To implement a PID controller in an Arduino sketch, five parameters must be known: proportional, integral and derivative constants, input value and set point value. Well, let’s start with a crude demo ...

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.

[Matt] wanted to have more control over his meat smoker so he built this advanced PID smoker controller. It uses the solid state relay seen in the bottom-right of this image to switch the smoker&#8… ...