The project illustrates the control of a PC fan speed and using an Arduino microcontroller to read a LM35 temperature sensor. The use of an optocoupler is covered along with Pulse Width Modulation ...
I've got a storeroom in a garage that has some stuff in it that is a little more temperature sensitive, and has more variability than I'd like (it also has some equipment that generates a bit of heat, ...
When it comes to performance, there's a world of difference between the Raspberry Pi and Arduino. The former, after all, is technically a fully functional computer that can run games, word processors, ...