

        YRelay   *relay;
        NSString *target = [NSString stringWithUTF8String:argv[1]];
        NSString *channel = [NSString stringWithUTF8String:argv[2]];
        NSString *state = [NSString stringWithUTF8String:argv[3]];

                // Setup the API to use local USB devices
        if([YAPI RegisterHub:@"usb": &error] != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@", [error localizedDescription]);
            return 1;
        }
           
                if ([target isEqualToString:@"any"]) {
            relay = [YRelay FirstRelay];
            if (relay==NULL) {
                NSLog(@"No module connected (check USB cable)");
                return 1;
            }
                target = [[relay module] serialNumber];
            }
             
            NSLog(@"Using %@",target);      
        relay =  [YRelay FindRelay:[NSString stringWithFormat:@"%@.relay%@",target,channel]];

            if ([relay isOnline]) {
            if ([state isEqualToString:@"ON"])
                [relay set_state:Y_STATE_B];
            else
                [relay set_state:Y_STATE_A];
            } else {
            NSLog(@"Module not connected (check identification and USB cable)\n");
            }
        }        
    return 0;
}
 

There are only a few really important lines in this example. We will look at them in details.

yocto_api.h et yocto_relay.h

These two import files provide access to the functions allowing you to manage Yoctopuce modules. yocto_api.h must always be used, yocto_relay.h is necessary to manage modules containing a relay, such as Yocto-MaxiRelay.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter @"usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindRelay

The yFindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


YRelay *relay = yFindRelay(@"HI8PWER1-123456.relay1");
YRelay *relay = yFindRelay(@"HI8PWER1-123456.MyFunction");
YRelay *relay = yFindRelay(@"MyModule.relay1");
YRelay *relay = yFindRelay(@"MyModule.MyFunction");
YRelay *relay = yFindRelay(@"MyFunction");

yFindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by yFindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by yFindRelay switches the relay position to one of its two outputs. The two possible parameter values are Y_STATE_A for output A, and Y_STATE_B for output B.

11.2. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

#import <Foundation/Foundation.h>
#import "yocto_api.h"

static void usage(const char *exe)
{
    NSLog(@"usage: %s <serial or logical name> [ON/OFF]\n",exe);
    exit(1);
}


int main (int argc, const char * argv[])
{
    NSError *error;
   
    @autoreleasepool {
        // Setup the API to use local USB devices
        if([YAPI RegisterHub:@"usb": &error] != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@", [error localizedDescription]);
            return 1;
        }
        if(argc < 2)
            usage(argv[0]);
        NSString *serial_or_name =[NSString stringWithUTF8String:argv[1]];
        YModule *module = [YModule FindModule:serial_or_name];  // use serial or logical name
        if ([module isOnline]) {
            if (argc > 2) {
                if (strcmp(argv[2], "ON")==0)
                    [module setBeacon:Y_BEACON_ON];
                else  
                    [module setBeacon:Y_BEACON_OFF];
            }        
            NSLog(@"serial:       %@\n", [module serialNumber]);
            NSLog(@"logical name: %@\n", [module logicalName]);
            NSLog(@"luminosity:   %d\n", [module luminosity]);
            NSLog(@"beacon:       ");
            if ([module beacon] == Y_BEACON_ON)
               NSLog(@"ON\n");
            else  
               NSLog(@"OFF\n");
            NSLog(@"upTime:       %d sec\n", [module upTime]/1000);
            NSLog(@"USB current:  %d mA\n",  [module usbCurrent]);
            NSLog(@"logs:  %@\n",  [module get_lastLogs]);
        } else {
            NSLog(@"%@ not connected (check identification and USB cable)\n",serial_or_name);
        }
    }
    return 0;
}
 

Each property xxx of the module can be read thanks to a method of type get_xxxx, and properties which are not read-only can be modified with the help of the set_xxx: method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx: function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash method. The short example below allows you to modify the logical name of a module.

#import <Foundation/Foundation.h>
#import "yocto_api.h"

static void usage(const char *exe)
{
    NSLog(@"usage: %s <serial> <newLogicalName>\n",exe);
    exit(1);
}


int main (int argc, const char * argv[])
{
    NSError *error;

    @autoreleasepool {
        // Setup the API to use local USB devices
        if(yRegisterHub(@"usb", &error) != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@", [error localizedDescription]);
            return 1;
        }

        if(argc < 2)
            usage(argv[0]);

        NSString *serial_or_name =[NSString stringWithUTF8String:argv[1]];
        YModule *module = yFindModule(serial_or_name);  // use serial or logical name
     
        if (module.isOnline) {
            if (argc >= 3){
                NSString *newname =  [NSString stringWithUTF8String:argv[2]];
                if (!yCheckLogicalName(newname)){
                    NSLog(@"Invalid name (%@)\n", newname);
                    usage(argv[0]);
                }
                module.logicalName = newname;
                [module saveToFlash];
            }
            NSLog(@"Current name: %@\n", module.logicalName);
        } else {
            NSLog(@"%@ not connected (check identification and USB cable)\n",serial_or_name);
        }
    }
    return 0;
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not NULL. Below a short example listing the connected modules.

#import <Foundation/Foundation.h>
#import "yocto_api.h"

int main (int argc, const char * argv[])
{
    NSError *error;
   
    @autoreleasepool {
        // Setup the API to use local USB devices
        if(yRegisterHub(@"usb", &error) != YAPI_SUCCESS) {
            NSLog(@"RegisterHub error: %@\n", [error localizedDescription]);
            return 1;
        }

        NSLog(@"Device list:\n");

        YModule *module = yFirstModule();
        while (module != nil) {
            NSLog(@"%@ %@",module.serialNumber, module.productName);
            module = [module nextModule];
        }
    }
    return 0;
}
 

11.3. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

12. Using Yocto-MaxiRelay with Visual Basic .NET

VisualBasic has long been the most favored entrance path to the Microsoft world. Therefore, we had to provide our library for this language, even if the new trend is shifting to C#. All the examples and the project models are tested with Microsoft VisualBasic 2010 Express, freely available on the Microsoft web site28.

12.1. Installation

Download the Visual Basic Yoctopuce library from the Yoctopuce web site29. There is no setup program, simply copy the content of the zip file into the directory of your choice. You mostly need the content of the Sources directory. The other directories contain the documentation and a few sample programs. All sample projects are Visual Basic 2010, projects, if you are using a previous version, you may have to recreate the projects structure from scratch.

12.2. Using the Yoctopuce API in a Visual Basic project

The Visual Basic.NET Yoctopuce library is composed of a DLL and of source files in Visual Basic. The DLL is not a .NET DLL, but a classic DLL, written in C, which manages the low level communications with the modules30. The source files in Visual Basic manage the high level part of the API. Therefore, your need both this DLL and the .vb files of the sources directory to create a project managing Yoctopuce modules.

Configuring a Visual Basic project

The following indications are provided for Visual Studio Express 2010, but the process is similar for other versions. Start by creating your project. Then, on the Solution Explorer panel, right click on your project, and select "Add" and then "Add an existing item".

A file selection window opens. Select the yocto_api.vb file and the files corresponding to the functions of the Yoctopuce modules that your project is going to manage. If in doubt, select all the files.

You then have the choice between simply adding these files to your project, or to add them as links (the Add button is in fact a scroll-down menu). In the first case, Visual Studio copies the selected files into your project. In the second case, Visual Studio simply keeps a link on the original files. We recommend you to use links, which makes updates of the library much easier.

Then add in the same manner the yapi.dll DLL, located in the Sources/dll directory31. Then, from the Solution Explorer window, right click on the DLL, select Properties and in the Properties panel, set the Copy to output folder to always. You are now ready to use your Yoctopuce modules from Visual Studio.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

12.3. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a Visual Basic code snipplet to use the Relay function.


[...]
Dim errmsg As String errmsg
Dim relay As YRelay
 
REM Get access to your device, connected locally on USB for instance
yRegisterHub("usb", errmsg)
relay = yFindRelay("HI8PWER1-123456.relay1")

REM Hot-plug is easy: just check that the device is online
If (relay.isOnline()) Then
   REM Use relay.set_state(), ...
End If

Let's look at these lines in more details.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindRelay

The yFindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


relay = yFindRelay("HI8PWER1-123456.relay1")
relay = yFindRelay("HI8PWER1-123456.MyFunction")
relay = yFindRelay("MyModule.relay1")
relay = yFindRelay("MyModule.MyFunction")
relay = yFindRelay("MyFunction")

yFindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by yFindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by yFindRelay switches the relay position to one of its two outputs. The two possible parameter values are Y_STATE_A for output A, and Y_STATE_B for output B.

A real example

Launch Microsoft VisualBasic and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

Module Module1

  Private Sub Usage()
    Dim execname As String = System.AppDomain.CurrentDomain.FriendlyName
    Console.WriteLine("Usage:")
    Console.WriteLine(execname + " <serial_number> <channel> [ ON | OFF ]")
    Console.WriteLine(execname + " <logical_name>  <channel> [ ON | OFF ]")
    Console.WriteLine(execname + " any <channel> [ ON | OFF ]")
    Console.WriteLine("Example:")
    Console.WriteLine(execname + " any 1 [ ON | OFF ]")
    System.Threading.Thread.Sleep(2500)
    End
  End Sub

  Sub Main()
    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim errmsg As String = ""
    Dim target, channel As String
    Dim relay As YRelay
    Dim state As String

    If argv.Length < 3 Then Usage()

    target = argv(1)
    channel = argv(2)
    state = argv(3).ToUpper

    REM Setup the API to use local USB devices
    If (yRegisterHub("usb", errmsg) <> YAPI_SUCCESS) Then
      Console.WriteLine("RegisterHub error: " + errmsg)
      End
    End If

    If target = "any" Then
      relay = yFirstRelay()
      If relay Is Nothing Then
        Console.WriteLine("No module connected (check USB cable) ")
        End
      End If
      target = relay.get_module().get_serialNumber()
    End If

    Console.WriteLine("using " + target)
    relay = yFindRelay(target + ".relay" + channel)


    If (relay.isOnline()) Then
      If state = "ON" Then
        relay.set_output(Y_OUTPUT_ON)
      Else
        relay.set_output(Y_OUTPUT_OFF)
      End If
    Else
      Console.WriteLine("Module not connected (check identification and USB cable)")
    End If
  End Sub

End Module
 

12.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.


Imports System.IO
Imports System.Environment

Module Module1

  Sub usage()
    Console.WriteLine("usage: demo <serial or logical name> [ON/OFF]")  
    End
  End Sub

  Sub Main()
    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim errmsg As String = ""
    Dim m As ymodule

    If (yRegisterHub("usb", errmsg) <> YAPI_SUCCESS) Then
      Console.WriteLine("RegisterHub error:" + errmsg)
      End
    End If

    If argv.Length < 2 Then usage()

    m = yFindModule(argv(1)) REM use serial or logical name

    If (m.isOnline()) Then
      If argv.Length > 2 Then
        If argv(2) = "ON" Then m.set_beacon(Y_BEACON_ON)
        If argv(2) = "OFF" Then m.set_beacon(Y_BEACON_OFF)
      End If
      Console.WriteLine("serial:       " + m.get_serialNumber())
      Console.WriteLine("logical name: " + m.get_logicalName())
      Console.WriteLine("luminosity:   " + Str(m.get_luminosity()))
      Console.Write("beacon:       ")
      If (m.get_beacon() = Y_BEACON_ON) Then
        Console.WriteLine("ON")
      Else
        Console.WriteLine("OFF")
      End If
      Console.WriteLine("upTime:       " + Str(m.get_upTime() / 1000) + " sec")
      Console.WriteLine("USB current:  " + Str(m.get_usbCurrent()) + " mA")
      Console.WriteLine("Logs:")
      Console.WriteLine(m.get_lastLogs())
    Else
      Console.WriteLine(argv(1) + " not connected (check identification and USB cable)")
    End If



  End Sub

End Module
 

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

Module Module1


  Sub usage()

    Console.WriteLine("usage: demo <serial or logical name> <new logical name>")
    End
  End Sub

  Sub Main()
    Dim argv() As String = System.Environment.GetCommandLineArgs()
    Dim errmsg As String = ""
    Dim newname As String
    Dim m As YModule

    If (argv.Length <> 3) Then usage()

    REM Setup the API to use local USB devices
    If yRegisterHub("usb", errmsg) <> YAPI_SUCCESS Then
      Console.WriteLine("RegisterHub error: " + errmsg)
      End
    End If

    m = yFindModule(argv(1)) REM use serial or logical name
    If m.isOnline() Then

      newname = argv(2)
      If (Not yCheckLogicalName(newname)) Then
        Console.WriteLine("Invalid name (" + newname + ")")
        End
      End If
      m.set_logicalName(newname)
      m.saveToFlash() REM do not forget this

      Console.Write("Module: serial= " + m.get_serialNumber)
      Console.Write(" / name= " + m.get_logicalName())
    Else
      Console.Write("not connected (check identification and USB cable")
    End If

  End Sub

End Module
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not Nothing. Below a short example listing the connected modules.

Module Module1

  Sub Main()
    Dim M As ymodule
    Dim errmsg As String = ""

    REM Setup the API to use local USB devices
    If yRegisterHub("usb", errmsg) <> YAPI_SUCCESS Then
      Console.WriteLine("RegisterHub error: " + errmsg)
      End
    End If

    Console.WriteLine("Device list")
    M = yFirstModule()
    While M IsNot Nothing
      Console.WriteLine(M.get_serialNumber() + " (" + M.get_productName() + ")")
      M = M.nextModule()
    End While

  End Sub

    End Module
 

12.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

13. Using Yocto-MaxiRelay with C#

C# (pronounced C-Sharp) is an object-oriented programming language promoted by Microsoft, it is somewhat similar to Java. Like Visual-Basic and Delphi, it allows you to create Windows applications quite easily. All the examples and the project models are tested with Microsoft C# 2010 Express, freely available on the Microsoft web site32.

13.1. Installation

Download the Visual C# Yoctopuce library from the Yoctopuce web site33. There is no setup program, simply copy the content of the zip file into the directory of your choice. You mostly need the content of the Sources directory. The other directories contain the documentation and a few sample programs. All sample projects are Visual C# 2010, projects, if you are using a previous version, you may have to recreate the projects structure from scratch.

13.2. Using the Yoctopuce API in a Visual C# project

The Visual C#.NET Yoctopuce library is composed of a DLL and of source files in Visual C#. The DLL is not a .NET DLL, but a classic DLL, written in C, which manages the low level communications with the modules34. The source files in Visual C# manage the high level part of the API. Therefore, your need both this DLL and the .cs files of the sources directory to create a project managing Yoctopuce modules.

Configuring a Visual C# project

The following indications are provided for Visual Studio Express 2010, but the process is similar for other versions. Start by creating your project. Then, on the Solution Explorer panel, right click on your project, and select "Add" and then "Add an existing item".

A file selection window opens. Select the yocto_api.cs file and the files corresponding to the functions of the Yoctopuce modules that your project is going to manage. If in doubt, select all the files.

You then have the choice between simply adding these files to your project, or to add them as links (the Add button is in fact a scroll-down menu). In the first case, Visual Studio copies the selected files into your project. In the second case, Visual Studio simply keeps a link on the original files. We recommend you to use links, which makes updates of the library much easier.

Then add in the same manner the yapi.dll DLL, located in the Sources/dll directory35. Then, from the Solution Explorer window, right click on the DLL, select Properties and in the Properties panel, set the Copy to output folder to always. You are now ready to use your Yoctopuce modules from Visual Studio.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

13.3. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a C# code snipplet to use the Relay function.


[...]
string errmsg ="";
YRelay relay;
 
// Get access to your device, connected locally on USB for instance
YAPI.RegisterHub("usb", errmsg);
relay = YRelay.FindRelay("HI8PWER1-123456.relay1");

// Hot-plug is easy: just check that the device is online
if (relay.isOnline())
 {  // Use relay.set_state(); ...
 }

Let's look at these lines in more details.

YAPI.RegisterHub

The YAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI.SUCCESS and errmsg contains the error message.

YRelay.FindRelay

The YRelay.FindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


relay = YRelay.FindRelay("HI8PWER1-123456.relay1");
relay = YRelay.FindRelay("HI8PWER1-123456.MyFunction");
relay = YRelay.FindRelay("MyModule.relay1");
relay = YRelay.FindRelay("MyModule.MyFunction");
relay = YRelay.FindRelay("MyFunction");

YRelay.FindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by YRelay.FindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by YRelay.FindRelay switches the relay position to one of its two outputs. The two possible parameter values are YRelay.STATE_A for output A, and YRelay.STATE_B for output B.

A real example

Launch Microsoft Visual C# and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
  class Program
  {
    static void usage()
    { string  execname  = System.AppDomain.CurrentDomain.FriendlyName;
      Console.WriteLine("Usage:");
      Console.WriteLine(execname + " <serial_number> <channel> [ ON | OFF ]");
      Console.WriteLine(execname + " <logical_name> <channel>  [ ON | OFF ]");
      Console.WriteLine(execname + " any <channel> [ ON | OFF ]");
      Console.WriteLine("Example:");
      Console.WriteLine(execname + " any 2 ON");
      System.Threading.Thread.Sleep(2500);
     
      Environment.Exit(0);
    }

    static void Main(string[] args)
    {
      string errmsg = "";
      string target;
      YRelay relay;
      string state;
      string  channel;

      if (args.Length < 3) usage();
      target  = args[0].ToUpper();
      channel = args[1];
      state   = args[2].ToUpper();

      if (YAPI.RegisterHub("usb", ref errmsg) != YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

      if (target == "ANY")
      {
        relay = YRelay.FirstRelay();
        if (relay == null)
        {
          Console.WriteLine("No module connected (check USB cable) ");
          Environment.Exit(0);
        }
        target = relay.get_module().get_serialNumber();
      }

      Console.WriteLine("using " + target);
      relay = YRelay.FindRelay(target + ".relay"+channel);

      if (relay.isOnline())
      {
        if (state == "ON")
          relay.set_output(YRelay.OUTPUT_ON);
        else
          relay.set_output(YRelay.OUTPUT_OFF);
      }
      else Console.WriteLine("Module not connected (check identification and USB cable)");
    }
  }
}
 

13.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;


namespace ConsoleApplication1
{
  class Program
  {
    static void usage()
    { string execname = System.AppDomain.CurrentDomain.FriendlyName;
      Console.WriteLine("Usage:");
      Console.WriteLine(execname+" <serial or logical name> [ON/OFF]");
      System.Threading.Thread.Sleep(2500);
      Environment.Exit(0);
    }

    static void Main(string[] args)
    {
      YModule m;
      string errmsg = "";

      if (YAPI.RegisterHub("usb", ref errmsg) !=  YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

     
      if (args.Length < 1)  usage();

      m = YModule.FindModule(args[0]); // use serial or logical name

      if (m.isOnline())
      {
        if (args.Length >= 2)
        {
          if (args[1].ToUpper() == "ON") { m.set_beacon(YModule.BEACON_ON); }
          if (args[1].ToUpper() == "OFF") { m.set_beacon(YModule.BEACON_OFF); }
        }
     
        Console.WriteLine("serial:       " + m.get_serialNumber());
        Console.WriteLine("logical name: " + m.get_logicalName());
        Console.WriteLine("luminosity:   " + m.get_luminosity().ToString());
        Console.Write("beacon:       ");
        if (m.get_beacon() == YModule.BEACON_ON)
          Console.WriteLine("ON");
        else
          Console.WriteLine("OFF");
        Console.WriteLine("upTime:       " + (m.get_upTime() / 1000 ).ToString()+ " sec");
        Console.WriteLine("USB current:  " + m.get_usbCurrent().ToString() + " mA");
        Console.WriteLine("Logs:\r\n"+ m.get_lastLogs());

      }
    else
      Console.WriteLine(args[0] + " not connected (check identification and USB cable)");
   
   }
  }
}
 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
  class Program
  {
    static void usage()
    { string execname = System.AppDomain.CurrentDomain.FriendlyName;
      Console.WriteLine("Usage:");
      Console.WriteLine("usage: demo <serial or logical name> <new logical name>");
      System.Threading.Thread.Sleep(2500);
      Environment.Exit(0);
    }

    static void Main(string[] args)
    {
      YModule m;
      string errmsg = "";
      string newname;

      if (args.Length != 2) usage();

      if (YAPI.RegisterHub("usb", ref errmsg) !=  YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

      m = YModule.FindModule(args[0]); // use serial or logical name

      if (m.isOnline())
      {
        newname = args[1];
        if (!YAPI.CheckLogicalName(newname))
        {
          Console.WriteLine("Invalid name (" + newname + ")");
          Environment.Exit(0);
        }

        m.set_logicalName(newname);
        m.saveToFlash(); // do not forget this

        Console.Write("Module: serial= " + m.get_serialNumber());
        Console.WriteLine(" / name= " + m.get_logicalName());
      }
      else
        Console.Write("not connected (check identification and USB cable");
    }
  }
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
  class Program
  {
    static void Main(string[] args)
    {
      YModule m;
      string errmsg = "";

      if (YAPI.RegisterHub("usb", ref errmsg) !=  YAPI.SUCCESS)
      {
        Console.WriteLine("RegisterHub error: " + errmsg);
        Environment.Exit(0);
      }

      Console.WriteLine("Device list");
      m = YModule.FirstModule();
      while (m!=null)
      { Console.WriteLine(m.get_serialNumber() + " (" + m.get_productName() + ")");
       m = m.nextModule();
      }

    }
  }
}
 

13.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

14. Using Yocto-MaxiRelay with Delphi

Delphi is a descendent of Turbo-Pascal. Originally, Delphi was produced by Borland, Embarcadero now edits it. The strength of this language resides in its ease of use, as anyone with some notions of the Pascal language can develop a Windows application in next to no time. Its only disadvantage is to cost something36.

Delphi libraries are provided not as VCL components, but directly as source files. These files are compatible with most Delphi versions. 37

To keep them simple, all the examples provided in this documentation are console applications. Obviously, the libraries work in a strictly identical way with VCL applications.

You will soon notice that the Delphi API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.

14.1. Preparation

Go to the Yoctopuce web site and download the Yoctopuce Delphi libraries38. Uncompress everything in a directory of your choice, add the subdirectory sources in the list of directories of Delphi libraries.39

By default, the Yoctopuce Delphi library uses the yapi.dll DLL, all the applications you will create with Delphi must have access to this DLL. The simplest way to ensure this is to make sure yapi.dll is located in the same directory as the executable file of your application.

14.2. Control of the Relay function

Launch your Delphi environment, copy the yapi.dll DLL in a directory, create a new console application in the same directory, and copy-paste the piece of code below:

program helloworld;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api,
  yocto_relay;

procedure usage();
  var
    execname:string;
  begin
    execname := ExtractFileName(paramstr(0));
    WriteLn('Usage:');
    WriteLn(execname + ' <serial_number> <channel> [ ON | OFF ]');
    WriteLn(execname + ' <logical_name> <channel>  [ ON | OFF ]');
    WriteLn(execname + ' any <channel> [ ON | OFF ]');
    WriteLn('Example:');
    WriteLn(execname + ' any 2 ON');
    sleep(2500);
    halt;
  end;

var
 errmsg,target,state,channel:string;
 relay:TYRelay;
 m : TYModule;

begin
  if (paramcount<3) then usage();

  target  :=  UpperCase(paramstr(1));
  channel := paramstr(2);
  state   :=  UpperCase(paramstr(3));

  if (YRegisterHub('usb', errmsg) <> YAPI_SUCCESS)  then
    begin
      writeln('RegisterHub error: ' + errmsg);
      halt;
    end;

  if (target='ANY') then
    begin
      relay :=  YFirstRelay();
      if (relay =nil) then
       begin
         writeln('No module connected (check USB cable)');
         halt;
       end;
      m :=  relay.get_module();
      target := m. get_serialNumber();
     end;

  Writeln('using ' + target);
  relay := YFindRelay(target + '.relay'+channel);

  if (relay.isOnline()) then
    begin
      if (state = 'ON') then  relay.set_output(Y_OUTPUT_ON)
                        else relay.set_output(Y_OUTPUT_OFF);
    end
   else writeln('Module not connected (check identification and USB cable)');

end.

There are only a few really important lines in this sample example. We will look at them in details.

yocto_api and yocto_relay

These two units provide access to the functions allowing you to manage Yoctopuce modules. yocto_api must always be used, yocto_relay is necessary to manage modules containing a relay, such as Yocto-MaxiRelay.

yRegisterHub

The yRegisterHub function initializes the Yoctopuce API and specifies where the modules should be looked for. When used with the parameter 'usb', it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI_SUCCESS and errmsg contains the error message.

yFindRelay

The yFindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can also use logical names, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


relay := yFindRelay("HI8PWER1-123456.relay1");
relay := yFindRelay("HI8PWER1-123456.MyFunction");
relay := yFindRelay("MyModule.relay1");
relay := yFindRelay("MyModule.MyFunction");
relay := yFindRelay("MyFunction");

yFindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by yFindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by yFindRelay switches the relay position to one of its two outputs. The two possible parameter values are Y_STATE_A for output A, and Y_STATE_B for output B.

14.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

program modulecontrol;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api;

const
  serial = 'HI8PWER1-123456'; // use serial number or logical name

procedure refresh(module:Tymodule) ;
  begin
    if (module.isOnline())  then
     begin
       Writeln('');
       Writeln('Serial       : ' + module.get_serialNumber());
       Writeln('Logical name : ' + module.get_logicalName());
       Writeln('Luminosity   : ' + intToStr(module.get_luminosity()));
       Write('Beacon    :');
       if  (module.get_beacon()=Y_BEACON_ON) then Writeln('on')
                                             else Writeln('off');
       Writeln('uptime       : ' + intToStr(module.get_upTime() div 1000)+'s');
       Writeln('USB current  : ' + intToStr(module.get_usbCurrent())+'mA');
       Writeln('Logs         : ');
       Writeln(module.get_lastlogs());
       Writeln('');
       Writeln('r : refresh / b:beacon ON / space : beacon off');
     end
    else Writeln('Module not connected (check identification and USB cable)');
  end;


procedure beacon(module:Tymodule;state:integer);
  begin
    module.set_beacon(state);
    refresh(module);
  end;

var
  module : TYModule;
  c      : char;
  errmsg : string;

begin
  // Setup the API to use local USB devices
  if yRegisterHub('usb', errmsg)<>YAPI_SUCCESS then
  begin
    Write('RegisterHub error: '+errmsg);
    exit;
  end;

  module := yFindModule(serial);
  refresh(module);

  repeat
    read(c);
    case c of
     'r': refresh(module);
     'b': beacon(module,Y_BEACON_ON);
     ' ': beacon(module,Y_BEACON_OFF);
    end;
  until  c = 'x';
end.

Each property xxx of the module can be read thanks to a method of type get_xxxx(), and properties which are not read-only can be modified with the help of the set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash() method. The short example below allows you to modify the logical name of a module.

program savesettings;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api;

const
  serial = 'HI8PWER1-123456'; // use serial number or logical name

var
  module  : TYModule;
  errmsg  : string;
  newname : string;
 
begin
  // Setup the API to use local USB devices
  if yRegisterHub('usb', errmsg)<>YAPI_SUCCESS then
  begin
    Write('RegisterHub error: '+errmsg);
    exit;
  end;

  module := yFindModule(serial);
  if (not(module.isOnline)) then
   begin
     writeln('Module not connected (check identification and USB cable)');
     exit;
   end;

  Writeln('Current logical name : '+module.get_logicalName());
  Write('Enter new name : ');
  Readln(newname);
  if (not(yCheckLogicalName(newname))) then
   begin
     Writeln('invalid logical name');
     exit;
   end;
  module.set_logicalName(newname);
  module.saveToFlash();
 
  Writeln('logical name is now : '+module.get_logicalName());
end.
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not nil. Below a short example listing the connected modules.

program inventory;
{$APPTYPE CONSOLE}
uses
  SysUtils,
  yocto_api;

var
  module : TYModule;
  errmsg : string;

begin
  // Setup the API to use local USB devices
  if yRegisterHub('usb', errmsg)<>YAPI_SUCCESS then
  begin
    Write('RegisterHub error: '+errmsg);
    exit;
  end;

  Writeln('Device list');

  module := yFirstModule();
  while module<>nil  do
   begin
     Writeln( module.get_serialNumber()+' ('+module.get_productName()+')');
     module := module.nextModule();
   end;

end.

14.4. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

15. Using the Yocto-MaxiRelay with Python

Python is an interpreted object oriented language developed by Guido van Rossum. Among its advantages is the fact that it is free, and the fact that it is available for most platforms, Windows as well as UNIX. It is an ideal language to write small scripts on a napkin. The Yoctopuce library is compatible with Python 2.6+ and 3+. It works under Windows, Mac OS X, and Linux, Intel as well as ARM. The library was tested with Python 2.6 and Python 3.2. Python interpreters are available on the Python web site40.

15.1. Source files

The Yoctopuce library classes41 for Python that you will use are provided as source files. Copy all the content of the Sources directory in the directory of your choice and add this directory to the PYTHONPATH environment variable. If you use an IDE to program in Python, refer to its documentation to configure it so that it automatically finds the API source files.

15.2. Dynamic library

A section of the low-level library is written in C, but you should not need to interact directly with it: it is provided as a DLL under Windows, as a .so files under UNIX, and as a .dylib file under Mac OS X. Everything was done to ensure the simplest possible interaction from Python: the distinct versions of the dynamic library corresponding to the distinct operating systems and architectures are stored in the cdll directory. The API automatically loads the correct file during its initialization. You should not have to worry about it.

If you ever need to recompile the dynamic library, its complete source code is located in the Yoctopuce C++ library.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

15.3. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a Python code snipplet to use the Relay function.


[...]

errmsg=YRefParam()
#Get access to your device, connected locally on USB for instance
YAPI.RegisterHub("usb",errmsg)
relay = YRelay.FindRelay("HI8PWER1-123456.relay1")

# Hot-plug is easy: just check that the device is online
if relay.isOnline():
    #Use relay.set_state()
    ...
   
[...]    

Let's look at these lines in more details.

YAPI.RegisterHub

The yAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter "usb", it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from YAPI.SUCCESS and errmsg contains the error message.

YRelay.FindRelay

The YRelay.FindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


relay = YRelay.FindRelay("HI8PWER1-123456.relay1")
relay = YRelay.FindRelay("HI8PWER1-123456.MyFunction")
relay = YRelay.FindRelay("MyModule.relay1")
relay = YRelay.FindRelay("MyModule.MyFunction")
relay = YRelay.FindRelay("MyFunction")

YRelay.FindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by YRelay.FindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by YRelay.FindRelay switches the relay position to one of its two outputs. The two possible parameter values are YRelay.STATE_A for output A, and YRelay.STATE_B for output B.

A real example

Launch Python and open the corresponding sample script provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.

#!/usr/bin/python
import os,sys
# -*- coding: utf-8 -*-
from yocto_api import *
from yocto_relay import *

def usage():
    scriptname = os.path.basename(sys.argv[0])
    print("Usage:")
    print(scriptname + ' <serial_number> <channel> [ ON | OFF ]')
    print(scriptname + ' <logical_name> <channel>  [ ON | OFF ]')
    print(scriptname + ' any <channel> [ ON | OFF ]')
    print('Example:')
    print(scriptname + ' any 2 ON')
    sys.exit()

def die(msg):
    sys.exit(msg+' (check USB cable)')

if len(sys.argv)<3 :  usage()

target=sys.argv[1].upper()
channel=sys.argv[2]
state=sys.argv[3].upper()

# Setup the API to use local USB devices
errmsg=YRefParam()
if YAPI.RegisterHub("usb", errmsg)!= YAPI.SUCCESS:
    sys.exit("init error"+errmsg.value)

if target=='ANY':
    # retreive any Relay then find its serial #
    relay = YRelay.FirstRelay()
    if relay is None : die('No module connected')
    m=relay.get_module()
    target = m.get_serialNumber()

print('using ' + target)
relay = YRelay.FindRelay(target + '.relay'+channel)

if not(relay.isOnline()):die('device not connected')

if relay.isOnline():
    if state == 'ON' :
        relay.set_output(YRelay.OUTPUT_ON)
    else:
        relay.set_output(YRelay.OUTPUT_OFF)
else:
    die('Module not connected')

15.4. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os,sys
from yocto_api import *


def usage():
    sys.exit("usage: demo <serial or logical name> [ON/OFF]")

errmsg =YRefParam()
if YAPI.RegisterHub("usb", errmsg) !=  YAPI.SUCCESS:
    sys.exit("RegisterHub error: " + str(errmsg))

if len(sys.argv)<2 : usage()

m = YModule.FindModule(sys.argv[1]) ## use serial or logical name

if m.isOnline():
    if len(sys.argv) > 2:
        if sys.argv[2].upper() == "ON" :  m.set_beacon(YModule.BEACON_ON)
        if sys.argv[2].upper() == "OFF" : m.set_beacon(YModule.BEACON_OFF)

    print("serial:       " + m.get_serialNumber())
    print("logical name: " + m.get_logicalName())
    print("luminosity:   " + str(m.get_luminosity()))
    if m.get_beacon() == YModule.BEACON_ON:
        print("beacon:       ON")
    else:
        print("beacon:       OFF")
    print("upTime:       " + str(m.get_upTime()/1000)+" sec")
    print("USB current:  " + str(m.get_usbCurrent())+" mA")
    print("logs:\n" + m.get_lastLogs())    
else:
    print(sys.argv[1] + " not connected (check identification and USB cable)")



 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os,sys
from yocto_api import *

def usage():
    sys.exit("usage: demo <serial or logical name> <new logical name>")

if len(sys.argv) != 3 :  usage()

errmsg =YRefParam()
if YAPI.RegisterHub("usb", errmsg) !=  YAPI.SUCCESS:
    sys.exit("RegisterHub error: " + str(errmsg))

m = YModule.FindModule(sys.argv[1]) # use serial or logical name

if m.isOnline():
    newname = sys.argv[2]
    if not YAPI.CheckLogicalName(newname):
        sys.exit("Invalid name (" + newname + ")")
    m.set_logicalName(newname)
    m.saveToFlash()  # do not forget this
    print ("Module: serial= " + m.get_serialNumber()+" / name= " + m.get_logicalName())
else:
    sys.exit("not connected (check identification and USB cable")

 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

#!/usr/bin/python
# -*- coding: utf-8 -*-
import os,sys

from yocto_api import *

errmsg=YRefParam()

# Setup the API to use local USB devices
if YAPI.RegisterHub("usb", errmsg)!= YAPI.SUCCESS:
    sys.exit("init error"+str(errmsg))

print('Device list')

module = YModule.FirstModule()
while module is not None:
     print(module.get_serialNumber()+' ('+module.get_productName()+')')
     module = module.nextModule()
 

15.5. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.

The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:

As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions() function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state() method returns a Y_STATE_INVALID value, a get_currentValue method returns a Y_CURRENTVALUE_INVALID value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is YAPI_SUCCESS if everything went well, and a different error code in case of failure.

When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType() and errMessage() methods. Their returned values contain the same information as in the exceptions when they are active.

16. Using the Yocto-MaxiRelay with Java

Java is an object oriented language created by Sun Microsystem. Beside being free, its main strength is its portability. Unfortunately, this portability has an excruciating price. In Java, hardware abstraction is so high that it is almost impossible to work directly with the hardware. Therefore, the Yoctopuce API does not support native mode in regular Java. The Java API needs a Virtual Hub to communicate with Yoctopuce devices.

16.1. Getting ready

Go to the Yoctopuce web site and download the following items:

The library is available as source files as well as a jar file. Decompress the library files in a folder of your choice, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.

In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.

16.2. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a Java code snippet to use the Relay function.


[...]

// Get access to your device, connected locally on USB for instance
YAPI.RegisterHub("127.0.0.1");
relay = YRelay.FindRelay("HI8PWER1-123456.relay1");

// Hot-plug is easy: just check that the device is online
if (relay.isOnline())
   { //Use relay.set_state()
     ...
   }

[...]

Let us look at these lines in more details.

YAPI.RegisterHub

The yAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. The parameter is the address of the Virtual Hub able to see the devices. If the initialization does not succeed, an exception is thrown.

YRelay.FindRelay

The YRelay.FindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


relay = YRelay.FindRelay("HI8PWER1-123456.relay1")
relay = YRelay.FindRelay("HI8PWER1-123456.MyFunction")
relay = YRelay.FindRelay("MyModule.relay1")
relay = YRelay.FindRelay("MyModule.MyFunction")
relay = YRelay.FindRelay("MyFunction")

YRelay.FindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by YRelay.FindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by YRelay.FindRelay switches the relay position to one of its two outputs. The two possible parameter values are YRelay.STATE_A for output A, and YRelay.STATE_B for output B.

A real example

Launch you Java environment and open the corresponding sample project provided in the directory Examples/Doc-GettingStarted-Yocto-MaxiRelay of the Yoctopuce library.

In this example, you will recognize the functions explained above, but this time used with all the side materials needed to make it work nicely as a small demo.

import com.yoctopuce.YoctoAPI.*;

public class Demo {

    public static void main(String[] args)   {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }

        String serial = "";
        if (args.length > 0) {
            serial = args[0];
        } else {
            YRelay tmp = YRelay.FirstRelay();
            if (tmp == null) {
                System.out.println("No module connected (check USB cable)");
                System.exit(1);
            }
            try {
                serial = tmp.module().get_serialNumber();
            } catch (YAPI_Exception ex) {
                System.out.println("No module connected (check USB cable)");
                System.exit(1);
            }
        }

        System.out.println("We will use");

        try {

            System.out.println("Switch on all output");
            for (int channel = 1; channel < 9; channel++) {
                YRelay relay = YRelay.FindRelay(serial + ".relay" + channel);
                relay.set_output(YRelay.OUTPUT_ON);
                YAPI.Sleep(100);
            }
            YAPI.Sleep(500);
            System.out.println("Switch off all output");
            for (int channel = 1; channel < 9; channel++) {
                YRelay relay = YRelay.FindRelay(serial + ".relay" + channel);
                relay.set_output(YRelay.OUTPUT_OFF);
                YAPI.Sleep(100);
            }
        } catch (YAPI_Exception ex) {
            System.out.println("Module not connected (check identification and USB cable)");
        }

        YAPI.FreeAPI();

    }
}
 

16.3. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.


import com.yoctopuce.YoctoAPI.*;
import java.util.logging.Level;
import java.util.logging.Logger;

public class Demo {

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }
        System.out.println("usage: demo [serial or logical name] [ON/OFF]");

        YModule module;
        if (args.length == 0) {
            module = YModule.FirstModule();
            if (module == null) {
                System.out.println("No module connected (check USB cable)");
                System.exit(1);
            }
        } else {
            module = YModule.FindModule(args[0]);  // use serial or logical name
        }

        try {
            if (args.length > 1) {
                if (args[1].equalsIgnoreCase("ON")) {
                    module.setBeacon(YModule.BEACON_ON);
                } else {
                    module.setBeacon(YModule.BEACON_OFF);
                }
            }
            System.out.println("serial:       " + module.get_serialNumber());
            System.out.println("logical name: " + module.get_logicalName());
            System.out.println("luminosity:   " + module.get_luminosity());
            if (module.get_beacon() == YModule.BEACON_ON) {
                System.out.println("beacon:       ON");
            } else {
                System.out.println("beacon:       OFF");
            }
            System.out.println("upTime:       " + module.get_upTime() / 1000 + " sec");
            System.out.println("USB current:  " + module.get_usbCurrent() + " mA");
            System.out.println("logs:\n" + module.get_lastLogs());
        } catch (YAPI_Exception ex) {
            System.out.println(args[1] + " not connected (check identification and USB cable)");
        }
        YAPI.FreeAPI();
    }
}
 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

import com.yoctopuce.YoctoAPI.*;

public class Demo {

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }

        if (args.length != 2) {
            System.out.println("usage: demo <serial or logical name> <new logical name>");
            System.exit(1);
        }

        YModule m;
        String newname;

        m = YModule.FindModule(args[0]); // use serial or logical name

        try {
            newname = args[1];
            if (!YAPI.CheckLogicalName(newname))
                {
                    System.out.println("Invalid name (" + newname + ")");
                    System.exit(1);
                }

            m.set_logicalName(newname);
            m.saveToFlash(); // do not forget this

            System.out.println("Module: serial= " + m.get_serialNumber());
            System.out.println(" / name= " + m.get_logicalName());
        } catch (YAPI_Exception ex) {
            System.out.println("Module " + args[0] + "not connected (check identification and USB cable)");
            System.out.println(ex.getMessage());
            System.exit(1);
        }

        YAPI.FreeAPI();
    }
}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

import com.yoctopuce.YoctoAPI.*;

public class Demo {

    public static void main(String[] args)
    {
        try {
            // setup the API to use local VirtualHub
            YAPI.RegisterHub("127.0.0.1");
        } catch (YAPI_Exception ex) {
            System.out.println("Cannot contact VirtualHub on 127.0.0.1 (" + ex.getLocalizedMessage() + ")");
            System.out.println("Ensure that the VirtualHub application is running");
            System.exit(1);
        }

        System.out.println("Device list");
        YModule module = YModule.FirstModule();
        while (module != null) {
            try {
                System.out.println(module.get_serialNumber() + " (" + module.get_productName() + ")");
            } catch (YAPI_Exception ex) {
                break;
            }
            module = module.nextModule();
        }

        YAPI.FreeAPI();
    }
}
 

16.4. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software.

In the Java API, error handling is implemented with exceptions. Therefore you must catch and handle correctly all exceptions that might be thrown by the API if you do not want your software to crash as soon as you unplug a device.

17. Using the Yocto-MaxiRelay with Android

To tell the truth, Android is not a programming language, it is an operating system developed by Google for mobile appliances such as smart phones and tablets. But it so happens that under Android everything is programmed with the same programming language: Java. Nevertheless, the programming paradigms and the possibilities to access the hardware are slightly different from classical Java, and this justifies a separate chapter on Android programming.

17.1. Native access and VirtualHub

In the opposite to the classical Java API, the Java for Android API can access USB modules natively. However, as there is no VirtualHub running under Android, it is not possible to remotely control Yoctopuce modules connected to a machine under Android. Naturally, the Java for Android API remains perfectly able to connect itself to a VirtualHub running on another OS.

17.2. Getting ready

Go to the Yoctopuce web site and download the Java for Android programming library44. The library is available as source files, and also as a jar file. Connect your modules, decompress the library files in the directory of your choice, and configure your Android programming environment so that it can find them.

To keep them simple, all the examples provided in this documentation are snippets of Android applications. You must integrate them in your own Android applications to make them work. However, your can find complete applications in the examples provided with the Java for Android library.

17.3. Compatibility

In an ideal world, you would only need to have a smart phone running under Android to be able to make Yoctopuce modules work. Unfortunately, it is not quite so in the real world. A machine running under Android must fulfil to a few requirements to be able to manage Yoctopuce USB modules natively.

Android 4.x

Android 4.0 (api 14) and following are officially supported. Theoretically, support of USB host functions since Android 3.1. But be aware that the Yoctopuce Java for Android API is regularly tested only from Android 4 onwards.

USB host support

Naturally, not only must your machine have a USB port, this port must also be able to run in host mode. In host mode, the machine literally takes control of the devices which are connected to it. The USB ports of a desktop computer, for example, work in host mode. The opposite of the host mode is the device mode. USB keys, for instance, work in device mode: they must be controlled by a host. Some USB ports are able to work in both modes, they are OTG (On The Go) ports. It so happens that many mobile devices can only work in device mode: they are designed to be connected to a charger or a desktop computer, and nothing else. It is therefore highly recommended to pay careful attention to the technical specifications of a product working under Android before hoping to make Yoctopuce modules work with it.

Unfortunately, having a correct version of Android and USB ports working in host mode is not enough to guaranty that Yoctopuce modules will work well under Android. Indeed, some manufacturers configure their Android image so that devices other than keyboard and mass storage are ignored, and this configuration is hard to detect. As things currently stand, the best way to know if a given Android machine works with Yoctopuce modules consists in trying.

Supported hardware

The library is tested and validated on the following machines:

If your Android machine is not able to control Yoctopuce modules natively, you still have the possibility to remotely control modules driven by a VirtualHub on another OS, or a YoctoHub 45.

17.4. Activating the USB port under Android

By default, Android does not allow an application to access the devices connected to the USB port. To enable your application to interact with a Yoctopuce module directly connected on your tablet on a USB port, a few additional steps are required. If you intend to interact only with modules connected on another machine through the network, you can ignore this section.

In your AndroidManifest.xml, you must declare using the "USB Host" functionality by adding the <uses-feature android:name="android.hardware.usb.host" /> tag in the manifest section.


<manifest ...>
    ...
    <uses-feature android:name="android.hardware.usb.host" />;
    ...
</manifest>

When first accessing a Yoctopuce module, Android opens a window to inform the user that the application is going to access the connected module. The user can deny or authorize access to the device. If the user authorizes the access, the application can access the connected device as long as it stays connected. To enable the Yoctopuce library to correctly manage these authorizations, your must provide a pointer on the application context by calling the EnableUSBHost method of the YAPI class before the first USB access. This function takes as arguments an object of the android.content.Context class (or of a subclass). As the Activity class is a subclass of Context, it is simpler to call YAPI.EnableUSBHost(this); in the method onCreate of your application. If the object passed as parameter is not of the correct type, a YAPI_Exception exception is generated.


...
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    try {
                // Pass the application Context to the Yoctopuce Library
        YAPI.EnableUSBHost(this);
        } catch (YAPI_Exception e) {
                Log.e("Yocto",e.getLocalizedMessage());
        }
}
...

Autorun

It is possible to register your application as a default application for a USB module. In this case, as soon as a module is connected to the system, the application is automatically launched. You must add <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"/> in the section <intent-filter> of the main activity. The section <activity> must have a pointer to an XML file containing the list of USB modules which can run the application.


<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    ...
    <uses-feature android:name="android.hardware.usb.host" />
    ...
    <application ... >
        <activity
            android:name=".MainActivity" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
                android:resource="@xml/device_filter" />
        </activity>
    </application>

</manifest>

The XML file containing the list of modules allowed to run the application must be saved in the res/xml directory. This file contains a list of USB vendorId and deviceID in decimal. The following example runs the application as soon as a Yocto-Relay or a YoctoPowerRelay is connected. You can find the vendorID and the deviceID of Yoctopuce modules in the characteristics section of the documentation.


<?xml version="1.0" encoding="utf-8"?>

<resources>
    <usb-device vendor-id="9440" product-id="12" />
    <usb-device vendor-id="9440" product-id="13" />
</resources>

17.5. Control of the Relay function

A few lines of code are enough to use a Yocto-MaxiRelay. Here is the skeleton of a Java code snippet to use the Relay function.


[...]

// Retrieving the object representing the module (connected here locally by USB)
YAPI.EnableUSBHost(this);
YAPI.RegisterHub("usb");
relay = YRelay.FindRelay("HI8PWER1-123456.relay1");

// Hot-plug is easy: just check that the device is online
if (relay.isOnline())
   { //Use relay.set_state()
     ...
   }

[...]

Let us look at these lines in more details.

YAPI.EnableUSBHost

The YAPI.EnableUSBHost function initializes the API with the Context of the current application. This function takes as argument an object of the android.content.Context class (or of a subclass). If you intend to connect your application only to other machines through the network, this function is facultative.

YAPI.RegisterHub

The yAPI.RegisterHub function initializes the Yoctopuce API and indicates where the modules should be looked for. The parameter is the address of the virtual hub able to see the devices. If the string "usb" is passed as parameter, the API works with modules locally connected to the machine. If the initialization does not succeed, an exception is thrown.

YRelay.FindRelay

The YRelay.FindRelay function allows you to find a relay from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-MaxiRelay module with serial number HI8PWER1-123456 which you have named "MyModule", and for which you have given the relay1 function the name "MyFunction". The following five calls are strictly equivalent, as long as "MyFunction" is defined only once.


relay = YRelay.FindRelay("HI8PWER1-123456.relay1")
relay = YRelay.FindRelay("HI8PWER1-123456.MyFunction")
relay = YRelay.FindRelay("MyModule.relay1")
relay = YRelay.FindRelay("MyModule.MyFunction")
relay = YRelay.FindRelay("MyFunction")

YRelay.FindRelay returns an object which you can then use at will to control the relay.

isOnline

The isOnline() method of the object returned by YRelay.FindRelay allows you to know if the corresponding module is present and in working order.

set_state

The set_state() method of the objet returned by YRelay.FindRelay switches the relay position to one of its two outputs. The two possible parameter values are YRelay.STATE_A for output A, and YRelay.STATE_B for output B.

A real example

Launch you Java environment and open the corresponding sample project provided in the directory Examples//Doc-Examples of the Yoctopuce library.

In this example, you can recognize the functions explained above, but this time used with all the side materials needed to make it work nicely as a small demo.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YRelay;

public class GettingStarted_Yocto_MaxiRelay extends Activity implements OnItemSelectedListener
{

    private YRelay relay = null;
    private ArrayAdapter<String> aa;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.gettingstarted_yocto_maxirelay);
        Spinner my_spin = (Spinner) findViewById(R.id.spinner1);
        my_spin.setOnItemSelectedListener(this);
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        my_spin.setAdapter(aa);
    }

    @Override
    protected void onStart()
    {
        super.onStart();

        try {
            aa.clear();
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
            YRelay r = YRelay.FirstRelay();
            while (r != null) {
                String hwid = r.get_hardwareId();
                aa.add(hwid);
                r = r.nextRelay();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        // refresh Spinner with detected relay
        aa.notifyDataSetChanged();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
    {
        String hwid = parent.getItemAtPosition(pos).toString();
        relay = YRelay.FindRelay(hwid);
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0)
    {
    }

    /** Called when the user touches the button State A */
    public void setRelayOn(View view)
    {
        if (relay != null)
            try {
                relay.set_output(YRelay.OUTPUT_ON);
            } catch (YAPI_Exception e) {
                e.printStackTrace();
            }
    }

    /** Called when the user touches the button State B */
    public void setRelayOff(View view)
    {
        if (relay != null)
            try {
                relay.set_output(YRelay.OUTPUT_OFF);
            } catch (YAPI_Exception e) {
                e.printStackTrace();
            }
    }
}
 

17.6. Control of the module part

Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Switch;
import android.widget.TextView;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YModule;

public class ModuleControl extends Activity implements OnItemSelectedListener
{

    private ArrayAdapter<String> aa;
    private YModule module = null;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.modulecontrol);
        Spinner my_spin = (Spinner) findViewById(R.id.spinner1);
        my_spin.setOnItemSelectedListener(this);
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        my_spin.setAdapter(aa);
    }

    @Override
    protected void onStart()
    {
        super.onStart();

        try {
            aa.clear();
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
            YModule r = YModule.FirstModule();
            while (r != null) {
                String hwid = r.get_hardwareId();
                aa.add(hwid);
                r = r.nextModule();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        // refresh Spinner with detected relay
        aa.notifyDataSetChanged();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

    private void DisplayModuleInfo()
    {
        TextView field;
        if (module == null)
            return;
        try {
            field = (TextView) findViewById(R.id.serialfield);
            field.setText(module.getSerialNumber());
            field = (TextView) findViewById(R.id.logicalnamefield);
            field.setText(module.getLogicalName());
            field = (TextView) findViewById(R.id.luminosityfield);
            field.setText(String.format("%d%%", module.getLuminosity()));
            field = (TextView) findViewById(R.id.uptimefield);
            field.setText(module.getUpTime() / 1000 + " sec");
            field = (TextView) findViewById(R.id.usbcurrentfield);
            field.setText(module.getUsbCurrent() + " mA");
            Switch sw = (Switch) findViewById(R.id.beaconswitch);
            Log.d("switch", "beacon" + module.get_beacon());
            sw.setChecked(module.getBeacon() == YModule.BEACON_ON);
            field = (TextView) findViewById(R.id.logs);
            field.setText(module.get_lastLogs());

        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
    {
        String hwid = parent.getItemAtPosition(pos).toString();
        module = YModule.FindModule(hwid);
        DisplayModuleInfo();
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0)
    {
    }

    public void refreshInfo(View view)
    {
        DisplayModuleInfo();
    }

    public void toggleBeacon(View view)
    {
        if (module == null)
            return;
        boolean on = ((Switch) view).isChecked();

        try {
            if (on) {
                module.setBeacon(YModule.BEACON_ON);
            } else {
                module.setBeacon(YModule.BEACON_OFF);
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }
}
 

Each property xxx of the module can be read thanks to a method of type YModule.get_xxxx(), and properties which are not read-only can be modified with the help of the YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.

Changing the module settings

When you want to modify the settings of a module, you only need to call the corresponding YModule.set_xxx() function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the YModule.saveToFlash() method. Inversely, it is possible to force the module to forget its current settings by using the YModule.revertFromFlash() method. The short example below allows you to modify the logical name of a module.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YModule;

public class SaveSettings extends Activity implements OnItemSelectedListener
{

    private ArrayAdapter<String> aa;
    private YModule module = null;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.savesettings);
        Spinner my_spin = (Spinner) findViewById(R.id.spinner1);
        my_spin.setOnItemSelectedListener(this);
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        my_spin.setAdapter(aa);
    }

    @Override
    protected void onStart()
    {
        super.onStart();

        try {
            aa.clear();
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
            YModule r = YModule.FirstModule();
            while (r != null) {
                String hwid = r.get_hardwareId();
                aa.add(hwid);
                r = r.nextModule();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        // refresh Spinner with detected relay
        aa.notifyDataSetChanged();
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

    private void DisplayModuleInfo()
    {
        TextView field;
        if (module == null)
            return;
        try {
            YAPI.UpdateDeviceList();// fixme
            field = (TextView) findViewById(R.id.logicalnamefield);
            field.setText(module.getLogicalName());
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int pos, long id)
    {
        String hwid = parent.getItemAtPosition(pos).toString();
        module = YModule.FindModule(hwid);
        DisplayModuleInfo();
    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0)
    {
    }

    public void saveName(View view)
    {
        if (module == null)
            return;

        EditText edit = (EditText) findViewById(R.id.newname);
        String newname = edit.getText().toString();
        try {
            if (!YAPI.CheckLogicalName(newname)) {
                Toast.makeText(getApplicationContext(), "Invalid name (" + newname + ")", Toast.LENGTH_LONG).show();
                return;
            }
            module.set_logicalName(newname);
            module.saveToFlash(); // do not forget this
            edit.setText("");
        } catch (YAPI_Exception ex) {
            ex.printStackTrace();
        }
        DisplayModuleInfo();
    }

}
 

Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the YModule.saveToFlash() function only 100000 times in the life of the module. Make sure you do not call this function within a loop.

Listing the modules

Obtaining the list of the connected modules is performed with the YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null. Below a short example listing the connected modules.

package com.yoctopuce.doc_examples;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.yoctopuce.YoctoAPI.YAPI;
import com.yoctopuce.YoctoAPI.YAPI_Exception;
import com.yoctopuce.YoctoAPI.YModule;

public class Inventory extends Activity
{

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.inventory);
    }

    public void refreshInventory(View view)
    {
        LinearLayout layout = (LinearLayout) findViewById(R.id.inventoryList);
        layout.removeAllViews();

        try {
            YAPI.UpdateDeviceList();
            YModule module = YModule.FirstModule();
            while (module != null) {
                String line = module.get_serialNumber() + " (" + module.get_productName() + ")";
                TextView tx = new TextView(this);
                tx.setText(line);
                layout.addView(tx);
                module = module.nextModule();
            }
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onStart()
    {
        super.onStart();
        try {
            YAPI.EnableUSBHost(this);
            YAPI.RegisterHub("usb");
        } catch (YAPI_Exception e) {
            e.printStackTrace();
        }
        refreshInventory(null);
    }

    @Override
    protected void onStop()
    {
        super.onStop();
        YAPI.FreeAPI();
    }

}
 

17.7. Error handling

When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.

The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run. This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline and which could crash the software.

In the Java API for Android, error handling is implemented with exceptions. Therefore you must catch and handle correctly all exceptions that might be thrown by the API if you do not want your software to crash soon as you unplug a device.

18. Advanced programming

The preceding chapters have introduced, in each available language, the basic programming functions which can be used with your Yocto-MaxiRelay module. This chapter presents in a more generic manner a more advanced use of your module. Examples are provided in the language which is the most popular among Yoctopuce customers, that is C#. Nevertheless, you can find complete examples illustrating the concepts presented here in the programming libraries of each language.

To remain as concise as possible, examples provided in this chapter do not perform any error handling. Do not copy them "as is" in a production application.

18.1. Event programming

The methods to manage Yoctopuce modules which we presented to you in preceding chapters were polling functions, consisting in permanently asking the API if something had changed. While easy to understand, this programming technique is not the most efficient, nor the most reactive. Therefore, the Yoctopuce programming API also provides an event programming model. This technique consists in asking the API to signal by itself the important changes as soon as they are detected. Each time a key parameter is modified, the API calls a callback function which you have defined in advance.

Detecting module arrival and departure

Hot-plug management is important when you work with USB modules because, sooner or later, you will have to connect or disconnect a module when your application is running. The API is designed to manage module unexpected arrival or departure in a transparent way. But your application must take this into account if it wants to avoid pretending to use a disconnected module.

Event programming is particularly useful to detect module connection/disconnection. Indeed, it is simpler to be told of new connections rather than to have to permanently list the connected modules to deduce which ones just arrived and which ones left. To be warned as soon as a module is connected, you need three pieces of code.

The callback

The callback is the function which is called each time a new Yoctopuce module is connected. It takes as parameter the relevant module.


 static void deviceArrival(YModule m)
{
  Console.WriteLine("New module  : " + m.get_serialNumber());
}

Initialization

You must then tell the API that it must call the callback when a new module is connected.


YAPI.RegisterDeviceArrivalCallback(deviceArrival);

Note that if modules are already connected when the callback is registered, the callback is called for each of the already connected modules.

Triggering callbacks

A classis issue of callback programming is that these callbacks can be triggered at any time, including at times when the main program is not ready to receive them. This can have undesired side effects, such as dead-locks and other race conditions. Therefore, in the Yoctopuce API, module arrival/departure callbacks are called only when the UpdateDeviceList() function is running. You only need to call UpdateDeviceList() at regular intervals from a timer or from a specific thread to precisely control when the calls to these callbacks happen:


// waiting loop managing callbacks
while (true)
{
    // module arrival / departure callback
    YAPI.UpdateDeviceList(ref errmsg);
    // non active waiting time managing other callbacks
    YAPI.Sleep(500, ref errmsg);
}

In a similar way, it is possible to have a callback when a module is disconnected. You can find a complete example implemented in your favorite programming language in the Examples/Prog-EventBased directory of the corresponding library.

Be aware that in most programming languages, callbacks must be global procedures, and not methods. If you wish for the callback to call the method of an object, define your callback as a global procedure which then calls your method.

19. Using with unsupported languages

Yoctopuce modules can be driven from most common programming languages. New languages are regularly added, depending on the interest expressed by Yoctopuce product users. Nevertheless, some languages are not, and will never be, supported by Yoctopuce. There can be several reasons for this: compilers which are not available anymore, unadapted environments, etc.

However, there are alternative methods to access Yoctopuce modules from an unsupported programming language.

19.1. Command line

The easiest method to drive Yoctopuce modules from an unsupported programming language is to use the command line API through system calls. The command line API is in fact made of a group of small executables which are easy to call. Their output is also easy to analyze. As most programming languages allow you to make system calls, the issue is solved with a few lines of code.

However, if the command line API is the easiest solution, it is neither the fastest nor the most efficient. For each call, the executable must initialize its own API and make an inventory of USB connected modules. This requires about one second per call.

19.2. VirtualHub and HTTP GET

The VirtualHub is available on almost all current platforms. It is generally used as a gateway to provide access to Yoctopuce modules from languages which prevent direct access to hardware layers of a computer (JavaScript, PHP, Java, ...).

In fact, the VirtualHub is a small web server able to route HTTP requests to Yoctopuce modules. This means that if you can make an HTTP request from your programming language, you can drive Yoctopuce modules, even if this language is not officially supported.

REST interface

At a low level, the modules are driven through a REST API. Thus, to control a module, you only need to perform appropriate requests on the VirtualHub. By default, the VirtualHub HTTP port is 4444.

An important advantage of this technique is that preliminary tests are very easy to implement. You only need a VirtualHub and a simple web browser. If you copy the following URL in your preferred browser, while the VirtualHub is running, you obtain the list of the connected modules.


http://127.0.0.1:4444/api/services/whitePages.txt

Note that the result is displayed as text, but if you request whitePages.xml, you obtain an XML result. Likewise, whitePages.json allows you to obtain a JSON result. The html extension even allows you to display a rough interface where you can modify values in real time. The whole REST API is available in these different formats.

Driving a module through the REST interface

Each Yoctopuce module has its own REST interface, available in several variants. Let us imagine a Yocto-MaxiRelay with the HI8PWER1-12345 serial number and the myModule logical name. The following URL allows you to know the state of the module.


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/api/module.txt

You can naturally also use the module logical name rather than its serial number.


http://127.0.0.1:4444/byName/myModule/api/module.txt

To retrieve the value of a module property, simply add the name of the property below module. For example, if you want to know the signposting led luminosity, send the following request:


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/api/module/luminosity

To change the value of a property, modify the corresponding attribute. Thus, to modify the luminosity, send the following request:


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/api/module?luminosity=100

Driving the module functions through the REST interface

The module functions can be manipulated in the same way. To know the state of the relay function, build the following URL:


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/api/relay.txt

Note that if you can use logical names for the modules instead of their serial number, you cannot use logical names for functions. Only hardware names are authorized to access functions.

You can retrieve a module function attribute in a way rather similar to that used with the modules. For example:


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/api/relay/logicalName

Rather logically, attributes can be modified in the same manner.


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/api/relay?logicalName=myFunction

You can find the list of available attributes for your Yocto-MaxiRelay at the beginning of the Programming chapter.

Accessing Yoctopuce data logger through the REST interface

This section only applies to devices with a built-in data logger.

The preview of all recorded data streams can be retrieved in JSON format using the following URL:


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/dataLogger.json

Individual measures for any given stream can be obtained by appending the desired function identifier as well as start time of the stream:


http://127.0.0.1:4444/bySerial/HI8PWER1-12345/dataLogger.json?id=relay&utc=1389801080

19.3. Using dynamic libraries

The low level Yoctopuce API is available under several formats of dynamic libraries written in C. The sources are available with the C++ API. If you use one of these low level libraries, you do not need the VirtualHub anymore.

FilenamePlatform
libyapi.dylibMax OS X
libyapi-amd64.soLinux Intel (64 bits)
libyapi-armel.soLinux ARM EL
libyapi-armhf.soLinux ARM HL
libyapi-i386.soLinux Intel (32 bits)
yapi64.dllWindows (64 bits)
yapi.dllWindows (32 bits)

These dynamic libraries contain all the functions necessary to completely rebuild the whole high level API in any language able to integrate these libraries. This chapter nevertheless restrains itself to describing basic use of the modules.

Driving a module

The three essential functions of the low level API are the following:


int yapiInitAPI(int connection_type, char *errmsg);
int yapiUpdateDeviceList(int forceupdate, char *errmsg);
int yapiHTTPRequest(char *device, char *request, char* buffer,int buffsize,int *fullsize, char *errmsg);

The yapiInitAPI function initializes the API and must be called once at the beginning of the program. For a USB type connection, the connection_type parameter takes value 1. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

The yapiUpdateDeviceList manages the inventory of connected Yoctopuce modules. It must be called at least once. To manage hot plug and detect potential newly connected modules, this function must be called at regular intervals. The forceupdate parameter must take value 1 to force a hardware scan. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

Finally, the yapiHTTPRequest function sends HTTP requests to the module REST API. The device parameter contains the serial number or the logical name of the module which you want to reach. The request parameter contains the full HTTP request (including terminal line breaks). buffer points to a character buffer long enough to contain the answer. buffsize is the size of the buffer. fullsize is a pointer to an integer to which will be assigned the actual size of the answer. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

The format of the requests is the same as the one described in the VirtualHub et HTTP GET section. All the character strings used by the API are strings made of 8-bit characters: Unicode and UTF8 are not supported.

The resutlt returned in the buffer variable respects the HTTP protocol. It therefore includes an HTTP header. This header ends with two empty lines, that is a sequence of four ASCII characters 13, 10, 13, 10.

Here is a sample program written in pascal using the yapi.dll DLL to read and then update the luminosity of a module.


// Dll functions import
function  yapiInitAPI(mode:integer;
                      errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiInitAPI';
function  yapiUpdateDeviceList(force:integer;errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiUpdateDeviceList';
function  yapiHTTPRequest(device:pansichar;url:pansichar; buffer:pansichar;
                      buffsize:integer;var fullsize:integer;
                      errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiHTTPRequest';

var
 errmsgBuffer  : array [0..256] of ansichar;
 dataBuffer    : array [0..1024] of ansichar;
 errmsg,data   : pansichar;
 fullsize,p    : integer;

const
  serial      = 'HI8PWER1-12345';
  getValue = 'GET /api/module/luminosity HTTP/1.1'#13#10#13#10;
  setValue = 'GET /api/module?luminosity=100 HTTP/1.1'#13#10#13#10;

begin
  errmsg  :=  @errmsgBuffer;
  data    :=  @dataBuffer;
  // API  initialization
  if(yapiInitAPI(1,errmsg)<0) then
   begin
    writeln(errmsg);
    halt;
  end;

  // forces a device inventory
  if( yapiUpdateDeviceList(1,errmsg)<0) then
    begin
     writeln(errmsg);
     halt;
   end;

  // requests the  module luminosity
  if (yapiHTTPRequest(serial,getValue,data,sizeof(dataBuffer),fullsize,errmsg)<0) then
   begin
     writeln(errmsg);
     halt;
   end;

  // searches for the HTTP header end
  p := pos(#13#10#13#10,data);

  // displays the response minus the HTTP header
  writeln(copy(data,p+4,length(data)-p-3));

  // changes the luminosity
  if (yapiHTTPRequest(serial,setValue,data,sizeof(dataBuffer),fullsize,errmsg)<0) then
   begin
     writeln(errmsg);
     halt;
   end;

end.

Module inventory

To perform an inventory of Yoctopuce modules, you need two functions from the dynamic library:


 int yapiGetAllDevices(int *buffer,int maxsize,int *neededsize,char *errmsg);
 int yapiGetDeviceInfo(int devdesc,yDeviceSt *infos, char *errmsg);

The yapiGetAllDevices function retrieves the list of all connected modules as a list of handles. buffer points to a 32-bit integer array which contains the returned handles. maxsize is the size in bytes of the buffer. To neededsize is assigned the necessary size to store all the handles. From this, you can deduce either the number of connected modules or that the input buffer is too small. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.

The yapiGetDeviceInfo function retrieves the information related to a module from its handle. devdesc is a 32-bit integer representing the module and which was obtained through yapiGetAllDevices. infos points to a data structure in which the result is stored. This data structure has the following format:

Name TypeSize (bytes)Description
vendorid int4Yoctopuce USB ID
deviceid int4Module USB ID
devrelease int4Module version
nbinbterfaces int4Number of USB interfaces used by the module
manufacturer char[]20Yoctopuce (null terminated)
productname char[]28Model (null terminated)
serial char[]20Serial number (null terminated)
logicalname char[]20Logical name (null terminated)
firmware char[]22Firmware version (null terminated)
beacon byte1Beacon state (0/1)

The errmsg parameter must point to a 255 character buffer to retrieve a potential error message.

Here is a sample program written in pascal using the yapi.dll DLL to list the connected modules.


// device description structure
type yDeviceSt = packed record
   vendorid        : word;
   deviceid        : word;
   devrelease      : word;
   nbinbterfaces   : word;
   manufacturer    : array [0..19] of ansichar;
   productname     : array [0..27] of ansichar;
   serial          : array [0..19] of ansichar;
   logicalname     : array [0..19] of ansichar;
   firmware        : array [0..21] of ansichar;
   beacon          : byte;
 end;

// Dll function import
function  yapiInitAPI(mode:integer;
                      errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiInitAPI';

function  yapiUpdateDeviceList(force:integer;errmsg : pansichar):integer;cdecl;
                      external 'yapi.dll' name 'yapiUpdateDeviceList';

function  yapiGetAllDevices( buffer:pointer;
                             maxsize:integer;
                             var neededsize:integer;
                             errmsg : pansichar):integer; cdecl;
                             external 'yapi.dll' name 'yapiGetAllDevices';

function  apiGetDeviceInfo(d:integer; var infos:yDeviceSt;
                             errmsg : pansichar):integer;  cdecl;
                             external 'yapi.dll' name 'yapiGetDeviceInfo';


var
 errmsgBuffer  : array [0..256] of ansichar;
 dataBuffer    : array [0..127] of integer;   // max of 128 USB devices
 errmsg,data   : pansichar;
 neededsize,i  : integer;
 devinfos      : yDeviceSt;

begin
  errmsg  :=  @errmsgBuffer;

  // API  initialization
  if(yapiInitAPI(1,errmsg)<0) then
   begin
    writeln(errmsg);
    halt;
  end;

   // forces a device inventory
  if( yapiUpdateDeviceList(1,errmsg)<0) then
    begin
     writeln(errmsg);
     halt;
   end;

  // loads all device handles into dataBuffer
  if yapiGetAllDevices(@dataBuffer,sizeof(dataBuffer),neededsize,errmsg)<0 then
    begin
     writeln(errmsg);
     halt;
    end;

  // gets device info from each handle
  for i:=0 to  neededsize div sizeof(integer)-1 do
   begin
     if (apiGetDeviceInfo(dataBuffer[i], devinfos, errmsg)<0) then
       begin
         writeln(errmsg);
         halt;
       end;
     writeln(pansichar(@devinfos.serial)+' ('+pansichar(@devinfos.productname)+')');
   end;

end.

19.4. Porting the high level library

As all the sources of the Yoctopuce API are fully provided, you can very well port the whole API in the language of your choice. Note, however, that a large portion of the API source code is automatically generated.

Therefore, it is not necessary for you to port the complete API. You only need to port the yocto_api file and one file corresponding to a function, for example yocto_relay. After a little additional work, Yoctopuce is then able to generate all other files. Therefore, we highly recommend that you contact Yoctopuce support before undertaking to port the Yoctopuce library in another language. Collaborative work is advantageous to both parties.

20. High-level API Reference

This chapter summarizes the high-level API functions to drive your Yocto-MaxiRelay. Syntax and exact type names may vary from one language to another, but, unless otherwise stated, all the functions are available in every language. For detailed information regarding the types of arguments and return values for a given language, refer to the definition file for this language (yocto_api.* as well as the other yocto_* files that define the function interfaces).

For languages which support exceptions, all of these functions throw exceptions in case of error by default, rather than returning the documented error value for each function. This is by design, to facilitate debugging. It is however possible to disable the use of exceptions using the yDisableExceptions() function, in case you prefer to work with functions that return error values.

This chapter does not repeat the programming concepts described earlier, in order to stay as concise as possible. In case of doubt, do not hesitate to go back to the chapter describing in details all configurable attributes.

20.1. General functions

These general functions should be used to initialize and configure the Yoctopuce library. In most cases, a simple call to function yRegisterHub() should be enough. The module-specific functions yFind...() or yFirst...() should then be used to retrieve an object that provides interaction with the module.

In order to use the functions described here, you should include:

js
<script type='text/javascript' src='yocto_api.js'></script>
nodejs
var yoctolib = require('yoctolib');
var YAPI = yoctolib.YAPI;
var YModule = yoctolib.YModule;
php
require_once('yocto_api.php');
cpp
#include "yocto_api.h"
m
#import "yocto_api.h"
pas
uses yocto_api;
vb
yocto_api.vb
cs
yocto_api.cs
java
import com.yoctopuce.YoctoAPI.YModule;
py
from yocto_api import *
Global functions
yCheckLogicalName(name)

Checks if a given string is valid as logical name for a module or a function.

yDisableExceptions()

Disables the use of exceptions to report runtime errors.

yEnableExceptions()

Re-enables the use of exceptions for runtime error handling.

yEnableUSBHost(osContext)

This function is used only on Android.

yFreeAPI()

Frees dynamically allocated memory blocks used by the Yoctopuce library.

yGetAPIVersion()

Returns the version identifier for the Yoctopuce library in use.

yGetTickCount()

Returns the current value of a monotone millisecond-based time counter.

yHandleEvents(errmsg)

Maintains the device-to-library communication channel.

yInitAPI(mode, errmsg)

Initializes the Yoctopuce programming library explicitly.

yPreregisterHub(url, errmsg)

Fault-tolerant alternative to RegisterHub().

yRegisterDeviceArrivalCallback(arrivalCallback)

Register a callback function, to be called each time a device is pluged.

yRegisterDeviceRemovalCallback(removalCallback)

Register a callback function, to be called each time a device is unpluged.

yRegisterHub(url, errmsg)

Setup the Yoctopuce library to use modules connected on a given machine.

yRegisterHubDiscoveryCallback(callback)

Register a callback function, to be called each time a network hub or a VirtualHub is detected on the local network.

yRegisterLogFunction(logfun)

Registers a log callback function.

ySelectArchitecture(arch)

Select the architecture or the library to be loaded to access to USB.

ySetDelegate(object)

(Objective-C only) Register an object that must follow the procol YDeviceHotPlug.

ySetTimeout(callback, ms_timeout, arguments)

Invoke the specified callback function after a given timeout.

ySleep(ms_duration, errmsg)

Pauses the execution flow for a specified duration.

yUnregisterHub(url)

Setup the Yoctopuce library to no more use modules connected on a previously registered machine with RegisterHub.

yUpdateDeviceList(errmsg)

Triggers a (re)detection of connected Yoctopuce modules.

yUpdateDeviceList_async(callback, context)

Triggers a (re)detection of connected Yoctopuce modules.

YAPI.CheckLogicalName()
yCheckLogicalName()
yCheckLogicalName()YAPI.CheckLogicalName()yCheckLogicalName()yCheckLogicalName()yCheckLogicalName()yCheckLogicalName()yCheckLogicalName()YAPI.CheckLogicalName()YAPI.CheckLogicalName()YAPI.CheckLogicalName()

Checks if a given string is valid as logical name for a module or a function.

js
function yCheckLogicalName(name)
nodejs
function CheckLogicalName(name)
php
function yCheckLogicalName($name)
cpp
bool yCheckLogicalName(const string& name)
m
BOOL yCheckLogicalName(NSString * name)
pas
function yCheckLogicalName(name: string): boolean
vb
function yCheckLogicalName(ByVal name As String) As Boolean
cs
bool CheckLogicalName(string name)
java
boolean CheckLogicalName(String name)
py
def CheckLogicalName(name)

A valid logical name has a maximum of 19 characters, all among A..Z, a..z, 0..9, _, and -. If you try to configure a logical name with an incorrect string, the invalid characters are ignored.

Parameters :

namea string containing the name to check.

Returns :

true if the name is valid, false otherwise.

YAPI.DisableExceptions()
yDisableExceptions()
yDisableExceptions()YAPI.DisableExceptions()yDisableExceptions()yDisableExceptions()yDisableExceptions()yDisableExceptions()yDisableExceptions()YAPI.DisableExceptions()YAPI.DisableExceptions()

Disables the use of exceptions to report runtime errors.

js
function yDisableExceptions()
nodejs
function DisableExceptions()
php
function yDisableExceptions()
cpp
void yDisableExceptions()
m
void yDisableExceptions()
pas
procedure yDisableExceptions()
vb
procedure yDisableExceptions()
cs
void DisableExceptions()
py
def DisableExceptions()

When exceptions are disabled, every function returns a specific error value which depends on its type and which is documented in this reference manual.

YAPI.EnableExceptions()
yEnableExceptions()
yEnableExceptions()YAPI.EnableExceptions()yEnableExceptions()yEnableExceptions()yEnableExceptions()yEnableExceptions()yEnableExceptions()YAPI.EnableExceptions()YAPI.EnableExceptions()

Re-enables the use of exceptions for runtime error handling.

js
function yEnableExceptions()
nodejs
function EnableExceptions()
php
function yEnableExceptions()
cpp
void yEnableExceptions()
m
void yEnableExceptions()
pas
procedure yEnableExceptions()
vb
procedure yEnableExceptions()
cs
void EnableExceptions()
py
def EnableExceptions()

Be aware than when exceptions are enabled, every function that fails triggers an exception. If the exception is not caught by the user code, it either fires the debugger or aborts (i.e. crash) the program. On failure, throws an exception or returns a negative error code.

YAPI.EnableUSBHost()
yEnableUSBHost()
YAPI.EnableUSBHost()

This function is used only on Android.

java
synchronized static void EnableUSBHost(Object osContext)

Before calling yRegisterHub("usb") you need to activate the USB host port of the system. This function takes as argument, an object of class android.content.Context (or any subclasee). It is not necessary to call this function to reach modules through the network.

Parameters :

On failure, throws an exception.
osContextan object of class android.content.Context (or any subclass).

YAPI.FreeAPI()
yFreeAPI()
yFreeAPI()YAPI.FreeAPI()yFreeAPI()yFreeAPI()yFreeAPI()yFreeAPI()yFreeAPI()YAPI.FreeAPI()YAPI.FreeAPI()YAPI.FreeAPI()

Frees dynamically allocated memory blocks used by the Yoctopuce library.

js
function yFreeAPI()
nodejs
function FreeAPI()
php
function yFreeAPI()
cpp
void yFreeAPI()
m
void yFreeAPI()
pas
procedure yFreeAPI()
vb
procedure yFreeAPI()
cs
void FreeAPI()
java
synchronized static void FreeAPI()
py
def FreeAPI()

It is generally not required to call this function, unless you want to free all dynamically allocated memory blocks in order to track a memory leak for instance. You should not call any other library function after calling yFreeAPI(), or your program will crash.

YAPI.GetAPIVersion()
yGetAPIVersion()
yGetAPIVersion()YAPI.GetAPIVersion()yGetAPIVersion()yGetAPIVersion()yGetAPIVersion()yGetAPIVersion()yGetAPIVersion()YAPI.GetAPIVersion()YAPI.GetAPIVersion()YAPI.GetAPIVersion()

Returns the version identifier for the Yoctopuce library in use.

js
function yGetAPIVersion()
nodejs
function GetAPIVersion()
php
function yGetAPIVersion()
cpp
string yGetAPIVersion()
m
NSString* yGetAPIVersion()
pas
function yGetAPIVersion(): string
vb
function yGetAPIVersion() As String
cs
String GetAPIVersion()
java
String GetAPIVersion()
py
def GetAPIVersion()

The version is a string in the form "Major.Minor.Build", for instance "1.01.5535". For languages using an external DLL (for instance C#, VisualBasic or Delphi), the character string includes as well the DLL version, for instance "1.01.5535 (1.01.5439)".

If you want to verify in your code that the library version is compatible with the version that you have used during development, verify that the major number is strictly equal and that the minor number is greater or equal. The build number is not relevant with respect to the library compatibility.

Returns :

a character string describing the library version.

YAPI.GetTickCount()
yGetTickCount()
yGetTickCount()YAPI.GetTickCount()yGetTickCount()yGetTickCount()yGetTickCount()yGetTickCount()yGetTickCount()YAPI.GetTickCount()YAPI.GetTickCount()YAPI.GetTickCount()

Returns the current value of a monotone millisecond-based time counter.

js
function yGetTickCount()
nodejs
function GetTickCount()
php
function yGetTickCount()
cpp
u64 yGetTickCount()
m
u64 yGetTickCount()
pas
function yGetTickCount(): u64
vb
function yGetTickCount() As Long
cs
ulong GetTickCount()
java
long GetTickCount()
py
def GetTickCount()

This counter can be used to compute delays in relation with Yoctopuce devices, which also uses the millisecond as timebase.

Returns :

a long integer corresponding to the millisecond counter.

YAPI.HandleEvents()
yHandleEvents()
yHandleEvents()YAPI.HandleEvents()yHandleEvents()yHandleEvents()yHandleEvents()yHandleEvents()yHandleEvents()YAPI.HandleEvents()YAPI.HandleEvents()YAPI.HandleEvents()

Maintains the device-to-library communication channel.

js
function yHandleEvents(errmsg)
nodejs
function HandleEvents(errmsg)
php
function yHandleEvents(&$errmsg)
cpp
YRETCODE yHandleEvents(string& errmsg)
m
YRETCODE yHandleEvents(NSError** errmsg)
pas
function yHandleEvents(var errmsg: string): integer
vb
function yHandleEvents(ByRef errmsg As String) As YRETCODE
cs
YRETCODE HandleEvents(ref string errmsg)
java
int HandleEvents()
py
def HandleEvents(errmsg=None)

If your program includes significant loops, you may want to include a call to this function to make sure that the library takes care of the information pushed by the modules on the communication channels. This is not strictly necessary, but it may improve the reactivity of the library for the following commands.

This function may signal an error in case there is a communication problem while contacting a module.

Parameters :

errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

YAPI.InitAPI()
yInitAPI()
yInitAPI()YAPI.InitAPI()yInitAPI()yInitAPI()yInitAPI()yInitAPI()yInitAPI()YAPI.InitAPI()YAPI.InitAPI()YAPI.InitAPI()

Initializes the Yoctopuce programming library explicitly.

js
function yInitAPI(mode, errmsg)
nodejs
function InitAPI(mode, errmsg)
php
function yInitAPI($mode, &$errmsg)
cpp
YRETCODE yInitAPI(int mode, string& errmsg)
m
YRETCODE yInitAPI(int mode, NSError** errmsg)
pas
function yInitAPI(mode: integer, var errmsg: string): integer
vb
function yInitAPI(ByVal mode As Integer, ByRef errmsg As String) As Integer
cs
int InitAPI(int mode, ref string errmsg)
java
synchronized static int InitAPI(int mode)
py
def InitAPI(mode, errmsg=None)

It is not strictly needed to call yInitAPI(), as the library is automatically initialized when calling yRegisterHub() for the first time.

When Y_DETECT_NONE is used as detection mode, you must explicitly use yRegisterHub() to point the API to the VirtualHub on which your devices are connected before trying to access them.

Parameters :

modean integer corresponding to the type of automatic device detection to use. Possible values are Y_DETECT_NONE, Y_DETECT_USB, Y_DETECT_NET, and Y_DETECT_ALL.
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

YAPI.PreregisterHub()
yPreregisterHub()
yPreregisterHub()YAPI.PreregisterHub()yPreregisterHub()yPreregisterHub()yPreregisterHub()yPreregisterHub()yPreregisterHub()YAPI.PreregisterHub()YAPI.PreregisterHub()YAPI.PreregisterHub()

Fault-tolerant alternative to RegisterHub().

js
function yPreregisterHub(url, errmsg)
nodejs
function PreregisterHub(url, errmsg)
php
function yPreregisterHub($url, &$errmsg)
cpp
YRETCODE yPreregisterHub(const string& url, string& errmsg)
m
YRETCODE yPreregisterHub(NSString * url, NSError** errmsg)
pas
function yPreregisterHub(url: string, var errmsg: string): integer
vb
function yPreregisterHub(ByVal url As String,
  ByRef errmsg As String) As Integer
cs
int PreregisterHub(string url, ref string errmsg)
java
synchronized static int PreregisterHub(String url)
py
def PreregisterHub(url, errmsg=None)

This function has the same purpose and same arguments as RegisterHub(), but does not trigger an error when the selected hub is not available at the time of the function call. This makes it possible to register a network hub independently of the current connectivity, and to try to contact it only when a device is actively needed.

Parameters :

urla string containing either "usb","callback" or the root URL of the hub to monitor
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.RegisterDeviceArrivalCallback()
yRegisterDeviceArrivalCallback()
yRegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()yRegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()YAPI.RegisterDeviceArrivalCallback()

Register a callback function, to be called each time a device is pluged.

js
function yRegisterDeviceArrivalCallback(arrivalCallback)
nodejs
function RegisterDeviceArrivalCallback(arrivalCallback)
php
function yRegisterDeviceArrivalCallback($arrivalCallback)
cpp
void yRegisterDeviceArrivalCallback(yDeviceUpdateCallback arrivalCallback)
m
void yRegisterDeviceArrivalCallback(yDeviceUpdateCallback arrivalCallback)
pas
procedure yRegisterDeviceArrivalCallback(arrivalCallback: yDeviceUpdateFunc)
vb
procedure yRegisterDeviceArrivalCallback(ByVal arrivalCallback As yDeviceUpdateFunc)
cs
void RegisterDeviceArrivalCallback(yDeviceUpdateFunc arrivalCallback)
java
synchronized static void RegisterDeviceArrivalCallback(DeviceArrivalCallback arrivalCallback)
py
def RegisterDeviceArrivalCallback(arrivalCallback)

This callback will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered callback.
arrivalCallbacka procedure taking a YModule parameter, or null

YAPI.RegisterDeviceRemovalCallback()
yRegisterDeviceRemovalCallback()
yRegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()yRegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()YAPI.RegisterDeviceRemovalCallback()

Register a callback function, to be called each time a device is unpluged.

js
function yRegisterDeviceRemovalCallback(removalCallback)
nodejs
function RegisterDeviceRemovalCallback(removalCallback)
php
function yRegisterDeviceRemovalCallback($removalCallback)
cpp
void yRegisterDeviceRemovalCallback(yDeviceUpdateCallback removalCallback)
m
void yRegisterDeviceRemovalCallback(yDeviceUpdateCallback removalCallback)
pas
procedure yRegisterDeviceRemovalCallback(removalCallback: yDeviceUpdateFunc)
vb
procedure yRegisterDeviceRemovalCallback(ByVal removalCallback As yDeviceUpdateFunc)
cs
void RegisterDeviceRemovalCallback(yDeviceUpdateFunc removalCallback)
java
synchronized static void RegisterDeviceRemovalCallback(DeviceRemovalCallback removalCallback)
py
def RegisterDeviceRemovalCallback(removalCallback)

This callback will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered callback.
removalCallbacka procedure taking a YModule parameter, or null

YAPI.RegisterHub()
yRegisterHub()
yRegisterHub()YAPI.RegisterHub()yRegisterHub()yRegisterHub()yRegisterHub()yRegisterHub()yRegisterHub()YAPI.RegisterHub()YAPI.RegisterHub()YAPI.RegisterHub()

Setup the Yoctopuce library to use modules connected on a given machine.

js
function yRegisterHub(url, errmsg)
nodejs
function RegisterHub(url, errmsg)
php
function yRegisterHub($url, &$errmsg)
cpp
YRETCODE yRegisterHub(const string& url, string& errmsg)
m
YRETCODE yRegisterHub(NSString * url, NSError** errmsg)
pas
function yRegisterHub(url: string, var errmsg: string): integer
vb
function yRegisterHub(ByVal url As String,
  ByRef errmsg As String) As Integer
cs
int RegisterHub(string url, ref string errmsg)
java
synchronized static int RegisterHub(String url)
py
def RegisterHub(url, errmsg=None)

The parameter will determine how the API will work. Use the follwing values:

usb: When the usb keyword is used, the API will work with devices connected directly to the USB bus. Some programming languages such a Javascript, PHP, and Java don't provide direct access to USB harware, so usb will not work with these. In this case, use a VirtualHub or a networked YoctoHub (see below).

x.x.x.x or hostname: The API will use the devices connected to the host with the given IP address or hostname. That host can be a regular computer running a VirtualHub, or a networked YoctoHub such as YoctoHub-Ethernet or YoctoHub-Wireless. If you want to use the VirtualHub running on you local computer, use the IP address 127.0.0.1.

callback: that keywork make the API run in "HTTP Callback" mode. This a special mode allowing to take control of Yoctopuce devices through a NAT filter when using a VirtualHub ou a networked YoctoHub. You only need to configure your hub to call your server script on a regular basis. This mode is currently available for PHP and Node.JS only.

Be aware that only one application can use direct USB access at a given time on a machine. Multiple access would cause conflicts while trying to access the USB modules. In particular, this means that you must stop the VirtualHub software before starting an application that uses direct USB access. The workaround for this limitation is to setup the library to use the VirtualHub rather than direct USB access.

If acces control has been activated on the hub, virtual or not, you want to reach, the URL parameter should look like:

http://username:password@adresse:port

You can call RegisterHub several times to connect to several machines.

Parameters :

urla string containing either "usb","callback" or the root URL of the hub to monitor
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds.

On failure, throws an exception or returns a negative error code.

YAPI.RegisterHubDiscoveryCallback()
yRegisterHubDiscoveryCallback()
YAPI.RegisterHubDiscoveryCallback()

Register a callback function, to be called each time a network hub or a VirtualHub is detected on the local network.

java
void RegisterHubDiscoveryCallback(NewHubCallback callback)

Parameters :

to unregister a previously registered callback.
callbacka procedure taking a two string as parameter, or null

YAPI.RegisterLogFunction()
yRegisterLogFunction()
yRegisterLogFunction()yRegisterLogFunction()yRegisterLogFunction()yRegisterLogFunction()YAPI.RegisterLogFunction()YAPI.RegisterLogFunction()YAPI.RegisterLogFunction()

Registers a log callback function.

cpp
void yRegisterLogFunction(yLogFunction logfun)
m
void yRegisterLogFunction(yLogCallback logfun)
pas
procedure yRegisterLogFunction(logfun: yLogFunc)
vb
procedure yRegisterLogFunction(ByVal logfun As yLogFunc)
cs
void RegisterLogFunction(yLogFunc logfun)
java
void RegisterLogFunction(LogCallback logfun)
py
def RegisterLogFunction(logfun)

This callback will be called each time the API have something to say. Quite usefull to debug the API.

Parameters :

to unregister a previously registered callback.
logfuna procedure taking a string parameter, or null

YAPI.SelectArchitecture()
ySelectArchitecture()
YAPI.SelectArchitecture()

Select the architecture or the library to be loaded to access to USB.

py
def SelectArchitecture(arch)

By default, the Python library automatically detects the appropriate library to use. However, for Linux ARM, it not possible to reliably distinguish between a Hard Float (armhf) and a Soft Float (armel) install. For in this case, it is therefore recommended to manually select the proper architecture by calling SelectArchitecture() before any other call to the library.

Parameters :

archA string containing the architecture to use. Possibles value are: "armhf","armel", "i386","x86_64","32bit", "64bit"

Returns :

nothing.

On failure, throws an exception.

YAPI.SetDelegate()
ySetDelegate()
ySetDelegate()

(Objective-C only) Register an object that must follow the procol YDeviceHotPlug.

m
void ySetDelegate(id object)

The methodes yDeviceArrival and yDeviceRemoval will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.

Parameters :

to unregister a previously registered object.
objectan object that must follow the procol YAPIDelegate, or nil

YAPI.SetTimeout()
ySetTimeout()
ySetTimeout()YAPI.SetTimeout()

Invoke the specified callback function after a given timeout.

js
function ySetTimeout(callback, ms_timeout, arguments)
nodejs
function SetTimeout(callback, ms_timeout, arguments)

This function behaves more or less like Javascript setTimeout, but during the waiting time, it will call yHandleEvents and yUpdateDeviceList periodically, in order to keep the API up-to-date with current devices.

Parameters :

callbackthe function to call after the timeout occurs. On Microsoft Internet Explorer, the callback must be provided as a string to be evaluated.
ms_timeoutan integer corresponding to the duration of the timeout, in milliseconds.
argumentsadditional arguments to be passed to the callback function can be provided, if needed (not supported on Microsoft Internet Explorer).

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

YAPI.Sleep()
ySleep()
ySleep()YAPI.Sleep()ySleep()ySleep()ySleep()ySleep()ySleep()YAPI.Sleep()YAPI.Sleep()YAPI.Sleep()

Pauses the execution flow for a specified duration.

js
function ySleep(ms_duration, errmsg)
nodejs
function Sleep(ms_duration, errmsg)
php
function ySleep($ms_duration, &$errmsg)
cpp
YRETCODE ySleep(unsigned ms_duration, string& errmsg)
m
YRETCODE ySleep(unsigned ms_duration, NSError ** errmsg)
pas
function ySleep(ms_duration: integer, var errmsg: string): integer
vb
function ySleep(ByVal ms_duration As Integer,
  ByRef errmsg As String) As Integer
cs
int Sleep(int ms_duration, ref string errmsg)
java
int Sleep(long ms_duration)
py
def Sleep(ms_duration, errmsg=None)

This function implements a passive waiting loop, meaning that it does not consume CPU cycles significatively. The processor is left available for other threads and processes. During the pause, the library nevertheless reads from time to time information from the Yoctopuce modules by calling yHandleEvents(), in order to stay up-to-date.

This function may signal an error in case there is a communication problem while contacting a module.

Parameters :

ms_durationan integer corresponding to the duration of the pause, in milliseconds.
errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

YAPI.UnregisterHub()
yUnregisterHub()
yUnregisterHub()YAPI.UnregisterHub()yUnregisterHub()yUnregisterHub()yUnregisterHub()yUnregisterHub()yUnregisterHub()YAPI.UnregisterHub()YAPI.UnregisterHub()YAPI.UnregisterHub()

Setup the Yoctopuce library to no more use modules connected on a previously registered machine with RegisterHub.

js
function yUnregisterHub(url)
nodejs
function UnregisterHub(url)
php
function yUnregisterHub($url)
cpp
void yUnregisterHub(const string& url)
m
void yUnregisterHub(NSString * url)
pas
procedure yUnregisterHub(url: string)
vb
procedure yUnregisterHub(ByVal url As String)
cs
void UnregisterHub(string url)
java
synchronized static void UnregisterHub(String url)
py
def UnregisterHub(url)

Parameters :

root URL of the hub to monitor
urla string containing either "usb" or the

YAPI.UpdateDeviceList()
yUpdateDeviceList()
yUpdateDeviceList()YAPI.UpdateDeviceList()yUpdateDeviceList()yUpdateDeviceList()yUpdateDeviceList()yUpdateDeviceList()yUpdateDeviceList()YAPI.UpdateDeviceList()YAPI.UpdateDeviceList()YAPI.UpdateDeviceList()

Triggers a (re)detection of connected Yoctopuce modules.

js
function yUpdateDeviceList(errmsg)
nodejs
function UpdateDeviceList(errmsg)
php
function yUpdateDeviceList(&$errmsg)
cpp
YRETCODE yUpdateDeviceList(string& errmsg)
m
YRETCODE yUpdateDeviceList(NSError** errmsg)
pas
function yUpdateDeviceList(var errmsg: string): integer
vb
function yUpdateDeviceList(ByRef errmsg As String) As YRETCODE
cs
YRETCODE UpdateDeviceList(ref string errmsg)
java
int UpdateDeviceList()
py
def UpdateDeviceList(errmsg=None)

The library searches the machines or USB ports previously registered using yRegisterHub(), and invokes any user-defined callback function in case a change in the list of connected devices is detected.

This function can be called as frequently as desired to refresh the device list and to make the application aware of hot-plug events.

Parameters :

errmsga string passed by reference to receive any error message.

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

YAPI.UpdateDeviceList_async()
yUpdateDeviceList_async()
yUpdateDeviceList_async()YAPI.UpdateDeviceList_async()

Triggers a (re)detection of connected Yoctopuce modules.

js
function yUpdateDeviceList_async(callback, context)
nodejs
function UpdateDeviceList_async(callback, context)

The library searches the machines or USB ports previously registered using yRegisterHub(), and invokes any user-defined callback function in case a change in the list of connected devices is detected.

This function can be called as frequently as desired to refresh the device list and to make the application aware of hot-plug events.

This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox Javascript VM that does not implement context switching during blocking I/O calls.

Parameters :

callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the result code (YAPI_SUCCESS if the operation completes successfully) and the error message.
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

20.2. Module control interface

This interface is identical for all Yoctopuce USB modules. It can be used to control the module global parameters, and to enumerate the functions provided by each module.

In order to use the functions described here, you should include:

js
<script type='text/javascript' src='yocto_api.js'></script>
nodejs
var yoctolib = require('yoctolib');
var YAPI = yoctolib.YAPI;
var YModule = yoctolib.YModule;
php
require_once('yocto_api.php');
cpp
#include "yocto_api.h"
m
#import "yocto_api.h"
pas
uses yocto_api;
vb
yocto_api.vb
cs
yocto_api.cs
java
import com.yoctopuce.YoctoAPI.YModule;
py
from yocto_api import *
Global functions
yFindModule(func)

Allows you to find a module from its serial number or from its logical name.

yFirstModule()

Starts the enumeration of modules currently accessible.

YModule methods
module→describe()

Returns a descriptive text that identifies the module.

module→download(pathname)

Downloads the specified built-in file and returns a binary buffer with its content.

module→functionCount()

Returns the number of functions (beside the "module" interface) available on the module.

module→functionId(functionIndex)

Retrieves the hardware identifier of the nth function on the module.

module→functionName(functionIndex)

Retrieves the logical name of the nth function on the module.

module→functionValue(functionIndex)

Retrieves the advertised value of the nth function on the module.

module→get_beacon()

Returns the state of the localization beacon.

module→get_errorMessage()

Returns the error message of the latest error with this module object.

module→get_errorType()

Returns the numerical error code of the latest error with this module object.

module→get_firmwareRelease()

Returns the version of the firmware embedded in the module.

module→get_hardwareId()

Returns the unique hardware identifier of the module.

module→get_icon2d()

Returns the icon of the module.

module→get_lastLogs()

Returns a string with last logs of the module.

module→get_logicalName()

Returns the logical name of the module.

module→get_luminosity()

Returns the luminosity of the module informative leds (from 0 to 100).

module→get_persistentSettings()

Returns the current state of persistent module settings.

module→get_productId()

Returns the USB device identifier of the module.

module→get_productName()

Returns the commercial name of the module, as set by the factory.

module→get_productRelease()

Returns the hardware release version of the module.

module→get_rebootCountdown()

Returns the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled.

module→get_serialNumber()

Returns the serial number of the module, as set by the factory.

module→get_upTime()

Returns the number of milliseconds spent since the module was powered on.

module→get_usbBandwidth()

Returns the number of USB interfaces used by the module.

module→get_usbCurrent()

Returns the current consumed by the module on the USB bus, in milli-amps.

module→get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

module→isOnline()

Checks if the module is currently reachable, without raising any error.

module→isOnline_async(callback, context)

Checks if the module is currently reachable, without raising any error.

module→load(msValidity)

Preloads the module cache with a specified validity duration.

module→load_async(msValidity, callback, context)

Preloads the module cache with a specified validity duration (asynchronous version).

module→nextModule()

Continues the module enumeration started using yFirstModule().

module→reboot(secBeforeReboot)

Schedules a simple module reboot after the given number of seconds.

module→revertFromFlash()

Reloads the settings stored in the nonvolatile memory, as when the module is powered on.

module→saveToFlash()

Saves current settings in the nonvolatile memory of the module.

module→set_beacon(newval)

Turns on or off the module localization beacon.

module→set_logicalName(newval)

Changes the logical name of the module.

module→set_luminosity(newval)

Changes the luminosity of the module informative leds.

module→set_usbBandwidth(newval)

Changes the number of USB interfaces used by the module.

module→set_userData(data)

Stores a user context provided as argument in the userData attribute of the function.

module→triggerFirmwareUpdate(secBeforeReboot)

Schedules a module reboot into special firmware update mode.

module→wait_async(callback, context)

Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.

YModule.FindModule()
yFindModule()
yFindModule()YModule.FindModule()yFindModule()yFindModule()yFindModule()yFindModule()yFindModule()YModule.FindModule()YModule.FindModule()YModule.FindModule()

Allows you to find a module from its serial number or from its logical name.

js
function yFindModule(func)
nodejs
function FindModule(func)
php
function yFindModule($func)
cpp
YModule* yFindModule(string func)
m
+(YModule*) yFindModule: (NSString*) func
pas
function yFindModule(func: string): TYModule
vb
function yFindModule(ByVal func As String) As YModule
cs
YModule FindModule(string func)
java
YModule FindModule(String func)
py
def FindModule(func)

This function does not require that the module is online at the time it is invoked. The returned object is nevertheless valid. Use the method YModule.isOnline() to test if the module is indeed online at a given time. In case of ambiguity when looking for a module by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.

Parameters :

funca string containing either the serial number or the logical name of the desired module

Returns :

a YModule object allowing you to drive the module or get additional information on the module.

YModule.FirstModule()
yFirstModule()
yFirstModule()YModule.FirstModule()yFirstModule()yFirstModule()yFirstModule()yFirstModule()yFirstModule()YModule.FirstModule()YModule.FirstModule()YModule.FirstModule()

Starts the enumeration of modules currently accessible.

js
function yFirstModule()
nodejs
function FirstModule()
php
function yFirstModule()
cpp
YModule* yFirstModule()
m
YModule* yFirstModule()
pas
function yFirstModule(): TYModule
vb
function yFirstModule() As YModule
cs
YModule FirstModule()
java
YModule FirstModule()
py
def FirstModule()

Use the method YModule.nextModule() to iterate on the next modules.

Returns :

a pointer to a YModule object, corresponding to the first module currently online, or a null pointer if there are none.

module→describe()module.describe()module.describe()module→describe()module→describe()[module describe]module.describe()module.describe()module.describe()module.describe()module.describe()

Returns a descriptive text that identifies the module.

js
function describe()
nodejs
function describe()
php
function describe()
cpp
string describe()
m
-(NSString*) describe
pas
function describe(): string
vb
function describe() As String
cs
string describe()
java
String describe()
py
def describe()

The text may include either the logical name or the serial number of the module.

Returns :

a string that describes the module

module→download()module.download()module.download()module→download()module→download()[module download: ]module.download()module.download()module.download()YModule download

Downloads the specified built-in file and returns a binary buffer with its content.

js
function download(pathname)
nodejs
function download(pathname)
php
function download($pathname)
cpp
string download(string pathname)
m
-(NSData*) download: (NSString*) pathname
pas
function download(pathname: string): TByteArray
vb
function download() As Byte
py
def download(pathname)
cmd
YModule target download pathname

Parameters :

pathnamename of the new file to load

Returns :

a binary buffer with the file content

On failure, throws an exception or returns an empty content.

module→functionCount()module.functionCount()module.functionCount()module→functionCount()module→functionCount()[module functionCount]module.functionCount()module.functionCount()module.functionCount()module.functionCount()

Returns the number of functions (beside the "module" interface) available on the module.

js
function functionCount()
nodejs
function functionCount()
php
function functionCount()
cpp
int functionCount()
m
-(int) functionCount
pas
function functionCount(): integer
vb
function functionCount() As Integer
cs
int functionCount()
py
def functionCount()

Returns :

the number of functions on the module

On failure, throws an exception or returns a negative error code.

module→functionId()module.functionId()module.functionId()module→functionId()module→functionId()[module functionId: ]module.functionId()module.functionId()module.functionId()module.functionId()

Retrieves the hardware identifier of the nth function on the module.

js
function functionId(functionIndex)
nodejs
function functionId(functionIndex)
php
function functionId($functionIndex)
cpp
string functionId(int functionIndex)
m
-(NSString*) functionId: (int) functionIndex
pas
function functionId(functionIndex: integer): string
vb
function functionId(ByVal functionIndex As Integer) As String
cs
string functionId(int functionIndex)
py
def functionId(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a string corresponding to the unambiguous hardware identifier of the requested module function

On failure, throws an exception or returns an empty string.

module→functionName()module.functionName()module.functionName()module→functionName()module→functionName()[module functionName: ]module.functionName()module.functionName()module.functionName()module.functionName()

Retrieves the logical name of the nth function on the module.

js
function functionName(functionIndex)
nodejs
function functionName(functionIndex)
php
function functionName($functionIndex)
cpp
string functionName(int functionIndex)
m
-(NSString*) functionName: (int) functionIndex
pas
function functionName(functionIndex: integer): string
vb
function functionName(ByVal functionIndex As Integer) As String
cs
string functionName(int functionIndex)
py
def functionName(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a string corresponding to the logical name of the requested module function

On failure, throws an exception or returns an empty string.

module→functionValue()module.functionValue()module.functionValue()module→functionValue()module→functionValue()[module functionValue: ]module.functionValue()module.functionValue()module.functionValue()module.functionValue()

Retrieves the advertised value of the nth function on the module.

js
function functionValue(functionIndex)
nodejs
function functionValue(functionIndex)
php
function functionValue($functionIndex)
cpp
string functionValue(int functionIndex)
m
-(NSString*) functionValue: (int) functionIndex
pas
function functionValue(functionIndex: integer): string
vb
function functionValue(ByVal functionIndex As Integer) As String
cs
string functionValue(int functionIndex)
py
def functionValue(functionIndex)

Parameters :

functionIndexthe index of the function for which the information is desired, starting at 0 for the first function.

Returns :

a short string (up to 6 characters) corresponding to the advertised value of the requested module function

On failure, throws an exception or returns an empty string.

module→get_beacon()
module→beacon()
module.get_beacon()module.get_beacon()module→get_beacon()module→get_beacon()[module beacon]module.get_beacon()module.get_beacon()module.get_beacon()module.get_beacon()module.get_beacon()YModule get_beacon

Returns the state of the localization beacon.

js
function get_beacon()
nodejs
function get_beacon()
php
function get_beacon()
cpp
Y_BEACON_enum get_beacon()
m
-(Y_BEACON_enum) beacon
pas
function get_beacon(): Integer
vb
function get_beacon() As Integer
cs
int get_beacon()
java
int get_beacon()
py
def get_beacon()
cmd
YModule target get_beacon

Returns :

either Y_BEACON_OFF or Y_BEACON_ON, according to the state of the localization beacon

On failure, throws an exception or returns Y_BEACON_INVALID.

module→get_errorMessage()
module→errorMessage()
module.get_errorMessage()module.get_errorMessage()module→get_errorMessage()module→get_errorMessage()[module errorMessage]module.get_errorMessage()module.get_errorMessage()module.get_errorMessage()module.get_errorMessage()module.get_errorMessage()

Returns the error message of the latest error with this module object.

js
function get_errorMessage()
nodejs
function get_errorMessage()
php
function get_errorMessage()
cpp
string get_errorMessage()
m
-(NSString*) errorMessage
pas
function get_errorMessage(): string
vb
function get_errorMessage() As String
cs
string get_errorMessage()
java
String get_errorMessage()
py
def get_errorMessage()

This method is mostly useful when using the Yoctopuce library with exceptions disabled.

Returns :

a string corresponding to the latest error message that occured while using this module object

module→get_errorType()
module→errorType()
module.get_errorType()module.get_errorType()module→get_errorType()module→get_errorType()module.get_errorType()module.get_errorType()module.get_errorType()module.get_errorType()module.get_errorType()

Returns the numerical error code of the latest error with this module object.

js
function get_errorType()
nodejs
function get_errorType()
php
function get_errorType()
cpp
YRETCODE get_errorType()
pas
function get_errorType(): YRETCODE
vb
function get_errorType() As YRETCODE
cs
YRETCODE get_errorType()
java
int get_errorType()
py
def get_errorType()

This method is mostly useful when using the Yoctopuce library with exceptions disabled.

Returns :

a number corresponding to the code of the latest error that occured while using this module object

module→get_firmwareRelease()
module→firmwareRelease()
module.get_firmwareRelease()module.get_firmwareRelease()module→get_firmwareRelease()module→get_firmwareRelease()[module firmwareRelease]module.get_firmwareRelease()module.get_firmwareRelease()module.get_firmwareRelease()module.get_firmwareRelease()module.get_firmwareRelease()YModule get_firmwareRelease

Returns the version of the firmware embedded in the module.

js
function get_firmwareRelease()
nodejs
function get_firmwareRelease()
php
function get_firmwareRelease()
cpp
string get_firmwareRelease()
m
-(NSString*) firmwareRelease
pas
function get_firmwareRelease(): string
vb
function get_firmwareRelease() As String
cs
string get_firmwareRelease()
java
String get_firmwareRelease()
py
def get_firmwareRelease()
cmd
YModule target get_firmwareRelease

Returns :

a string corresponding to the version of the firmware embedded in the module

On failure, throws an exception or returns Y_FIRMWARERELEASE_INVALID.

module→get_hardwareId()
module→hardwareId()
module.get_hardwareId()module.get_hardwareId()module→get_hardwareId()module→get_hardwareId()[module hardwareId]module.get_hardwareId()module.get_hardwareId()module.get_hardwareId()module.get_hardwareId()

Returns the unique hardware identifier of the module.

js
function get_hardwareId()
nodejs
function get_hardwareId()
php
function get_hardwareId()
cpp
string get_hardwareId()
m
-(NSString*) hardwareId
vb
function get_hardwareId() As String
cs
string get_hardwareId()
java
String get_hardwareId()
py
def get_hardwareId()

The unique hardware identifier is made of the device serial number followed by string ".module".

Returns :

a string that uniquely identifies the module

module→get_icon2d()
module→icon2d()
module.get_icon2d()module.get_icon2d()module→get_icon2d()module→get_icon2d()[module icon2d]module.get_icon2d()module.get_icon2d()module.get_icon2d()YModule get_icon2d

Returns the icon of the module.

js
function get_icon2d()
nodejs
function get_icon2d()
php
function get_icon2d()
cpp
string get_icon2d()
m
-(NSData*) icon2d
pas
function get_icon2d(): TByteArray
vb
function get_icon2d() As Byte
py
def get_icon2d()
cmd
YModule target get_icon2d

The icon is a PNG image and does not exceeds 1536 bytes.

Returns :

a binary buffer with module icon, in png format.

module→get_lastLogs()
module→lastLogs()
module.get_lastLogs()module.get_lastLogs()module→get_lastLogs()module→get_lastLogs()[module lastLogs]module.get_lastLogs()module.get_lastLogs()module.get_lastLogs()module.get_lastLogs()module.get_lastLogs()YModule get_lastLogs

Returns a string with last logs of the module.

js
function get_lastLogs()
nodejs
function get_lastLogs()
php
function get_lastLogs()
cpp
string get_lastLogs()
m
-(NSString*) lastLogs
pas
function get_lastLogs(): string
vb
function get_lastLogs() As String
cs
string get_lastLogs()
java
String get_lastLogs()
py
def get_lastLogs()
cmd
YModule target get_lastLogs

This method return only logs that are still in the module.

Returns :

a string with last logs of the module.

module→get_logicalName()
module→logicalName()
module.get_logicalName()module.get_logicalName()module→get_logicalName()module→get_logicalName()[module logicalName]module.get_logicalName()module.get_logicalName()module.get_logicalName()module.get_logicalName()module.get_logicalName()YModule get_logicalName

Returns the logical name of the module.

js
function get_logicalName()
nodejs
function get_logicalName()
php
function get_logicalName()
cpp
string get_logicalName()
m
-(NSString*) logicalName
pas
function get_logicalName(): string
vb
function get_logicalName() As String
cs
string get_logicalName()
java
String get_logicalName()
py
def get_logicalName()
cmd
YModule target get_logicalName

Returns :

a string corresponding to the logical name of the module

On failure, throws an exception or returns Y_LOGICALNAME_INVALID.

module→get_luminosity()
module→luminosity()
module.get_luminosity()module.get_luminosity()module→get_luminosity()module→get_luminosity()[module luminosity]module.get_luminosity()module.get_luminosity()module.get_luminosity()module.get_luminosity()module.get_luminosity()YModule get_luminosity

Returns the luminosity of the module informative leds (from 0 to 100).

js
function get_luminosity()
nodejs
function get_luminosity()
php
function get_luminosity()
cpp
int get_luminosity()
m
-(int) luminosity
pas
function get_luminosity(): LongInt
vb
function get_luminosity() As Integer
cs
int get_luminosity()
java
int get_luminosity()
py
def get_luminosity()
cmd
YModule target get_luminosity

Returns :

an integer corresponding to the luminosity of the module informative leds (from 0 to 100)

On failure, throws an exception or returns Y_LUMINOSITY_INVALID.

module→get_persistentSettings()
module→persistentSettings()
module.get_persistentSettings()module.get_persistentSettings()module→get_persistentSettings()module→get_persistentSettings()[module persistentSettings]module.get_persistentSettings()module.get_persistentSettings()module.get_persistentSettings()module.get_persistentSettings()module.get_persistentSettings()YModule get_persistentSettings

Returns the current state of persistent module settings.

js
function get_persistentSettings()
nodejs
function get_persistentSettings()
php
function get_persistentSettings()
cpp
Y_PERSISTENTSETTINGS_enum get_persistentSettings()
m
-(Y_PERSISTENTSETTINGS_enum) persistentSettings
pas
function get_persistentSettings(): Integer
vb
function get_persistentSettings() As Integer
cs
int get_persistentSettings()
java
int get_persistentSettings()
py
def get_persistentSettings()
cmd
YModule target get_persistentSettings

Returns :

a value among Y_PERSISTENTSETTINGS_LOADED, Y_PERSISTENTSETTINGS_SAVED and Y_PERSISTENTSETTINGS_MODIFIED corresponding to the current state of persistent module settings

On failure, throws an exception or returns Y_PERSISTENTSETTINGS_INVALID.

module→get_productId()
module→productId()
module.get_productId()module.get_productId()module→get_productId()module→get_productId()[module productId]module.get_productId()module.get_productId()module.get_productId()module.get_productId()module.get_productId()YModule get_productId

Returns the USB device identifier of the module.

js
function get_productId()
nodejs
function get_productId()
php
function get_productId()
cpp
int get_productId()
m
-(int) productId
pas
function get_productId(): LongInt
vb
function get_productId() As Integer
cs
int get_productId()
java
int get_productId()
py
def get_productId()
cmd
YModule target get_productId

Returns :

an integer corresponding to the USB device identifier of the module

On failure, throws an exception or returns Y_PRODUCTID_INVALID.

module→get_productName()
module→productName()
module.get_productName()module.get_productName()module→get_productName()module→get_productName()[module productName]module.get_productName()module.get_productName()module.get_productName()module.get_productName()module.get_productName()YModule get_productName

Returns the commercial name of the module, as set by the factory.

js
function get_productName()
nodejs
function get_productName()
php
function get_productName()
cpp
string get_productName()
m
-(NSString*) productName
pas
function get_productName(): string
vb
function get_productName() As String
cs
string get_productName()
java
String get_productName()
py
def get_productName()
cmd
YModule target get_productName

Returns :

a string corresponding to the commercial name of the module, as set by the factory

On failure, throws an exception or returns Y_PRODUCTNAME_INVALID.

module→get_productRelease()
module→productRelease()
module.get_productRelease()module.get_productRelease()module→get_productRelease()module→get_productRelease()[module productRelease]module.get_productRelease()module.get_productRelease()module.get_productRelease()module.get_productRelease()module.get_productRelease()YModule get_productRelease

Returns the hardware release version of the module.

js
function get_productRelease()
nodejs
function get_productRelease()
php
function get_productRelease()
cpp
int get_productRelease()
m
-(int) productRelease
pas
function get_productRelease(): LongInt
vb
function get_productRelease() As Integer
cs
int get_productRelease()
java
int get_productRelease()
py
def get_productRelease()
cmd
YModule target get_productRelease

Returns :

an integer corresponding to the hardware release version of the module

On failure, throws an exception or returns Y_PRODUCTRELEASE_INVALID.

module→get_rebootCountdown()
module→rebootCountdown()
module.get_rebootCountdown()module.get_rebootCountdown()module→get_rebootCountdown()module→get_rebootCountdown()[module rebootCountdown]module.get_rebootCountdown()module.get_rebootCountdown()module.get_rebootCountdown()module.get_rebootCountdown()module.get_rebootCountdown()YModule get_rebootCountdown

Returns the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled.

js
function get_rebootCountdown()
nodejs
function get_rebootCountdown()
php
function get_rebootCountdown()
cpp
int get_rebootCountdown()
m
-(int) rebootCountdown
pas
function get_rebootCountdown(): LongInt
vb
function get_rebootCountdown() As Integer
cs
int get_rebootCountdown()
java
int get_rebootCountdown()
py
def get_rebootCountdown()
cmd
YModule target get_rebootCountdown

Returns :

an integer corresponding to the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled

On failure, throws an exception or returns Y_REBOOTCOUNTDOWN_INVALID.

module→get_serialNumber()
module→serialNumber()
module.get_serialNumber()module.get_serialNumber()module→get_serialNumber()module→get_serialNumber()[module serialNumber]module.get_serialNumber()module.get_serialNumber()module.get_serialNumber()module.get_serialNumber()module.get_serialNumber()YModule get_serialNumber

Returns the serial number of the module, as set by the factory.

js
function get_serialNumber()
nodejs
function get_serialNumber()
php
function get_serialNumber()
cpp
string get_serialNumber()
m
-(NSString*) serialNumber
pas
function get_serialNumber(): string
vb
function get_serialNumber() As String
cs
string get_serialNumber()
java
String get_serialNumber()
py
def get_serialNumber()
cmd
YModule target get_serialNumber

Returns :

a string corresponding to the serial number of the module, as set by the factory

On failure, throws an exception or returns Y_SERIALNUMBER_INVALID.

module→get_upTime()
module→upTime()
module.get_upTime()module.get_upTime()module→get_upTime()module→get_upTime()[module upTime]module.get_upTime()module.get_upTime()module.get_upTime()module.get_upTime()module.get_upTime()YModule get_upTime

Returns the number of milliseconds spent since the module was powered on.

js
function get_upTime()
nodejs
function get_upTime()
php
function get_upTime()
cpp
s64 get_upTime()
m
-(s64) upTime
pas
function get_upTime(): int64
vb
function get_upTime() As Long
cs
long get_upTime()
java
long get_upTime()
py
def get_upTime()
cmd
YModule target get_upTime

Returns :

an integer corresponding to the number of milliseconds spent since the module was powered on

On failure, throws an exception or returns Y_UPTIME_INVALID.

module→get_usbBandwidth()
module→usbBandwidth()
module.get_usbBandwidth()module.get_usbBandwidth()module→get_usbBandwidth()module→get_usbBandwidth()[module usbBandwidth]module.get_usbBandwidth()module.get_usbBandwidth()module.get_usbBandwidth()module.get_usbBandwidth()module.get_usbBandwidth()YModule get_usbBandwidth

Returns the number of USB interfaces used by the module.

js
function get_usbBandwidth()
nodejs
function get_usbBandwidth()
php
function get_usbBandwidth()
cpp
Y_USBBANDWIDTH_enum get_usbBandwidth()
m
-(Y_USBBANDWIDTH_enum) usbBandwidth
pas
function get_usbBandwidth(): Integer
vb
function get_usbBandwidth() As Integer
cs
int get_usbBandwidth()
java
int get_usbBandwidth()
py
def get_usbBandwidth()
cmd
YModule target get_usbBandwidth

Returns :

either Y_USBBANDWIDTH_SIMPLE or Y_USBBANDWIDTH_DOUBLE, according to the number of USB interfaces used by the module

On failure, throws an exception or returns Y_USBBANDWIDTH_INVALID.

module→get_usbCurrent()
module→usbCurrent()
module.get_usbCurrent()module.get_usbCurrent()module→get_usbCurrent()module→get_usbCurrent()[module usbCurrent]module.get_usbCurrent()module.get_usbCurrent()module.get_usbCurrent()module.get_usbCurrent()module.get_usbCurrent()YModule get_usbCurrent

Returns the current consumed by the module on the USB bus, in milli-amps.

js
function get_usbCurrent()
nodejs
function get_usbCurrent()
php
function get_usbCurrent()
cpp
int get_usbCurrent()
m
-(int) usbCurrent
pas
function get_usbCurrent(): LongInt
vb
function get_usbCurrent() As Integer
cs
int get_usbCurrent()
java
int get_usbCurrent()
py
def get_usbCurrent()
cmd
YModule target get_usbCurrent

Returns :

an integer corresponding to the current consumed by the module on the USB bus, in milli-amps

On failure, throws an exception or returns Y_USBCURRENT_INVALID.

module→get_userData()
module→userData()
module.get_userData()module.get_userData()module→get_userData()module→get_userData()[module userData]module.get_userData()module.get_userData()module.get_userData()module.get_userData()module.get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

js
function get_userData()
nodejs
function get_userData()
php
function get_userData()
cpp
void * get_userData()
m
-(void*) userData
pas
function get_userData(): Tobject
vb
function get_userData() As Object
cs
object get_userData()
java
Object get_userData()
py
def get_userData()

This attribute is never touched directly by the API, and is at disposal of the caller to store a context.

Returns :

the object stored previously by the caller.

module→isOnline()module.isOnline()module.isOnline()module→isOnline()module→isOnline()[module isOnline]module.isOnline()module.isOnline()module.isOnline()module.isOnline()module.isOnline()

Checks if the module is currently reachable, without raising any error.

js
function isOnline()
nodejs
function isOnline()
php
function isOnline()
cpp
bool isOnline()
m
-(BOOL) isOnline
pas
function isOnline(): boolean
vb
function isOnline() As Boolean
cs
bool isOnline()
java
boolean isOnline()
py
def isOnline()

If there are valid cached values for the module, that have not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the requested module.

Returns :

true if the module can be reached, and false otherwise

module→isOnline_async()module.isOnline_async()module.isOnline_async()

Checks if the module is currently reachable, without raising any error.

js
function isOnline_async(callback, context)
nodejs
function isOnline_async(callback, context)

If there are valid cached values for the module, that have not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the requested module.

This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox Javascript VM that does not implement context switching during blocking I/O calls.

Parameters :

callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving module object and the boolean result
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

module→load()module.load()module.load()module→load()module→load()[module load: ]module.load()module.load()module.load()module.load()module.load()

Preloads the module cache with a specified validity duration.

js
function load(msValidity)
nodejs
function load(msValidity)
php
function load($msValidity)
cpp
YRETCODE load(int msValidity)
m
-(YRETCODE) load: (int) msValidity
pas
function load(msValidity: integer): YRETCODE
vb
function load(ByVal msValidity As Integer) As YRETCODE
cs
YRETCODE load(int msValidity)
java
int load(long msValidity)
py
def load(msValidity)

By default, whenever accessing a device, all module attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance.

Parameters :

msValidityan integer corresponding to the validity attributed to the loaded module parameters, in milliseconds

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

module→load_async()module.load_async()module.load_async()

Preloads the module cache with a specified validity duration (asynchronous version).

js
function load_async(msValidity, callback, context)
nodejs
function load_async(msValidity, callback, context)

By default, whenever accessing a device, all module attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox javascript VM that does not implement context switching during blocking I/O calls. See the documentation section on asynchronous Javascript calls for more details.

Parameters :

msValidityan integer corresponding to the validity of the loaded module parameters, in milliseconds
callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving module object and the error code (or YAPI_SUCCESS)
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

module→nextModule()module.nextModule()module.nextModule()module→nextModule()module→nextModule()[module nextModule]module.nextModule()module.nextModule()module.nextModule()module.nextModule()module.nextModule()

Continues the module enumeration started using yFirstModule().

js
function nextModule()
nodejs
function nextModule()
php
function nextModule()
cpp
YModule * nextModule()
m
-(YModule*) nextModule
pas
function nextModule(): TYModule
vb
function nextModule() As YModule
cs
YModule nextModule()
java
YModule nextModule()
py
def nextModule()

Returns :

a pointer to a YModule object, corresponding to the next module found, or a null pointer if there are no more modules to enumerate.

module→reboot()module.reboot()module.reboot()module→reboot()module→reboot()[module reboot: ]module.reboot()module.reboot()module.reboot()module.reboot()module.reboot()YModule reboot

Schedules a simple module reboot after the given number of seconds.

js
function reboot(secBeforeReboot)
nodejs
function reboot(secBeforeReboot)
php
function reboot($secBeforeReboot)
cpp
int reboot(int secBeforeReboot)
m
-(int) reboot: (int) secBeforeReboot
pas
function reboot(secBeforeReboot: LongInt): LongInt
vb
function reboot() As Integer
cs
int reboot(int secBeforeReboot)
java
int reboot(int secBeforeReboot)
py
def reboot(secBeforeReboot)
cmd
YModule target reboot secBeforeReboot

Parameters :

secBeforeRebootnumber of seconds before rebooting

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

module→revertFromFlash()module.revertFromFlash()module.revertFromFlash()module→revertFromFlash()module→revertFromFlash()[module revertFromFlash]module.revertFromFlash()module.revertFromFlash()module.revertFromFlash()module.revertFromFlash()module.revertFromFlash()YModule revertFromFlash

Reloads the settings stored in the nonvolatile memory, as when the module is powered on.

js
function revertFromFlash()
nodejs
function revertFromFlash()
php
function revertFromFlash()
cpp
int revertFromFlash()
m
-(int) revertFromFlash
pas
function revertFromFlash(): LongInt
vb
function revertFromFlash() As Integer
cs
int revertFromFlash()
java
int revertFromFlash()
py
def revertFromFlash()
cmd
YModule target revertFromFlash

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

module→saveToFlash()module.saveToFlash()module.saveToFlash()module→saveToFlash()module→saveToFlash()[module saveToFlash]module.saveToFlash()module.saveToFlash()module.saveToFlash()module.saveToFlash()module.saveToFlash()YModule saveToFlash

Saves current settings in the nonvolatile memory of the module.

js
function saveToFlash()
nodejs
function saveToFlash()
php
function saveToFlash()
cpp
int saveToFlash()
m
-(int) saveToFlash
pas
function saveToFlash(): LongInt
vb
function saveToFlash() As Integer
cs
int saveToFlash()
java
int saveToFlash()
py
def saveToFlash()
cmd
YModule target saveToFlash

Warning: the number of allowed save operations during a module life is limited (about 100000 cycles). Do not call this function within a loop.

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

module→set_beacon()
module→setBeacon()
module.set_beacon()module.set_beacon()module→set_beacon()module→set_beacon()[module setBeacon: ]module.set_beacon()module.set_beacon()module.set_beacon()module.set_beacon()module.set_beacon()YModule set_beacon

Turns on or off the module localization beacon.

js
function set_beacon(newval)
nodejs
function set_beacon(newval)
php
function set_beacon($newval)
cpp
int set_beacon(Y_BEACON_enum newval)
m
-(int) setBeacon: (Y_BEACON_enum) newval
pas
function set_beacon(newval: Integer): integer
vb
function set_beacon(ByVal newval As Integer) As Integer
cs
int set_beacon(int newval)
java
int set_beacon(int newval)
py
def set_beacon(newval)
cmd
YModule target set_beacon newval

Parameters :

newvaleither Y_BEACON_OFF or Y_BEACON_ON

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_logicalName()
module→setLogicalName()
module.set_logicalName()module.set_logicalName()module→set_logicalName()module→set_logicalName()[module setLogicalName: ]module.set_logicalName()module.set_logicalName()module.set_logicalName()module.set_logicalName()module.set_logicalName()YModule set_logicalName

Changes the logical name of the module.

js
function set_logicalName(newval)
nodejs
function set_logicalName(newval)
php
function set_logicalName($newval)
cpp
int set_logicalName(const string& newval)
m
-(int) setLogicalName: (NSString*) newval
pas
function set_logicalName(newval: string): integer
vb
function set_logicalName(ByVal newval As String) As Integer
cs
int set_logicalName(string newval)
java
int set_logicalName(String newval)
py
def set_logicalName(newval)
cmd
YModule target set_logicalName newval

You can use yCheckLogicalName() prior to this call to make sure that your parameter is valid. Remember to call the saveToFlash() method of the module if the modification must be kept.

Parameters :

newvala string corresponding to the logical name of the module

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_luminosity()
module→setLuminosity()
module.set_luminosity()module.set_luminosity()module→set_luminosity()module→set_luminosity()[module setLuminosity: ]module.set_luminosity()module.set_luminosity()module.set_luminosity()module.set_luminosity()module.set_luminosity()YModule set_luminosity

Changes the luminosity of the module informative leds.

js
function set_luminosity(newval)
nodejs
function set_luminosity(newval)
php
function set_luminosity($newval)
cpp
int set_luminosity(int newval)
m
-(int) setLuminosity: (int) newval
pas
function set_luminosity(newval: LongInt): integer
vb
function set_luminosity(ByVal newval As Integer) As Integer
cs
int set_luminosity(int newval)
java
int set_luminosity(int newval)
py
def set_luminosity(newval)
cmd
YModule target set_luminosity newval

The parameter is a value between 0 and 100. Remember to call the saveToFlash() method of the module if the modification must be kept.

Parameters :

newvalan integer corresponding to the luminosity of the module informative leds

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_usbBandwidth()
module→setUsbBandwidth()
module.set_usbBandwidth()module.set_usbBandwidth()module→set_usbBandwidth()module→set_usbBandwidth()[module setUsbBandwidth: ]module.set_usbBandwidth()module.set_usbBandwidth()module.set_usbBandwidth()module.set_usbBandwidth()module.set_usbBandwidth()YModule set_usbBandwidth

Changes the number of USB interfaces used by the module.

js
function set_usbBandwidth(newval)
nodejs
function set_usbBandwidth(newval)
php
function set_usbBandwidth($newval)
cpp
int set_usbBandwidth(Y_USBBANDWIDTH_enum newval)
m
-(int) setUsbBandwidth: (Y_USBBANDWIDTH_enum) newval
pas
function set_usbBandwidth(newval: Integer): integer
vb
function set_usbBandwidth(ByVal newval As Integer) As Integer
cs
int set_usbBandwidth(int newval)
java
int set_usbBandwidth(int newval)
py
def set_usbBandwidth(newval)
cmd
YModule target set_usbBandwidth newval

You must reboot the module after changing this setting.

Parameters :

newvaleither Y_USBBANDWIDTH_SIMPLE or Y_USBBANDWIDTH_DOUBLE, according to the number of USB interfaces used by the module

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

module→set_userData()
module→setUserData()
module.set_userData()module.set_userData()module→set_userData()module→set_userData()[module setUserData: ]module.set_userData()module.set_userData()module.set_userData()module.set_userData()module.set_userData()

Stores a user context provided as argument in the userData attribute of the function.

js
function set_userData(data)
nodejs
function set_userData(data)
php
function set_userData($data)
cpp
void set_userData(void* data)
m
-(void) setUserData: (void*) data
pas
procedure set_userData(data: Tobject)
vb
procedure set_userData(ByVal data As Object)
cs
void set_userData(object data)
java
void set_userData(Object data)
py
def set_userData(data)

This attribute is never touched by the API, and is at disposal of the caller to store a context.

Parameters :

dataany kind of object to be stored

module→triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module→triggerFirmwareUpdate()module→triggerFirmwareUpdate()[module triggerFirmwareUpdate: ]module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()module.triggerFirmwareUpdate()YModule triggerFirmwareUpdate

Schedules a module reboot into special firmware update mode.

js
function triggerFirmwareUpdate(secBeforeReboot)
nodejs
function triggerFirmwareUpdate(secBeforeReboot)
php
function triggerFirmwareUpdate($secBeforeReboot)
cpp
int triggerFirmwareUpdate(int secBeforeReboot)
m
-(int) triggerFirmwareUpdate: (int) secBeforeReboot
pas
function triggerFirmwareUpdate(secBeforeReboot: LongInt): LongInt
vb
function triggerFirmwareUpdate() As Integer
cs
int triggerFirmwareUpdate(int secBeforeReboot)
java
int triggerFirmwareUpdate(int secBeforeReboot)
py
def triggerFirmwareUpdate(secBeforeReboot)
cmd
YModule target triggerFirmwareUpdate secBeforeReboot

Parameters :

secBeforeRebootnumber of seconds before rebooting

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

module→wait_async()module.wait_async()module.wait_async()

Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.

js
function wait_async(callback, context)
nodejs
function wait_async(callback, context)

The callback function can therefore freely issue synchronous or asynchronous commands, without risking to block the Javascript VM.

Parameters :

callbackcallback function that is invoked when all pending commands on the module are completed. The callback function receives two arguments: the caller-specific context object and the receiving function object.
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing.

20.3. Relay function interface

The Yoctopuce application programming interface allows you to switch the relay state. This change is not persistent: the relay will automatically return to its idle position whenever power is lost or if the module is restarted. The library can also generate automatically short pulses of determined duration. On devices with two output for each relay (double throw), the two outputs are named A and B, with output A corresponding to the idle position (at power off) and the output B corresponding to the active state. If you prefer the alternate default state, simply switch your cables on the board.

In order to use the functions described here, you should include:

js
<script type='text/javascript' src='yocto_relay.js'></script>
nodejs
var yoctolib = require('yoctolib');
var YRelay = yoctolib.YRelay;
php
require_once('yocto_relay.php');
cpp
#include "yocto_relay.h"
m
#import "yocto_relay.h"
pas
uses yocto_relay;
vb
yocto_relay.vb
cs
yocto_relay.cs
java
import com.yoctopuce.YoctoAPI.YRelay;
py
from yocto_relay import *
Global functions
yFindRelay(func)

Retrieves a relay for a given identifier.

yFirstRelay()

Starts the enumeration of relays currently accessible.

YRelay methods
relay→delayedPulse(ms_delay, ms_duration)

Schedules a pulse.

relay→describe()

Returns a short text that describes the relay in the form TYPE(NAME)=SERIAL.FUNCTIONID.

relay→get_advertisedValue()

Returns the current value of the relay (no more than 6 characters).

relay→get_countdown()

Returns the number of milliseconds remaining before a pulse (delayedPulse() call) When there is no scheduled pulse, returns zero.

relay→get_errorMessage()

Returns the error message of the latest error with the relay.

relay→get_errorType()

Returns the numerical error code of the latest error with the relay.

relay→get_friendlyName()

Returns a global identifier of the relay in the format MODULE_NAME.FUNCTION_NAME.

relay→get_functionDescriptor()

Returns a unique identifier of type YFUN_DESCR corresponding to the function.

relay→get_functionId()

Returns the hardware identifier of the relay, without reference to the module.

relay→get_hardwareId()

Returns the unique hardware identifier of the relay in the form SERIAL.FUNCTIONID.

relay→get_logicalName()

Returns the logical name of the relay.

relay→get_maxTimeOnStateA()

Retourne the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state A before automatically switching back in to B state.

relay→get_maxTimeOnStateB()

Retourne the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state B before automatically switching back in to A state.

relay→get_module()

Gets the YModule object for the device on which the function is located.

relay→get_module_async(callback, context)

Gets the YModule object for the device on which the function is located (asynchronous version).

relay→get_output()

Returns the output state of the relays, when used as a simple switch (single throw).

relay→get_pulseTimer()

Returns the number of milliseconds remaining before the relays is returned to idle position (state A), during a measured pulse generation.

relay→get_state()

Returns the state of the relays (A for the idle position, B for the active position).

relay→get_stateAtPowerOn()

Returns the state of the relays at device startup (A for the idle position, B for the active position, UNCHANGED for no change).

relay→get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

relay→isOnline()

Checks if the relay is currently reachable, without raising any error.

relay→isOnline_async(callback, context)

Checks if the relay is currently reachable, without raising any error (asynchronous version).

relay→load(msValidity)

Preloads the relay cache with a specified validity duration.

relay→load_async(msValidity, callback, context)

Preloads the relay cache with a specified validity duration (asynchronous version).

relay→nextRelay()

Continues the enumeration of relays started using yFirstRelay().

relay→pulse(ms_duration)

Sets the relay to output B (active) for a specified duration, then brings it automatically back to output A (idle state).

relay→registerValueCallback(callback)

Registers the callback function that is invoked on every change of advertised value.

relay→set_logicalName(newval)

Changes the logical name of the relay.

relay→set_maxTimeOnStateA(newval)

Sets the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state A before automatically switching back in to B state.

relay→set_maxTimeOnStateB(newval)

Sets the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state B before automatically switching back in to A state.

relay→set_output(newval)

Changes the output state of the relays, when used as a simple switch (single throw).

relay→set_state(newval)

Changes the state of the relays (A for the idle position, B for the active position).

relay→set_stateAtPowerOn(newval)

Preset the state of the relays at device startup (A for the idle position, B for the active position, UNCHANGED for no modification).

relay→set_userData(data)

Stores a user context provided as argument in the userData attribute of the function.

relay→wait_async(callback, context)

Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.

YRelay.FindRelay()
yFindRelay()
yFindRelay()YRelay.FindRelay()yFindRelay()yFindRelay()yFindRelay()yFindRelay()yFindRelay()YRelay.FindRelay()YRelay.FindRelay()YRelay.FindRelay()

Retrieves a relay for a given identifier.

js
function yFindRelay(func)
nodejs
function FindRelay(func)
php
function yFindRelay($func)
cpp
YRelay* yFindRelay(const string& func)
m
YRelay* yFindRelay(NSString* func)
pas
function yFindRelay(func: string): TYRelay
vb
function yFindRelay(ByVal func As String) As YRelay
cs
YRelay FindRelay(string func)
java
YRelay FindRelay(String func)
py
def FindRelay(func)

The identifier can be specified using several formats:

This function does not require that the relay is online at the time it is invoked. The returned object is nevertheless valid. Use the method YRelay.isOnline() to test if the relay is indeed online at a given time. In case of ambiguity when looking for a relay by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.

Parameters :

funca string that uniquely characterizes the relay

Returns :

a YRelay object allowing you to drive the relay.

YRelay.FirstRelay()
yFirstRelay()
yFirstRelay()YRelay.FirstRelay()yFirstRelay()yFirstRelay()yFirstRelay()yFirstRelay()yFirstRelay()YRelay.FirstRelay()YRelay.FirstRelay()YRelay.FirstRelay()

Starts the enumeration of relays currently accessible.

js
function yFirstRelay()
nodejs
function FirstRelay()
php
function yFirstRelay()
cpp
YRelay* yFirstRelay()
m
YRelay* yFirstRelay()
pas
function yFirstRelay(): TYRelay
vb
function yFirstRelay() As YRelay
cs
YRelay FirstRelay()
java
YRelay FirstRelay()
py
def FirstRelay()

Use the method YRelay.nextRelay() to iterate on next relays.

Returns :

a pointer to a YRelay object, corresponding to the first relay currently online, or a null pointer if there are none.

relay→delayedPulse()relay.delayedPulse()relay.delayedPulse()relay→delayedPulse()relay→delayedPulse()[relay delayedPulse: ]relay.delayedPulse()relay.delayedPulse()relay.delayedPulse()relay.delayedPulse()relay.delayedPulse()YRelay delayedPulse

Schedules a pulse.

js
function delayedPulse(ms_delay, ms_duration)
nodejs
function delayedPulse(ms_delay, ms_duration)
php
function delayedPulse($ms_delay, $ms_duration)
cpp
int delayedPulse(int ms_delay, int ms_duration)
m
-(int) delayedPulse: (int) ms_delay : (int) ms_duration
pas
function delayedPulse(ms_delay: LongInt, ms_duration: LongInt): integer
vb
function delayedPulse(ByVal ms_delay As Integer,
  ByVal ms_duration As Integer) As Integer
cs
int delayedPulse(int ms_delay, int ms_duration)
java
int delayedPulse(int ms_delay, int ms_duration)
py
def delayedPulse(ms_delay, ms_duration)
cmd
YRelay target delayedPulse ms_delay ms_duration

Parameters :

ms_delaywaiting time before the pulse, in millisecondes
ms_durationpulse duration, in millisecondes

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→describe()relay.describe()relay.describe()relay→describe()relay→describe()[relay describe]relay.describe()relay.describe()relay.describe()relay.describe()relay.describe()

Returns a short text that describes the relay in the form TYPE(NAME)=SERIAL.FUNCTIONID.

js
function describe()
nodejs
function describe()
php
function describe()
cpp
string describe()
m
-(NSString*) describe
pas
function describe(): string
vb
function describe() As String
cs
string describe()
java
String describe()
py
def describe()

More precisely, TYPE is the type of the function, NAME it the name used for the first access to the function, SERIAL is the serial number of the module if the module is connected or "unresolved", and FUNCTIONID is the hardware identifier of the function if the module is connected. For example, this method returns Relay(MyCustomName.relay1)=RELAYLO1-123456.relay1 if the module is already connected or Relay(BadCustomeName.relay1)=unresolved if the module has not yet been connected. This method does not trigger any USB or TCP transaction and can therefore be used in a debugger.

Returns :

a string that describes the relay (ex: Relay(MyCustomName.relay1)=RELAYLO1-123456.relay1)

relay→get_advertisedValue()
relay→advertisedValue()
relay.get_advertisedValue()relay.get_advertisedValue()relay→get_advertisedValue()relay→get_advertisedValue()[relay advertisedValue]relay.get_advertisedValue()relay.get_advertisedValue()relay.get_advertisedValue()relay.get_advertisedValue()relay.get_advertisedValue()YRelay get_advertisedValue

Returns the current value of the relay (no more than 6 characters).

js
function get_advertisedValue()
nodejs
function get_advertisedValue()
php
function get_advertisedValue()
cpp
string get_advertisedValue()
m
-(NSString*) advertisedValue
pas
function get_advertisedValue(): string
vb
function get_advertisedValue() As String
cs
string get_advertisedValue()
java
String get_advertisedValue()
py
def get_advertisedValue()
cmd
YRelay target get_advertisedValue

Returns :

a string corresponding to the current value of the relay (no more than 6 characters). On failure, throws an exception or returns Y_ADVERTISEDVALUE_INVALID.

relay→get_countdown()
relay→countdown()
relay.get_countdown()relay.get_countdown()relay→get_countdown()relay→get_countdown()[relay countdown]relay.get_countdown()relay.get_countdown()relay.get_countdown()relay.get_countdown()relay.get_countdown()YRelay get_countdown

Returns the number of milliseconds remaining before a pulse (delayedPulse() call) When there is no scheduled pulse, returns zero.

js
function get_countdown()
nodejs
function get_countdown()
php
function get_countdown()
cpp
s64 get_countdown()
m
-(s64) countdown
pas
function get_countdown(): int64
vb
function get_countdown() As Long
cs
long get_countdown()
java
long get_countdown()
py
def get_countdown()
cmd
YRelay target get_countdown

Returns :

an integer corresponding to the number of milliseconds remaining before a pulse (delayedPulse() call) When there is no scheduled pulse, returns zero

On failure, throws an exception or returns Y_COUNTDOWN_INVALID.

relay→get_errorMessage()
relay→errorMessage()
relay.get_errorMessage()relay.get_errorMessage()relay→get_errorMessage()relay→get_errorMessage()[relay errorMessage]relay.get_errorMessage()relay.get_errorMessage()relay.get_errorMessage()relay.get_errorMessage()relay.get_errorMessage()

Returns the error message of the latest error with the relay.

js
function get_errorMessage()
nodejs
function get_errorMessage()
php
function get_errorMessage()
cpp
string get_errorMessage()
m
-(NSString*) errorMessage
pas
function get_errorMessage(): string
vb
function get_errorMessage() As String
cs
string get_errorMessage()
java
String get_errorMessage()
py
def get_errorMessage()

This method is mostly useful when using the Yoctopuce library with exceptions disabled.

Returns :

a string corresponding to the latest error message that occured while using the relay object

relay→get_errorType()
relay→errorType()
relay.get_errorType()relay.get_errorType()relay→get_errorType()relay→get_errorType()relay.get_errorType()relay.get_errorType()relay.get_errorType()relay.get_errorType()relay.get_errorType()

Returns the numerical error code of the latest error with the relay.

js
function get_errorType()
nodejs
function get_errorType()
php
function get_errorType()
cpp
YRETCODE get_errorType()
pas
function get_errorType(): YRETCODE
vb
function get_errorType() As YRETCODE
cs
YRETCODE get_errorType()
java
int get_errorType()
py
def get_errorType()

This method is mostly useful when using the Yoctopuce library with exceptions disabled.

Returns :

a number corresponding to the code of the latest error that occured while using the relay object

relay→get_friendlyName()
relay→friendlyName()
relay.get_friendlyName()relay.get_friendlyName()relay→get_friendlyName()relay→get_friendlyName()[relay friendlyName]relay.get_friendlyName()relay.get_friendlyName()relay.get_friendlyName()

Returns a global identifier of the relay in the format MODULE_NAME.FUNCTION_NAME.

js
function get_friendlyName()
nodejs
function get_friendlyName()
php
function get_friendlyName()
cpp
string get_friendlyName()
m
-(NSString*) friendlyName
cs
string get_friendlyName()
java
String get_friendlyName()
py
def get_friendlyName()

The returned string uses the logical names of the module and of the relay if they are defined, otherwise the serial number of the module and the hardware identifier of the relay (for exemple: MyCustomName.relay1)

Returns :

a string that uniquely identifies the relay using logical names (ex: MyCustomName.relay1) On failure, throws an exception or returns Y_FRIENDLYNAME_INVALID.

relay→get_functionDescriptor()
relay→functionDescriptor()
relay.get_functionDescriptor()relay.get_functionDescriptor()relay→get_functionDescriptor()relay→get_functionDescriptor()[relay functionDescriptor]relay.get_functionDescriptor()relay.get_functionDescriptor()relay.get_functionDescriptor()relay.get_functionDescriptor()relay.get_functionDescriptor()

Returns a unique identifier of type YFUN_DESCR corresponding to the function.

js
function get_functionDescriptor()
nodejs
function get_functionDescriptor()
php
function get_functionDescriptor()
cpp
YFUN_DESCR get_functionDescriptor()
m
-(YFUN_DESCR) functionDescriptor
pas
function get_functionDescriptor(): YFUN_DESCR
vb
function get_functionDescriptor() As YFUN_DESCR
cs
YFUN_DESCR get_functionDescriptor()
java
String get_functionDescriptor()
py
def get_functionDescriptor()

This identifier can be used to test if two instances of YFunction reference the same physical function on the same physical device.

Returns :

an identifier of type YFUN_DESCR. If the function has never been contacted, the returned value is Y_FUNCTIONDESCRIPTOR_INVALID.

relay→get_functionId()
relay→functionId()
relay.get_functionId()relay.get_functionId()relay→get_functionId()relay→get_functionId()[relay functionId]relay.get_functionId()relay.get_functionId()relay.get_functionId()relay.get_functionId()

Returns the hardware identifier of the relay, without reference to the module.

js
function get_functionId()
nodejs
function get_functionId()
php
function get_functionId()
cpp
string get_functionId()
m
-(NSString*) functionId
vb
function get_functionId() As String
cs
string get_functionId()
java
String get_functionId()
py
def get_functionId()

For example relay1

Returns :

a string that identifies the relay (ex: relay1) On failure, throws an exception or returns Y_FUNCTIONID_INVALID.

relay→get_hardwareId()
relay→hardwareId()
relay.get_hardwareId()relay.get_hardwareId()relay→get_hardwareId()relay→get_hardwareId()[relay hardwareId]relay.get_hardwareId()relay.get_hardwareId()relay.get_hardwareId()relay.get_hardwareId()

Returns the unique hardware identifier of the relay in the form SERIAL.FUNCTIONID.

js
function get_hardwareId()
nodejs
function get_hardwareId()
php
function get_hardwareId()
cpp
string get_hardwareId()
m
-(NSString*) hardwareId
vb
function get_hardwareId() As String
cs
string get_hardwareId()
java
String get_hardwareId()
py
def get_hardwareId()

The unique hardware identifier is composed of the device serial number and of the hardware identifier of the relay. (for example RELAYLO1-123456.relay1)

Returns :

a string that uniquely identifies the relay (ex: RELAYLO1-123456.relay1) On failure, throws an exception or returns Y_HARDWAREID_INVALID.

relay→get_logicalName()
relay→logicalName()
relay.get_logicalName()relay.get_logicalName()relay→get_logicalName()relay→get_logicalName()[relay logicalName]relay.get_logicalName()relay.get_logicalName()relay.get_logicalName()relay.get_logicalName()relay.get_logicalName()YRelay get_logicalName

Returns the logical name of the relay.

js
function get_logicalName()
nodejs
function get_logicalName()
php
function get_logicalName()
cpp
string get_logicalName()
m
-(NSString*) logicalName
pas
function get_logicalName(): string
vb
function get_logicalName() As String
cs
string get_logicalName()
java
String get_logicalName()
py
def get_logicalName()
cmd
YRelay target get_logicalName

Returns :

a string corresponding to the logical name of the relay. On failure, throws an exception or returns Y_LOGICALNAME_INVALID.

relay→get_maxTimeOnStateA()
relay→maxTimeOnStateA()
relay.get_maxTimeOnStateA()relay.get_maxTimeOnStateA()relay→get_maxTimeOnStateA()relay→get_maxTimeOnStateA()[relay maxTimeOnStateA]relay.get_maxTimeOnStateA()relay.get_maxTimeOnStateA()relay.get_maxTimeOnStateA()relay.get_maxTimeOnStateA()relay.get_maxTimeOnStateA()YRelay get_maxTimeOnStateA

Retourne the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state A before automatically switching back in to B state.

js
function get_maxTimeOnStateA()
nodejs
function get_maxTimeOnStateA()
php
function get_maxTimeOnStateA()
cpp
s64 get_maxTimeOnStateA()
m
-(s64) maxTimeOnStateA
pas
function get_maxTimeOnStateA(): int64
vb
function get_maxTimeOnStateA() As Long
cs
long get_maxTimeOnStateA()
java
long get_maxTimeOnStateA()
py
def get_maxTimeOnStateA()
cmd
YRelay target get_maxTimeOnStateA

Zero means no maximum time.

Returns :

an integer

On failure, throws an exception or returns Y_MAXTIMEONSTATEA_INVALID.

relay→get_maxTimeOnStateB()
relay→maxTimeOnStateB()
relay.get_maxTimeOnStateB()relay.get_maxTimeOnStateB()relay→get_maxTimeOnStateB()relay→get_maxTimeOnStateB()[relay maxTimeOnStateB]relay.get_maxTimeOnStateB()relay.get_maxTimeOnStateB()relay.get_maxTimeOnStateB()relay.get_maxTimeOnStateB()relay.get_maxTimeOnStateB()YRelay get_maxTimeOnStateB

Retourne the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state B before automatically switching back in to A state.

js
function get_maxTimeOnStateB()
nodejs
function get_maxTimeOnStateB()
php
function get_maxTimeOnStateB()
cpp
s64 get_maxTimeOnStateB()
m
-(s64) maxTimeOnStateB
pas
function get_maxTimeOnStateB(): int64
vb
function get_maxTimeOnStateB() As Long
cs
long get_maxTimeOnStateB()
java
long get_maxTimeOnStateB()
py
def get_maxTimeOnStateB()
cmd
YRelay target get_maxTimeOnStateB

Zero means no maximum time.

Returns :

an integer

On failure, throws an exception or returns Y_MAXTIMEONSTATEB_INVALID.

relay→get_module()
relay→module()
relay.get_module()relay.get_module()relay→get_module()relay→get_module()[relay module]relay.get_module()relay.get_module()relay.get_module()relay.get_module()relay.get_module()

Gets the YModule object for the device on which the function is located.

js
function get_module()
nodejs
function get_module()
php
function get_module()
cpp
YModule * get_module()
m
-(YModule*) module
pas
function get_module(): TYModule
vb
function get_module() As YModule
cs
YModule get_module()
java
YModule get_module()
py
def get_module()

If the function cannot be located on any module, the returned instance of YModule is not shown as on-line.

Returns :

an instance of YModule

relay→get_module_async()
relay→module_async()
relay.get_module_async()relay.get_module_async()

Gets the YModule object for the device on which the function is located (asynchronous version).

js
function get_module_async(callback, context)
nodejs
function get_module_async(callback, context)

If the function cannot be located on any module, the returned YModule object does not show as on-line. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox javascript VM that does not implement context switching during blocking I/O calls. See the documentation section on asynchronous Javascript calls for more details.

Parameters :

callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the requested YModule object
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

relay→get_output()
relay→output()
relay.get_output()relay.get_output()relay→get_output()relay→get_output()[relay output]relay.get_output()relay.get_output()relay.get_output()relay.get_output()relay.get_output()YRelay get_output

Returns the output state of the relays, when used as a simple switch (single throw).

js
function get_output()
nodejs
function get_output()
php
function get_output()
cpp
Y_OUTPUT_enum get_output()
m
-(Y_OUTPUT_enum) output
pas
function get_output(): Integer
vb
function get_output() As Integer
cs
int get_output()
java
int get_output()
py
def get_output()
cmd
YRelay target get_output

Returns :

either Y_OUTPUT_OFF or Y_OUTPUT_ON, according to the output state of the relays, when used as a simple switch (single throw)

On failure, throws an exception or returns Y_OUTPUT_INVALID.

relay→get_pulseTimer()
relay→pulseTimer()
relay.get_pulseTimer()relay.get_pulseTimer()relay→get_pulseTimer()relay→get_pulseTimer()[relay pulseTimer]relay.get_pulseTimer()relay.get_pulseTimer()relay.get_pulseTimer()relay.get_pulseTimer()relay.get_pulseTimer()YRelay get_pulseTimer

Returns the number of milliseconds remaining before the relays is returned to idle position (state A), during a measured pulse generation.

js
function get_pulseTimer()
nodejs
function get_pulseTimer()
php
function get_pulseTimer()
cpp
s64 get_pulseTimer()
m
-(s64) pulseTimer
pas
function get_pulseTimer(): int64
vb
function get_pulseTimer() As Long
cs
long get_pulseTimer()
java
long get_pulseTimer()
py
def get_pulseTimer()
cmd
YRelay target get_pulseTimer

When there is no ongoing pulse, returns zero.

Returns :

an integer corresponding to the number of milliseconds remaining before the relays is returned to idle position (state A), during a measured pulse generation

On failure, throws an exception or returns Y_PULSETIMER_INVALID.

relay→get_state()
relay→state()
relay.get_state()relay.get_state()relay→get_state()relay→get_state()[relay state]relay.get_state()relay.get_state()relay.get_state()relay.get_state()relay.get_state()YRelay get_state

Returns the state of the relays (A for the idle position, B for the active position).

js
function get_state()
nodejs
function get_state()
php
function get_state()
cpp
Y_STATE_enum get_state()
m
-(Y_STATE_enum) state
pas
function get_state(): Integer
vb
function get_state() As Integer
cs
int get_state()
java
int get_state()
py
def get_state()
cmd
YRelay target get_state

Returns :

either Y_STATE_A or Y_STATE_B, according to the state of the relays (A for the idle position, B for the active position)

On failure, throws an exception or returns Y_STATE_INVALID.

relay→get_stateAtPowerOn()
relay→stateAtPowerOn()
relay.get_stateAtPowerOn()relay.get_stateAtPowerOn()relay→get_stateAtPowerOn()relay→get_stateAtPowerOn()[relay stateAtPowerOn]relay.get_stateAtPowerOn()relay.get_stateAtPowerOn()relay.get_stateAtPowerOn()relay.get_stateAtPowerOn()relay.get_stateAtPowerOn()YRelay get_stateAtPowerOn

Returns the state of the relays at device startup (A for the idle position, B for the active position, UNCHANGED for no change).

js
function get_stateAtPowerOn()
nodejs
function get_stateAtPowerOn()
php
function get_stateAtPowerOn()
cpp
Y_STATEATPOWERON_enum get_stateAtPowerOn()
m
-(Y_STATEATPOWERON_enum) stateAtPowerOn
pas
function get_stateAtPowerOn(): Integer
vb
function get_stateAtPowerOn() As Integer
cs
int get_stateAtPowerOn()
java
int get_stateAtPowerOn()
py
def get_stateAtPowerOn()
cmd
YRelay target get_stateAtPowerOn

Returns :

a value among Y_STATEATPOWERON_UNCHANGED, Y_STATEATPOWERON_A and Y_STATEATPOWERON_B corresponding to the state of the relays at device startup (A for the idle position, B for the active position, UNCHANGED for no change)

On failure, throws an exception or returns Y_STATEATPOWERON_INVALID.

relay→get_userData()
relay→userData()
relay.get_userData()relay.get_userData()relay→get_userData()relay→get_userData()[relay userData]relay.get_userData()relay.get_userData()relay.get_userData()relay.get_userData()relay.get_userData()

Returns the value of the userData attribute, as previously stored using method set_userData.

js
function get_userData()
nodejs
function get_userData()
php
function get_userData()
cpp
void * get_userData()
m
-(void*) userData
pas
function get_userData(): Tobject
vb
function get_userData() As Object
cs
object get_userData()
java
Object get_userData()
py
def get_userData()

This attribute is never touched directly by the API, and is at disposal of the caller to store a context.

Returns :

the object stored previously by the caller.

relay→isOnline()relay.isOnline()relay.isOnline()relay→isOnline()relay→isOnline()[relay isOnline]relay.isOnline()relay.isOnline()relay.isOnline()relay.isOnline()relay.isOnline()

Checks if the relay is currently reachable, without raising any error.

js
function isOnline()
nodejs
function isOnline()
php
function isOnline()
cpp
bool isOnline()
m
-(BOOL) isOnline
pas
function isOnline(): boolean
vb
function isOnline() As Boolean
cs
bool isOnline()
java
boolean isOnline()
py
def isOnline()

If there is a cached value for the relay in cache, that has not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the device hosting the relay.

Returns :

true if the relay can be reached, and false otherwise

relay→isOnline_async()relay.isOnline_async()relay.isOnline_async()

Checks if the relay is currently reachable, without raising any error (asynchronous version).

js
function isOnline_async(callback, context)
nodejs
function isOnline_async(callback, context)

If there is a cached value for the relay in cache, that has not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the device hosting the requested function.

This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking the Javascript virtual machine.

Parameters :

callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the boolean result
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

relay→load()relay.load()relay.load()relay→load()relay→load()[relay load: ]relay.load()relay.load()relay.load()relay.load()relay.load()

Preloads the relay cache with a specified validity duration.

js
function load(msValidity)
nodejs
function load(msValidity)
php
function load($msValidity)
cpp
YRETCODE load(int msValidity)
m
-(YRETCODE) load: (int) msValidity
pas
function load(msValidity: integer): YRETCODE
vb
function load(ByVal msValidity As Integer) As YRETCODE
cs
YRETCODE load(int msValidity)
java
int load(long msValidity)
py
def load(msValidity)

By default, whenever accessing a device, all function attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance.

Parameters :

msValidityan integer corresponding to the validity attributed to the loaded function parameters, in milliseconds

Returns :

YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.

relay→load_async()relay.load_async()relay.load_async()

Preloads the relay cache with a specified validity duration (asynchronous version).

js
function load_async(msValidity, callback, context)
nodejs
function load_async(msValidity, callback, context)

By default, whenever accessing a device, all function attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking the Javascript virtual machine.

Parameters :

msValidityan integer corresponding to the validity of the loaded function parameters, in milliseconds
callbackcallback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the error code (or YAPI_SUCCESS)
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing : the result is provided to the callback.

relay→nextRelay()relay.nextRelay()relay.nextRelay()relay→nextRelay()relay→nextRelay()[relay nextRelay]relay.nextRelay()relay.nextRelay()relay.nextRelay()relay.nextRelay()relay.nextRelay()

Continues the enumeration of relays started using yFirstRelay().

js
function nextRelay()
nodejs
function nextRelay()
php
function nextRelay()
cpp
YRelay * nextRelay()
m
-(YRelay*) nextRelay
pas
function nextRelay(): TYRelay
vb
function nextRelay() As YRelay
cs
YRelay nextRelay()
java
YRelay nextRelay()
py
def nextRelay()

Returns :

a pointer to a YRelay object, corresponding to a relay currently online, or a null pointer if there are no more relays to enumerate.

relay→pulse()relay.pulse()relay.pulse()relay→pulse()relay→pulse()[relay pulse: ]relay.pulse()relay.pulse()relay.pulse()relay.pulse()relay.pulse()YRelay pulse

Sets the relay to output B (active) for a specified duration, then brings it automatically back to output A (idle state).

js
function pulse(ms_duration)
nodejs
function pulse(ms_duration)
php
function pulse($ms_duration)
cpp
int pulse(int ms_duration)
m
-(int) pulse: (int) ms_duration
pas
function pulse(ms_duration: LongInt): integer
vb
function pulse(ByVal ms_duration As Integer) As Integer
cs
int pulse(int ms_duration)
java
int pulse(int ms_duration)
py
def pulse(ms_duration)
cmd
YRelay target pulse ms_duration

Parameters :

ms_durationpulse duration, in millisecondes

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→registerValueCallback()relay.registerValueCallback()relay.registerValueCallback()relay→registerValueCallback()relay→registerValueCallback()[relay registerValueCallback: ]relay.registerValueCallback()relay.registerValueCallback()relay.registerValueCallback()relay.registerValueCallback()relay.registerValueCallback()

Registers the callback function that is invoked on every change of advertised value.

js
function registerValueCallback(callback)
nodejs
function registerValueCallback(callback)
php
function registerValueCallback($callback)
cpp
int registerValueCallback(YRelayValueCallback callback)
m
-(int) registerValueCallback: (YRelayValueCallback) callback
pas
function registerValueCallback(callback: TYRelayValueCallback): LongInt
vb
function registerValueCallback() As Integer
cs
int registerValueCallback(ValueCallback callback)
java
int registerValueCallback(UpdateCallback callback)
py
def registerValueCallback(callback)

The callback is invoked only during the execution of ySleep or yHandleEvents. This provides control over the time when the callback is triggered. For good responsiveness, remember to call one of these two functions periodically. To unregister a callback, pass a null pointer as argument.

Parameters :

callbackthe callback function to call, or a null pointer. The callback function should take two arguments: the function object of which the value has changed, and the character string describing the new advertised value.

relay→set_logicalName()
relay→setLogicalName()
relay.set_logicalName()relay.set_logicalName()relay→set_logicalName()relay→set_logicalName()[relay setLogicalName: ]relay.set_logicalName()relay.set_logicalName()relay.set_logicalName()relay.set_logicalName()relay.set_logicalName()YRelay set_logicalName

Changes the logical name of the relay.

js
function set_logicalName(newval)
nodejs
function set_logicalName(newval)
php
function set_logicalName($newval)
cpp
int set_logicalName(const string& newval)
m
-(int) setLogicalName: (NSString*) newval
pas
function set_logicalName(newval: string): integer
vb
function set_logicalName(ByVal newval As String) As Integer
cs
int set_logicalName(string newval)
java
int set_logicalName(String newval)
py
def set_logicalName(newval)
cmd
YRelay target set_logicalName newval

You can use yCheckLogicalName() prior to this call to make sure that your parameter is valid. Remember to call the saveToFlash() method of the module if the modification must be kept.

Parameters :

newvala string corresponding to the logical name of the relay.

Returns :

YAPI_SUCCESS if the call succeeds. On failure, throws an exception or returns a negative error code.

relay→set_maxTimeOnStateA()
relay→setMaxTimeOnStateA()
relay.set_maxTimeOnStateA()relay.set_maxTimeOnStateA()relay→set_maxTimeOnStateA()relay→set_maxTimeOnStateA()[relay setMaxTimeOnStateA: ]relay.set_maxTimeOnStateA()relay.set_maxTimeOnStateA()relay.set_maxTimeOnStateA()relay.set_maxTimeOnStateA()relay.set_maxTimeOnStateA()YRelay set_maxTimeOnStateA

Sets the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state A before automatically switching back in to B state.

js
function set_maxTimeOnStateA(newval)
nodejs
function set_maxTimeOnStateA(newval)
php
function set_maxTimeOnStateA($newval)
cpp
int set_maxTimeOnStateA(s64 newval)
m
-(int) setMaxTimeOnStateA: (s64) newval
pas
function set_maxTimeOnStateA(newval: int64): integer
vb
function set_maxTimeOnStateA(ByVal newval As Long) As Integer
cs
int set_maxTimeOnStateA(long newval)
java
int set_maxTimeOnStateA(long newval)
py
def set_maxTimeOnStateA(newval)
cmd
YRelay target set_maxTimeOnStateA newval

Use zero for no maximum time.

Parameters :

newvalan integer

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→set_maxTimeOnStateB()
relay→setMaxTimeOnStateB()
relay.set_maxTimeOnStateB()relay.set_maxTimeOnStateB()relay→set_maxTimeOnStateB()relay→set_maxTimeOnStateB()[relay setMaxTimeOnStateB: ]relay.set_maxTimeOnStateB()relay.set_maxTimeOnStateB()relay.set_maxTimeOnStateB()relay.set_maxTimeOnStateB()relay.set_maxTimeOnStateB()YRelay set_maxTimeOnStateB

Sets the maximum time (ms) allowed for $THEFUNCTIONS$ to stay in state B before automatically switching back in to A state.

js
function set_maxTimeOnStateB(newval)
nodejs
function set_maxTimeOnStateB(newval)
php
function set_maxTimeOnStateB($newval)
cpp
int set_maxTimeOnStateB(s64 newval)
m
-(int) setMaxTimeOnStateB: (s64) newval
pas
function set_maxTimeOnStateB(newval: int64): integer
vb
function set_maxTimeOnStateB(ByVal newval As Long) As Integer
cs
int set_maxTimeOnStateB(long newval)
java
int set_maxTimeOnStateB(long newval)
py
def set_maxTimeOnStateB(newval)
cmd
YRelay target set_maxTimeOnStateB newval

Use zero for no maximum time.

Parameters :

newvalan integer

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→set_output()
relay→setOutput()
relay.set_output()relay.set_output()relay→set_output()relay→set_output()[relay setOutput: ]relay.set_output()relay.set_output()relay.set_output()relay.set_output()relay.set_output()YRelay set_output

Changes the output state of the relays, when used as a simple switch (single throw).

js
function set_output(newval)
nodejs
function set_output(newval)
php
function set_output($newval)
cpp
int set_output(Y_OUTPUT_enum newval)
m
-(int) setOutput: (Y_OUTPUT_enum) newval
pas
function set_output(newval: Integer): integer
vb
function set_output(ByVal newval As Integer) As Integer
cs
int set_output(int newval)
java
int set_output(int newval)
py
def set_output(newval)
cmd
YRelay target set_output newval

Parameters :

newvaleither Y_OUTPUT_OFF or Y_OUTPUT_ON, according to the output state of the relays, when used as a simple switch (single throw)

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→set_state()
relay→setState()
relay.set_state()relay.set_state()relay→set_state()relay→set_state()[relay setState: ]relay.set_state()relay.set_state()relay.set_state()relay.set_state()relay.set_state()YRelay set_state

Changes the state of the relays (A for the idle position, B for the active position).

js
function set_state(newval)
nodejs
function set_state(newval)
php
function set_state($newval)
cpp
int set_state(Y_STATE_enum newval)
m
-(int) setState: (Y_STATE_enum) newval
pas
function set_state(newval: Integer): integer
vb
function set_state(ByVal newval As Integer) As Integer
cs
int set_state(int newval)
java
int set_state(int newval)
py
def set_state(newval)
cmd
YRelay target set_state newval

Parameters :

newvaleither Y_STATE_A or Y_STATE_B, according to the state of the relays (A for the idle position, B for the active position)

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→set_stateAtPowerOn()
relay→setStateAtPowerOn()
relay.set_stateAtPowerOn()relay.set_stateAtPowerOn()relay→set_stateAtPowerOn()relay→set_stateAtPowerOn()[relay setStateAtPowerOn: ]relay.set_stateAtPowerOn()relay.set_stateAtPowerOn()relay.set_stateAtPowerOn()relay.set_stateAtPowerOn()relay.set_stateAtPowerOn()YRelay set_stateAtPowerOn

Preset the state of the relays at device startup (A for the idle position, B for the active position, UNCHANGED for no modification).

js
function set_stateAtPowerOn(newval)
nodejs
function set_stateAtPowerOn(newval)
php
function set_stateAtPowerOn($newval)
cpp
int set_stateAtPowerOn(Y_STATEATPOWERON_enum newval)
m
-(int) setStateAtPowerOn: (Y_STATEATPOWERON_enum) newval
pas
function set_stateAtPowerOn(newval: Integer): integer
vb
function set_stateAtPowerOn(ByVal newval As Integer) As Integer
cs
int set_stateAtPowerOn(int newval)
java
int set_stateAtPowerOn(int newval)
py
def set_stateAtPowerOn(newval)
cmd
YRelay target set_stateAtPowerOn newval

Remember to call the matching module saveToFlash() method, otherwise this call will have no effect.

Parameters :

newvala value among Y_STATEATPOWERON_UNCHANGED, Y_STATEATPOWERON_A and Y_STATEATPOWERON_B

Returns :

YAPI_SUCCESS if the call succeeds.

On failure, throws an exception or returns a negative error code.

relay→set_userData()
relay→setUserData()
relay.set_userData()relay.set_userData()relay→set_userData()relay→set_userData()[relay setUserData: ]relay.set_userData()relay.set_userData()relay.set_userData()relay.set_userData()relay.set_userData()

Stores a user context provided as argument in the userData attribute of the function.

js
function set_userData(data)
nodejs
function set_userData(data)
php
function set_userData($data)
cpp
void set_userData(void* data)
m
-(void) setUserData: (void*) data
pas
procedure set_userData(data: Tobject)
vb
procedure set_userData(ByVal data As Object)
cs
void set_userData(object data)
java
void set_userData(Object data)
py
def set_userData(data)

This attribute is never touched by the API, and is at disposal of the caller to store a context.

Parameters :

dataany kind of object to be stored

relay→wait_async()relay.wait_async()relay.wait_async()

Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.

js
function wait_async(callback, context)
nodejs
function wait_async(callback, context)

The callback function can therefore freely issue synchronous or asynchronous commands, without risking to block the Javascript VM.

Parameters :

callbackcallback function that is invoked when all pending commands on the module are completed. The callback function receives two arguments: the caller-specific context object and the receiving function object.
contextcaller-specific object that is passed as-is to the callback function

Returns :

nothing.

21. Troubleshooting

21.1. Linux and USB

To work correctly under Linux, the the library needs to have write access to all the Yoctopuce USB peripherals. However, by default under Linux, USB privileges of the non-root users are limited to read access. To avoid having to run the VirtualHub as root, you need to create a new udev rule to authorize one or several users to have write access to the Yoctopuce peripherals.

To add a new udev rule to your installation, you must add a file with a name following the "##-arbitraryName.rules" format, in the "/etc/udev/rules.d" directory. When the system is starting, udev reads all the files with a ".rules" extension in this directory, respecting the alphabetical order (for example, the "51-custom.rules" file is interpreted AFTER the "50-udev-default.rules" file).

The "50-udev-default" file contains the system default udev rules. To modify the default behavior, you therefore need to create a file with a name that starts with a number larger than 50, that will override the system default rules. Note that to add a rule, you need a root access on the system.

In the udev_conf directory of the VirtualHub for Linux46 archive, there are two rule examples which you can use as a basis.

Example 1: 51-yoctopuce.rules

This rule provides all the users with read and write access to the Yoctopuce USB peripherals. Access rights for all other peripherals are not modified. If this scenario suits you, you only need to copy the "51-yoctopuce_all.rules" file into the "/etc/udev/rules.d" directory and to restart your system.

# udev rules to allow write access to all users # for Yoctopuce USB devices SUBSYSTEM=="usb", ATTR{idVendor}=="24e0", MODE="0666"

Example 2: 51-yoctopuce_group.rules

This rule authorizes the "yoctogroup" group to have read and write access to Yoctopuce USB peripherals. Access rights for all other peripherals are not modified. If this scenario suits you, you only need to copy the "51-yoctopuce_group.rules" file into the "/etc/udev/rules.d" directory and restart your system.

# udev rules to allow write access to all users of "yoctogroup" # for Yoctopuce USB devices SUBSYSTEM=="usb", ATTR{idVendor}=="24e0", MODE="0664", GROUP="yoctogroup"

21.2. ARM Platforms: HF and EL

There are two main flavors of executable on ARM: HF (Hard Float) binaries, and EL (EABI Little Endian) binaries. These two families are not compatible at all. The compatibility of a given ARM platform with of one of these two families depends on the hardware and on the OS build. ArmHL and ArmEL compatibility problems are quite difficult to detect. Most of the time, the OS itself is unable to make a difference between an HF and an EL executable and will return meaningless messages when you try to use the wrong type of binary.

All pre-compiled Yoctopuce binaries are provided in both formats, as two separate ArmHF et ArmEL executables. If you do not know what family your ARM platform belongs to, just try one executable from each family.

22. Characteristics

You can find below a summary of the main technical characteristics of your Yocto-MaxiRelay module.

Width58 mm
Length69 mm
Weight65 g
USB connectormicro-B
Channels8
Max switching current6 A
Max switching power1500 W
Max voltage250 V
USB consumption~350 mA
Supported Operating SystemsWindows, Linux (Intel + ARM), Mac OS X, Android
Driversno driver needed
API / SDK / Libraries (USB+TCP)C++, Objective-C, C#, VB .NET, Delphi, Python, Java/Android
API / SDK / Libraries (TCP only)Javascript, Node.js, PHP, Java
RoHSyes
USB Vendor ID0x24E0
USB Device ID0x0020
Suggested enclosureYoctoBox-MaxiRelay-Transp

23. Index

A
advertisedValue
API
B
beacon
C
CheckLogicalName
countdown
D
delayedPulse
delayedPulseTimer
describe
DisableExceptions
download
E
EnableExceptions
EnableUSBHost
F
FindModule
FindRelay
firmwareRelease
FirstModule
FirstRelay
FreeAPI
functionCount
functionId
functionName
functionValue
G
get_advertisedValue
get_beacon
get_countdown
get_errorMessage
get_errorType
get_firmwareRelease
get_friendlyName
get_functionDescriptor
get_functionId
get_hardwareId
get_icon2d
get_lastLogs
get_logicalName
get_luminosity
get_maxTimeOnStateA
get_maxTimeOnStateB
get_module
get_module_async
get_output
get_persistentSettings
get_productId
get_productName
get_productRelease
get_pulseTimer
get_rebootCountdown
get_serialNumber
get_state
get_stateAtPowerOn
get_upTime
get_usbBandwidth
get_usbCurrent
get_userData
GetAPIVersion
GetTickCount
H
HandleEvents
I
InitAPI
isOnline
isOnline_async
L
load
load_async
logicalName
luminosity
M
maxTimeOnStateA
maxTimeOnStateB
Module
N
nextModule
nextRelay
O
output
P
persistentSettings
PreregisterHub
productId
productName
productRelease
pulse
pulseTimer
R
reboot
rebootCountdown
RegisterDeviceArrivalCallback
RegisterDeviceRemovalCallback
RegisterHub
RegisterHubDiscoveryCallback
RegisterLogFunction
registerValueCallback
Relay
revertFromFlash
S
saveToFlash
SelectArchitecture
serialNumber
set_beacon
set_logicalName
set_luminosity
set_maxTimeOnStateA
set_maxTimeOnStateB
set_output
set_state
set_stateAtPowerOn
set_usbBandwidth
set_userData
SetDelegate
SetTimeout
Sleep
state
stateAtPowerOn
T
techspec
triggerFirmwareUpdate
U
UnregisterHub
UpdateDeviceList
UpdateDeviceList_async
upTime
usbBandwidth
usbCurrent
usbcurrent
W
wait_async
wiring
Y
YModule
YRelay


  1. support@yoctopuce.com
  2. The HID driver is the one that takes care of the mouse, the keyboard, etc.
  3. Although they existed for some time, Mini A connectors are not available anymore http://www.usb.org/developers/Deprecation_Announcement_052507.pdf
  4. short-short-short long-long-long short-short-short
  5. support@yoctopuce.com
  6. www.yoctopuce.com/EN/virtualhub.php
  7. The interface was tested on FireFox 3+, IE 6+, Safari, and Chrome. It does not work with Opera.
  8. www.yoctopuce.com/EN/virtualhub.php
  9. More information available in the virtual hub documentation
  10. Relay contact life, Application note, Tyco electronics, http://relays.te.com/appnotes/app_pdfs/13c3236.pdf
  11. www.yoctopuce.com/EN/virtualhub.php
  12. http://www.yoctopuce.com/EN/libraries.php
  13. If you want to recompile the command line API, you also need the C++ API.
  14. http://www.yoctopuce.com/EN/libraries.php
  15. http://www.yoctopuce.com/EN/virtualhub.php
  16. Actually, as soon as Opera implements support for the HTTP Access-Control-Allow-Origin header.
  17. www.yoctopuce.com/EN/libraries.php
  18. www.yoctopuce.com/EN/virtualhub.php
  19. If you do not have a text editor, use Notepad rather than Microsoft Word.
  20. A couple of free PHP servers: easyPHP for Windows, MAMP for Mac OS X.
  21. www.yoctopuce.com/EN/libraries.php
  22. www.yoctopuce.com/EN/virtualhub.php
  23. If you do not have a text editor, use Notepad rather than Microsoft Word.
  24. http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-cpp-express
  25. www.yoctopuce.com/EN/libraries.php
  26. www.yoctopuce.com/EN/libraries.php
  27. www.yoctopuce.com/EN/article/new-objective-c-library-for-mac-os-x
  28. http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-basic-express
  29. www.yoctopuce.com/EN/libraries.php
  30. The sources of this DLL are available in the C++ API
  31. Remember to change the filter of the selection window, otherwise the DLL will not show.
  32. http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-csharp-express
  33. www.yoctopuce.com/EN/libraries.php
  34. The sources of this DLL are available in the C++ API
  35. Remember to change the filter of the selection window, otherwise the DLL will not show.
  36. Actually, Borland provided free versions (for personal use) of Delphi 2006 and 2007. Look for them on the Internet, you may still be able to download them.
  37. Delphi libraries are regularly tested with Delphi 5 and Delphi XE2.
  38. www.yoctopuce.com/EN/libraries.php
  39. Use the Tools / Environment options menu.
  40. http://www.python.org/download/
  41. www.yoctopuce.com/EN/libraries.php
  42. www.yoctopuce.com/EN/libraries.php
  43. www.yoctopuce.com/EN/virtualhub.php
  44. www.yoctopuce.com/EN/libraries.php
  45. Yoctohubs are a plug and play way to add network connectivity to your Yoctopuce devices. more info on http://www.yoctopuce.com/EN/products/category/extensions-and-networking
  46. http://www.yoctopuce.com/FR/virtualhub.php
Yoctopuce, get your stuff connected.