Modification to my Ender 3 3D Printer's Raspberry Pi b+ controller.
Circuit created from this post https://hackernoon.com/how-to-control-a-fan-to-cool-the-cpu-of-your-raspberrypi-3313b6e7f92c
I added a flyback diode for safety though.
Fan: Ender 3's 24V Stock part cooling fan, I replaced it with dual 12V 5015's so I had it laying around.
Diode: I used a 1N4007, but you can use any of the 1N400X line.
Transistor: S8050
