I am interested in setting up a controller which can modulate the output of 2 hotpads based on input from an infrared thermometer. The hotpads have their own dials, but I am considering controlling them by voltage instead. So my question is, what is the simplest method for modulating voltage (or rotating dials) based on temperature? One problem in particular that I am unsure about is how to account for the gradual propagation of heat through my system, since I am heating a large (2' diameter, 1" thick) rotating aluminum disk. I have a laptop at my disposal, and minimal funding.
I would prefer to avoid wiring my own sensors, so any recommendations you have on how to achieve this would be great. I could handle a breadboard at best with my experience, and I have only an introductory level understanding of electromagnetism... But I can code in C, Java, and Matlab, and I have experience assembling PCs, so I am hoping this is within my abilities.