What is it?

Breakout board for Melexis MLX90621 16 x 4 IR imaging array with 120 x 25 degrees FoV and maximum temperature range up to 1100 C.

This is the populated pcb with everything you need to make use of the MLX90621 IR Array except the array itself. You may purchase the MLX90621 from Mouser or Digikey. It is an expensive part, so I am offering only the populated pcb with through holes for mounting the MLX90621, 4K7 pullups on the SDA and SCL pin pads, and an NCP161AMX25 450 mA, 2.5 V LDO with bypass capacitors on the VDD input. Now the Melexis MLX90621 is a low current (< 9 mA) device but the NCP161AMX series offers ultra-low noise figure and quiescent current (18 microAmp), so this is a good choice to power the array. A simple diode can also be used but this is not a 3.3V-tolerant sensor, 3.0 V is the maximum voltage so some kind of step down is required from standard 3V3 and I have chosen a low noise, high-accuracy LDO here.

The IR array itself offers 4 x 16 pixels of absolute temperature with high accuracy (~1 degree C) and with a choice of three fields of view: 40 degrees, 60 degrees, and 120 degrees. One can trade off resolution (15- to 18-bit) for temperature full range (up to 1100 C in the 120-degree FoV model). The MLX90621 offers sample rates from 0.5 Hz to 512 Hz. All configuration controls are accomplished via simple I2C register writes.

Why did you make it?

I love sensors and this one offers thermal video capability at a fraction of the cost of a FLIR system. Yes, it is only 4 x 16 pixels but this is enough to distinguish two objects at different temperatures sitting next to each other, to map the temperature distribution of an object with high accuracy, and to measure time evolution of an object's temperature field as it warms or cools. Running the sensor at 30 or 60 Hz allows video of the temperature distribution to be recorded and, here is the advantage of only 64 pixels, the data can be stored on a small EEPROM or SPI flash, or even streamed over BLE in real time.

What makes it special?

This is a super-small breakout for the MLX90621 (MLX90621 not included!) but with the pullups and LDO required to make the MLX90621 work. Just solder your MLX90621 onto the board, connect 3V3/GND and SDA/SCL and use the sketch I wrote to start streaming a 4 x 16 array of temperatures to your serial monitor or TFT display.

Order the pcb from OSH Park and make your own or order the assembled and tested pcb from me (and an MLX90621 from Mouser or Digikey) and see what you can do with an IR temperature video camera!