AVR ATtiny Fan controller
http://blog.zakkemble.co.uk/avr-microcontroller-based-pwm-fan-controllers/

Schematics, PCB layouts and code for making a basic PWM fan controller using an ATtiny5, 10, 25, 45 or 85 microcontroller.

The .hex files in ./firmware/attiny25_45_85/hex/ are compiled for ATtiny25, but should also work with ATtiny45 & 85
The .hex file in ./firmware/attiny5_10/hex/ is compiled for ATtiny10, but should also work with ATtiny5
Fuse settings are in ./firmware/<Your uC>/fanController/config.h

Zak Kemble
contact@zakkemble.co.uk