One application of thermal imaging which has been experiencing a surge in recent times is the application of thermal imaging in the detection of faults in circuits. While this has proven a very interesting and reliable way for evaluating Circuit boards before committing to mass production, the cost of the standalone solutions and even the smartphone adapter based thermal cameras and accompanying app has been a challenge for most users as they are usually expensive and not open source. To solve this problem and democratize access to the thermal camera for use in Circuit evaluation, TheMarpe, has developed an Open-source alternative which is rightly called the Open Thermal Camera.
The Open thermal Camera uses the SmartPhone adapter model as it comprises of a thermal camera and a mobile app. The thermal camera is designed to plug into the MicroUSB port on the phone, with a new release of the thermal camera coming with a USB-C option to support phones based on it. With the camera connected, the app is then launched and users can interact with it and evaluate their circuits.
The Open Thermal camera comes in an incredibly small form factor, with all the electronics bumped into an incredibly small 26 x 20 mm PCB. Its design is based on the MLX90640 sensor which is a far-infrared camera with an array of 768 (32×24) thermal sensors that can detect temperatures from -40 to 300°C with approximately 1°C accuracy and up to 64FPS. The camera outputs still images with a resolution of 32 x 24 pixels, and while that might sound quite small and a bit lower than the commercial smartphone adapters, it has been proven to be adequate enough tasks like detecting faults and characterizing a PCB’s thermal performance.
Comparing with the commercial options which fall between $200 and $300 price tags, a look at the BOM of the thermal camera reveals an estimate of only $54 as the cost of its active components with $50 of that cost being the cost of the MLX90640 itself.
Currently, only an Android application based version is available, but according to comments by TheMarpe, there may be plans to support development boards like the Raspberry Pi and other SBCs or a move towards a standalone version.