It was pointed out to us that we didn't have an infrared temperature sensor in our module range. Not to worry, this week we present our brand new Yocto-Temperature-IR. Follow the guide.
The Yocto-Temperature-IR is a classic single-width Yoctopuce module, it is 51mm long, it is based on the MELEXIS MLX90614-DCA infrared sensor, and it can measure temperatures from -70° to 380°C. The DCx is the most accurate version of the MLX90614 range, its accuracy varies between ±0.2°C and ±4°C, depending on the temperature of the object to be measured and the surrounding temperature. You can find a graph in the documentation showing all the possible combinations.
The brand new Yocto-Temperature-IR
A multi-sensor module
Like many Yoctopuce sensors, the Yocto-Temperature-IR is divisible: you can split it into two parts to have on the one hand the USB part, and on the other hand the sensor part. You then only need to rewire the whole and to thus obtain a remote sensor easy to fit in cramped spaces.
The Yocto-Temperature-IR is divisible
But it doesn't stop here, the Yocto-Temperature-IR has an additional trick up its sleeve. You can connect additional sensors: the module can manage up to 10 MLX90614 sensors, you only need to wire them in a bus. Naturally, some software tweaking is necessary to configure the whole, but everything is explained in details in the documentation.
The Yocto-Temperature-IR can manage several MLX90614 sensors
However, Yoctopuce doesn't intend to provide these additional sensors. You have the choice between:
- Either vampirizing some Yocto-Temperature-IR to recover the sensors, but this is going to be very expensive
- Or buying some "MLX90614 Breakout Boards" on the Internet. Note, most of these boards are sold with cheap versions of the MLX90614, less accurate than the DCx range. But nothing prevents you from desoldering the sensor to replace it with another one
- Or even building them yourself: the circuit, which is described in the documentation, is quite trivial. There is only a sensor and a capacitor
How does it work?
The Yocto-Temperature-IR works by quantifying the infrared emissions which reach the sensor, in other words, it returns the average temperature of everything in its field of vision. It is therefore important to understand that to measure accurately the temperature of an object, the said object must take up the sensor whole field of vision. The field of vision of the MLX90614-DCA is of 90°, which is rather large. Consequently, the smaller or the thinner the object to be measured, the closer the sensor must be.
The object to be measured must take up the whole field of vision because the sensor averages what it sees
We could summarized this by saying that the Yocto-Temperature-IR is a thermal camera with a resolution of 1x1 pixel.
Variants
We decided to base the Yocto-Temperature-IR on the DCA variant of the MLX90614, because it is the most accurate and the most common of the DCx variants. However, if you want a Yocto-Temperature-IR with another variant of the MLX90614, for example to have a narrower angle of vision, contact us, it shouldn't be a big issue. However, as we don't intend to have all the variants of the MLX90614 in stock, expect a different price and a different delay.
Conclusion
The Yocto-Temperature-IR completes the range of Yoctopuce temperature sensors. Its first function is naturally to measure temperatures without contact, but given its sensitivity in the range corresponding to body temperature, we think that one could use it as a presence detector. We must perform a few experiments, and if it works, we'll probably write another post on the topic.
