This week, we present the newest module in the range of Yoctopuce temperature sensors: the Yocto-MaxiThermistor. The ideal product if you need to measure temperature at several locations.
The Yocto-MaxiThermistor is a double-width module with six inputs to which you can connect the thermistors of your choice.
Thermistors are resistances with a resistivity that changes significantly depending on the temperature. There are two main families of thermistors: NTC and PTC. The Yocto-MaxiThermistor can manage both. Each thermistor model has its own characteristics, usually described in its technical specifications. These characteristics are presented either as a temperature/resistance table, or as a β coefficient and a reference value. The Yocto-MaxiThermistor works with the two models.
The Yocto-MaxiThermistor is an insulated module: the measuring part is electrically insulated from the USB bus. You can thus measure the temperature of objects even if their electric potential is different than that of the controlling computer.
For you to easily test the Yocto-MaxiThermistor, it is delivered with six tiny Murata NTC NXFT15XH103 thermistors. You can find their characteristics in the Yocto-MaxiThermistor documentation. Note that these thermistors are mounted on wires that are 10cm long. You might need to extend them.
The Yocto-MaxiThermistor is sold with 6 NTC thermistors
The Yocto-Thermistor-C is a variant of the Yocto-MaxiThermistor. Both modules are strictly identical with the exception of the connector. While the Yocto-MaxiThermistor offers six contact pairs to connect the 6 thermistors, the Yocto-Thermistor-C offers six single contacts and a common contact. This enables you to use wires with a larger section.
The Yocto-Thermistor-C, note the different connector
Thermistors are far from being a technology as accurate as PT100. In particular, for a same model, each thermistor is slightly different and the length of the connecting wire may have a slight influence. If you use a thermistor without calibrating it first, fully trusting the parameters provided in the specifications, accuracy depends mostly of the thermistor model, but even with a good thermistor, don't expect an absolute accuracy better than 0.5 degree, 1%. However, if you carefully calibrate each input to specifically adapt it to the thermistor connected to it, you can hope for an accuracy of 0.1 degree.
The Yocto-MaxiThermistor allows you to easily measure temperature in six different locations. In terms of cost per measuring point, it's clearly the cheapest of the Yoctopuce range, all of it in a 5 by 6 centimeter module.