I disassembled an AMD CPU Wraith Cooler, meaning, I took the fan off of the heatsink, because I want to attach the fan on top of a Raspberry Pi that I'm using as a router. The Pi runs quite hot because it transmits several hundred megabytes per second, non stop, and I want to give it some cooling. (It already has its own heatsinks on its various chips inside the chassi and I don't want to use the little shitty Okdo fan, because it's loud.)
Is there any smart solution to how I could power this 4-pin fan? It needs 12V DC.
This is the Pi with its chassi.
And I'm considering something barbaric like this.
~~Are there perhaps conveniently positioned GPIO pins on the Pi that the 4-pin connector could just slide on to and just work?~~ Never mind this. The Pi 4 that I'm using can only output 5V:
Or would I need to cut off the 4-pin connector to expose the individual wires and attach them to a 12V DC adapter?
Or any other genuis solutions? :)
The pot is if you want to control the speed manually. The transistor if you want to control it from the pi (from the temperature for example).
If you want a potentiometer, there are two ways I think :
Have the potentiometer plugged to the pi ADC input, and in software regulate the pwm output to the transistor based on the signal coming from the pot.
Another way is to have the potentiometer in series with the fan and only control it from the pot. I've never built any circuit like this so there may be consideration to be put into the max current the pot can handle, but I guess for a small fan it could be okay.
In both cases you'll need a 12v source. Either a 12v power supply, or a DC step up from 5v (from the 5v power supply (maybe the same as the pi), not from a pin on the raspberry as it can't draw much current). In both cases, the grounds should be tied together so they all see the same voltage in reference to ground.
I can help you further if you want, but don't hesitate to ask a LLM for it as they can be quite good now for such circuits, and can in theory explain concepts you don't yet understand.