My initial proofing box was an important part of getting consistent results when baking bread but it stopped working rather mysteriously while I was out of town in 2018. That version was built on a Raspberry Pi, had an integrated webcam, and recorded timelapse movies of bread rising. As cool as all that was, it was a giant pain to manage and troubleshoot. Since it was running linux much of the work of maintaining it was effectively system administration, which is not a task I enjoy.
So when it came time to rebuild I decided to go with a much simpler design. This new version is built around an Adafruit Feather M0 Bluefruit LE that I happened to already have. It lacks any kind of network awareness (I’m not using the bluetooth at all) but it does have a bright OLED display and physical controls, making it perfect for my needs.
The electronics are modular, built around the Feather spec, so that the display, power electronics, and microcontroller can each simply be unplugged and removed for maintenance or replacement. The power electronics module is responsible for providing 5V to the microcontroller and switching 12V to the heaters in response to a PWM signal from the microcontroller.
I let this project burn in for several months before finally mounting everything into a project box. Having real buttons and a power switch feels like a giant luxury after dealing with the tiny buttons on the OLED and pulling the plug to turn it off.
Hopefully this revision lasts a good long time and I won’t need to update it until I finally decide to build a proper box (if I ever do - foam has its advantages).