They used an Arduino to control the temperature and a motor shield to power the peltier plate. It kind of worked but they discovered it was difficult to assess the physical state of the chocolate.

New Book Release The new book, PID-Based Practical Digital Control with Raspberry Pi and Arduino Uno , is about using the Raspberry Pi 4 and Arduino Uno in PID-based automatic control applications.

But along the way he took the time to explain PID control and the choices he made during development. We see a lot of PID controllers around here, like this router based espresso machine add-on.