How to Build a Cheap Thermal Camera with a Raspberry Pi

They can be quite expensive, but thermal cameras come in handy for a lot of projects. You could, for instance, use a thermal camera to see if your 3D printer’s heated bed has any cold spots. Home owners can check their house’s walls to see if the insulation has any thermal leaks. You can even use one to pretend you’re the Predator. Walker2000 wanted to be able check his insulation, and so he came up with an inexpensive Raspberry Pi thermal camera.

This project relies on an affordable MLX90640 thermal camera module that was recently released in the Chinese market and that’s now available through websites like Banggood.com. It has a fairly low resolution — just 32x24 pixels — but it’s relatively inexpensive and comes in a small package. It’s usually populated on a separate board that includes an STM32F103 microcontroller. Communication is handled either directly via I2C to the MLX90640, or through an RS-232 serial interface with the STM32F103 microcontroller.

Walker2000 decided to use the latter option to connect the board to a Raspberry Pi Zero W. The manufacturer of the camera module does provide software to use, but it’s completely in Chinese. For that reason, Walker2000 decided to setup a script that polls the camera and then creates a visualization using OpenCV. The Raspberry Pi runs headless with a VNC server, that way he is able to connect to the server with his smartphone to see the output from the camera. It may not have the resolution of a high-end thermal camera, but at less than $100 to build, it’s much less expensive.