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 ...

This was achieved using an Arduino Mega 2650 and ... a saucepan it was configured as a PID controller, but the real vat proved to have a much greater thermal inertia so a simpler bang-bang home ...

[Tim] uses a toaster oven he paid $21 for, but anything with a suitable thermal mass will do ... interface (for the all-important PID control), LiPo battery charging, a buzzer for alerting ...