ATtiny PWM switching regulator (buck converter) shower extractor fan control.
Channel: Nick Norton
Date: 22/02/2012

ATtiny45/85 or ATmega internally clocked at 8MHz
to do temperature sensing fan control.

This demonstration uses an ATtiny85 programmed using
the Arduino board and IDE to provide a PWM signal.

Configure your Arduino IDE and Arduino board
as an in circuit programmer using this guide:
http://hlt.media.mit.edu/?p=1229

You'll need to change your preferred AT microcontroller
to run internally at 8MHz.
You can do this in the Arduino IDE by selecting your board type in the
Tools - Board menu.
For example, choosing ATtiny85 (internal 8MHz clock) and then from
the tools menu again choose Burn Bootloader.

The code and more pictures of the project are available at:
http://nicknorton.net/?q=node/7