GY-906 MLX90614 Non IR Infrared Temperature Sensor Module IIC I2C Serial for Arduino

These temperature sensors were a bit difficult at times to make sure the data and clock lines were clean, but once the were directly soldered to our custom PCB they seem to work as expected. I wouldn't expect them to give super accurate body temperature readings, but they are a good enough proof of concept.

I will update this review after I get it up and running. This preliminary review is to let potential buyers know what particular MLX90614 part this is. I got a MLX90614BAA (see photo). It is 3V part (1.3 to 2 mA draw) with a 90° field of view. The operating voltage range is 2.6V to 3.6V with 5V being an over voltage. Do *not* attempt to power this device with 5V. The seller ("Teyleten Robot-US") answered a question here about the supply voltage, saying "3-5V". The seller gave a very bad answer. Unless, I suppose, the seller's objective is to get you to burn out the part and then have to buy another.The field of view is important. This sensor will read an average temperature over the field of view. If the thing you are trying to measure does not fill the FOV (±45°), then you will be measuring the temperature of it averaged with the things around it. Carefully consider the placement of the sensor and its distance from the object.Update: Plugged it in to my Raspberry Pi 2, and it worked like a charm. I connected it to pins 1, 3, 5, and 6, which are 3.3V, I2C data, I2C clock, and ground respectively. Then using the adafruit_mlx90614 module in Python, I was able to read the ambient and target temperatures.It worked for a few days, and then the part failed! It just up and died for no apparent reason, getting hot and taking over the I2C bus. I returned it to Amazon and got a new one the next day. That one has been working fine.I have found that even when the object fully fills the advertised field of view, the temperature can still vary with distance. I am doing A/B testing and not too concerned about the absolute reading. However if you need absolute temperature, I recommend calibrating with a contact probe, so that you know what your readings from this sensor actually mean.

This until is nice to have as it incorporates all the require attenuators needed to make the device read from the I2C bus. Works well at 3.3V without a problem at all. This board makes the use of the MLX90614 sensor easy. Others have discussed issues with the MLX90614 itself as far as distance calculations, but that's not the fault of the board maker.

This sensor does not give accurate or consistent readings at all. Reading from a surface of a known temperature (77F using another contact sensor) this supposedly "non-contact" sensor had readings across a scale of as much as 30 degrees depending on distance from surface (0 to 2 inches) There is no datasheet. The link provided by the seller does not work. Placing a tube over the sensor does not improve the reading as some people will claim. Complete waste of money.

The sensor seems to be reasonably accurate (within 3 degrees of other thermometers i have laying around).Interesting note: the read temp changes greatly with the distance of the object from the sensor. I am still trying to figure out the specifics of the temperature measurement from the datasheet.The arduino code to read the sensor over i2c is as following:Wire.beginTransmission(0x5A);Wire.write(0x07); // read ram address 7(Temp object 1)Wire.endTransmission(false);//The SMBus communication will only respond with 3 bytes: data low, data high, and PEC (is CRC-8)Wire.requestFrom(0x5A, 3,true); // request 3 bytes from slave deviceunsigned int r = Wire.read(); // receive a byte as characterr |= (Wire.read()<<8);float k = r*0.02; //temp in kelvinfloat c = k-273.15;float f = (9*c/5)+32; //fahrenheitSerial.print(f); // print the characterSerial.print(' ');c = Wire.read();Serial.println();

It seems to work, in so far as reporting believable temperatures and reporting and setting emissivity, using an arduino-like platform as the host and the adafruit library for the mlx90614. It is convenient in that the circuit includes the pull-up resistors. No attempt so far to check accuracy.

Hooked it up to my Teensy, followed a YT video (by Saravanan AL), ran first time, reported as expected. One simple imperative statement... " mlx.readObjectTempF()". Thats it!

See Flagstone78’s review where he posted some code for the unit. Using a combination of this and some other stuff I found online I was able to get it to work for what I needed. The readings are a bit finicky and must be paired with a distance sensor in order to get accurate reading, because moving the device slightly from the object being measured will result in a wide temperature range. Also it is impossible to know, without testing, from which distance you need to measure at to get the correct temperature of the object, so some testing and experimentation with objects of a know temperature are needed to figure that out.