Monday, October 10, 2011

Hot plate PI controller - Part 1: The start

I want to make a hot plate controlled by a PI controller. The reasons are primarily to master the PI controller practically with the bonus of being able to control the boiling process when making home made beer.

Yesterday I boiled my first batch of wort and got the feeling of what it takes to control the temperature with several liters of wort (about 30 litres) on a small 1,5 kW old fashioned hot plate. The process was pretty slow, so it is absolutely possible to control it manually, but I want to set it at a specific temperature and let a home made controller do the rest of the job.

The parts I want to use for the project is:

  1. Controller: An old Arduino NT that I got lying around. This will be permanently used for brewing purposes in the future.
  2. Actuating element: A 1,5 kW hot plate of the old kind with built in on/off controller and stepless adjustment of power.
  3. Actuator: A 180 degrees adjustable Hitec HS-325HB RC servo for attaching to the power knob.
  4. Temperature sensor: A termistor type termometer that I want to reverse engineer and use the probe from.