PWM Fan Controller for heat exchanger with timed defrost cycle
I believe that an Arduino Uno is probably the most &quot;user-friendly&quot; microcontroller out there. They are quite cheap, can connect to your computer via USB, and all they need to be programmed is the Arduino IDE (free download from arduino.cc). Another plus is that they have a huge forum and lots of documentation (forum at forum.arduino.cc). They can be set up in minutes and sound perfect for your application because they have more than 4 PWM-capabile pins.
Hope this helps and have a great day!