Control a Raspberry Pi fan based on temperature. Four Possible methods:
You can purchase the tiny EZ Fan2 control board on Tindie: https://www.tindie.com/products/jeremycook/ez-fan2-tiny-raspberry-pi-fan-controller/
Note that the EZ Fan2 can be used for any small load up to a .6A limit (may need to de-rate in some situations) and fetures a flyback diode to help
allieviate voltage spikes.
Further fan control/development info: https://www.youtube.com/watch?v=F1FQojoaNS8
Control fan with Raspberry Pi OS: https://www.youtube.com/watch?v=AdjU_AVcZTA
Control 12V fan (or other load) with the EZ Fan2: https://www.youtube.com/watch?v=bBBTj0RP7F8
Items used in video:
ICE Tower: https://amzn.to/2N95qrn [Amazon]
2N2222 Transistor: https://amzn.to/2AK2vTy [Amazon]
Heat Shrink: https://amzn.to/2C8qf3Z [Amazon]
*note that Amazon links are affiliate, meaning I get a percentage of sales