HiLetgo GY-906 MLX90614ESF Non-Contact Infrared Temperature Sensor Module IIC I2C Serial for Arduino

I bought one of these to add to a mobile weather instrument to record road surface temps. I drilled a hole in a small project case for the lens, attached neodymium magnets to the top of the case, and when I want to collect data I just slap the case under the car and go. So far I’ve had no problems, and the temperature values are within 2 degrees of manual comparisons using a handheld IR thermometer. The programming is simple when using the Adafruit library.

I'm working on a personal project to build a non-contact thermometer as a concrete project to help teach me PIC programming, I2C, PCB design, and enclosure design for 3D printing. This breakout board has been convenient for prototyping on a breadboard (see picture). Also the price of the board rival the quantity one price for the sensor alone, so it's a good deal. Some things to note. The MLX90614 sensor comes in different sub-models. This board uses the BAA sub-model, which is what I wanted. It's not strictly medical accuracy--for that you need the more expensive DCI sub-model--but IMHO is good enough to screen for high fevers. I'm not allowed to put a non-Amazon URL here, so you'll have to google for the Melexis datasheet on the MLX90614; you'll have to read the datasheet to understand how to control the sensor. For what it's worth, I'm controlling the sensor in my application from a PIC16LF19156 8-bit microcontroller with a built-in I2C/SMBus interface. The board has a 3.3V regulator on it, but I've run it at 2.8V without modification. According to the datasheet, the sensor needs at least 2.6V to operate. The board contains pull-up resistors for SCL/SDA and a filter capacitor across power/ground. This board has behaved just as I expected and has been very convenient. I'm glad I bought it.

There are a few things to consider here - this model comes in different packages, different voltages etc. and this seller doesn't differentiate. This seems to be a 5V module with a regular to 3.3v - which means those of us that uses 3.3V devices are "not getting the full bang for the buck". I'll remove the regulator and give the unit the voltage it requires, and hopefully it solves what I'm seeing. I have this unit working - took a bit of tweaking though. There are several Arduino libraries that covers this unit, but the actual coding isn't too complex if you had to make it from scratch; I ended up using the DFRobot_MLX90614 library since it uses the native Wire interface and doesn't mess with everything else I have (hint - careful with Adafruit) and ESPHOME is a relatively simple setup with this library. HOWEVER, every initial reading of either ambient or object temperature fails. All subsequent reads work just fine, so in the end that was a simple fix. I suspect this is due to using 3.3V on the VIN pin, so I'm hoping this goes away when that's fixed. What I'm not so happy about is the temperature difference. Even sitting just a foot away from the sensor it barely measures above room temperature (about 2 degrees centigrade). I almost have to put my hand over the sensor (not touching) to see it go up significantly. So the spectrum it covers seems extremely wide. If the device keeps the sensor values relatively constant, I can still use any temperature difference to detect a human presence but that's for more testing. You should know what you're getting into - it's definitely not on the cheaper side when coming to sensor objects for basic Arduino stuff.

It has a pretty wide angle so you can't get too far away from a point source. First time using one of these, I connected it to an esp8266 and it works. I've had good experiences with the HiLetgo branding.

Great working thermopile type sensor. The adafruit library makes accessing this a breeze, up and running in less than a minute. It's nice that it also gives access to the onboard thermistor for ambient (part) temperature sensing in addition to the object temperature via the thermopile. HiLetgo GY-906 MLX90614ESF Non-contact Infrared Temperature Sensor Module IIC I2C Serial for Arduino

Have made a few sensors with these

I found this thermal sensor is simple to use with the Arduino and its IDE when using the Adafruit MLX90614 library to communicate. So far I have not run into any issues while using this sensor and the board looks quality built. To help others I included a screen shot of the Arduino IDE settings, wiring diagram, and the demo Arduino code sketch I used with this sensor.

Sensor worked as advertised, not sure why you can buy a module cheaper than the sensor itself but that for a different review. I do highly recommend going to Adafruit website for support code if working on Arduino as the code they have available works well and give you a great starting place for developing your own.