One of the problems I've had with my fermentation, is fluctuating temperatures in the area where I ferment my beer. I put in a small electric heater, but this has led to a high electric bill and a continuing issue, as the room is not well insulated.
A few months back, I picked up a couple of heat belts which I can wrap around my fermenters, but once plugged in, they give constant heat, and so need to be connected to a thermostat. I solved this problem by building some small controllers. The main body of the controller is an old HP power supply from the PCs which were thrown away at work. This was a bonus, as there were a lot of wires in the power supply which I could reuse, as well as the 220V plug. I stripped out the components and riveted a new plate of metal on the front, so I would have a place to mount the components. I then put in an SSR (solid state relay), a power plug (for the heating belt), a stereo jack (for the thermometer), a PID (to control the temperature), a light (to indicate when the heating belt is active), and a power switch. Now I am able to set the PID to 20C, tape the thermometer to the side and wrap the heat belt around the fermenter, and keep the fermentation temperature from dropping a making the yeast inactive.
controller
