dyqik
Well-Known Member
You can easily control the speed of a 12/24V DC pump from a microcontroller output that can drive a high frequency PWM output. All you need is a FET transistor. Use the microcontroller's pin to drive the gate of the FET. I do this with an Arduino. Disclaimer, I haven't done this on a Pi and I have no idea if the craftbeerpi SW will support high frequency PWM outputs.
There Pi only has one PWM capable output, and I don't know how high in frequency it can go. There are PWM output add on boards though.