The Yocto-Light device is an USB ambiant light sensor (lux meter) which will allow you to you measure ambient light up to 65000 lux. Measurements can be directly read via USB or stored on the device internal flash for later retrieval when connected again by USB.
This module can be used in conjunction with a directional light source to create a light barrier. Be aware however that measures will be averaged on a 0.25 second period, so it is not appropriate to detect very short events. To detect light with a precise timing but without calibrated intensity measurement, it is more appropriate to use a Yocto-Knob with a phototransistor.
This circuit has been designed so that the sensor itself can be moved further away from the USB by a few meters: simply split the board into two parts and solder a 4-wire cable on the designated pads.
This device can be connected directly to an Ethernet network using a YoctoHub-Ethernet, to a WiFi network using a YoctoHub-Wireless-g, it can even be connected to a GSM network thanks to the YoctoHub-GSM.
USB cables and enclosures to be ordered separately.
The Yocto-Light is now fully supported by Valarm, available for Android devices in the Google Play store: https://play.google.com/store/apps/details?id=net.valarm.android.pro
Valarm is the Versatile Asset Locator And Remote Monitor. You can use it to track almost anything via GPS, and to monitor almost any environment via sensors.
Valarm responds to configurable triggers: limits set by you on each sensor (also currently supported are the Yocto-Meteo and Yocto-Temperature, more on the way!). Possible responses include:
- Send SMS/text msg
- Send email
- Post to the Valarm website
- Play an alarm sound
- Take a photo
- Record audio
In other words, you can configure Valarm to send a text, email, or post to your account on tools.valarm.net, when any sensor is triggered by your settings. With the Yocto-Light and Valarm you will know when the lights go out on your aquarium or hydroponics rig or whatever else your scenario is! See http://www.valarm.net or more info and/or email us at firstname.lastname@example.org
I was wondering whether it was feasible for Yocto light to pick up the turbidity of water? Is it sensitive enough? I was thinking of setting up a system where the Yocto light could be put into a drain with an LED set a certain distance away. the cloudier the water, the less light reaching the Yocto light. Clearly I'd have to waterproof everything but could this work?
@libby Nice idea. Yes, I am pretty confident it would work, since turbidity is defined in terms of percentage of deflected light. You would simply have to pick a source of light and measuring distance that provides no more than 65000 lux when no light is deflected at all, and then you should be able to deduce the turbidity.
Is there a min/max operating temp specification? I see that the main components are industrial rated.
The min/max temperature range is -15/70░C (the fragilest component is the light sensor).
I got my yoctolight and it works as expected! I did not see info at Osrams pages or anywhere else if it survives direct sunlight. I believe that direct sunlight is >65klx and it may also imply 70C or more I guess.
@molkko: the 65K limit is more related to the digital encoding used by the sensor to report its value, and for the specified accuracy. There is no maximum light listed in the absolute maximum ratings, only temperature. Officially, the sensor can be stored up to 85░C, so even temperatures between 70░C and 85░C should not damage the chip normally. Actually OSRAM explicitely list among the sensor applications "Sunlight sensor" in the front page of the datasheet.
I need the light sensor to be about 6m (cable length) from the computer. The product information says the sensor can be extended "a few meters". What is the maximum length of (a) the USB cable and (b) the sensor extension cable?
As a general rule, it is best to keep USB cables not longer than 1m. You can however find so-called "active USB cables" up to 5m which actually embed an single-port USB hub. In many cases, long cables may cause voltage drop issues, but if you just want to put a Yocto-Light at the end, you will not have any issue since the Yocto-Volt only consumes very little current.
So you have the choice: either use one of this "active USB cable" of 5m, or move away the sensor part. We have successfully tested a sensor which was 100m away from the base device (using UTP cable).