[Harvs] hacked a cheap PID controller he found on eBay to improve ... and designed a replacement PCB to interface to the display and power supply. The new PCB is based around a Cypress PsoC ...

To reduce the temperature swing, [Rhys] decided to add a PID control loop, and on the way, an OLED display, too. He designed a little shield for the Arduino Nano, that interfaces with the present ...