Winter has arrived, and so I had to check the thermal insulation of my out of town residence dacha. And it just turned out a famous Chinese marketplace started to sell cheap thermal camera modules. So I decided to DIY it up and build a rather exotic and useful thing — a heat visor for the home. Why not? Especially since I had a Raspberry Pi lying around anyway… The result is down below.
MLX90640. What is it?
This is a thermal camera matrix with an onboard microcontroller, made by an unknown (to me) company called Melexis. The matrix is 32x24 pixels, which isn’t a lot, but after interpolation it’s enough to notice general trends.
The sensor comes in two versions, the only difference being the case and the camera’s FoV. The more grounded A model observes the world with 110 degrees horizontally and 75 vertically. The B model has 55 and 37.5 degrees respectively. The case has four outputs — two for power and two for talking to a controller device via I2C. The datasheet can be found here.
Whats GY-MCU90640, then?
Our Chinese fellows also ship the MLX90640 chip with another microcontroller on board (STM32F103), probably for easier matrix control. The whole unit is called GY-MCU90640, and it costed me around 5000 RUB (roughly $80) in December 2018. It looks like this:”