DIY Geiger Counter: When the Big One Drops, You Will Be Ready [Mr Fission]
When the world finally goes all to hell and the missiles start flying, a Geiger counter will be a handy tool for anyone who survives the blast. Be prepared by building your own Mr. Fission radar detector. The device works with a standard Geiger tube, a high voltage power supply, and a design based around a Motorola MC68HC908KX8 microcontroller.
If you are interested in building one of these yourself, the designer is in the process of developing a simpler, cheaper version complete with detailed information and schematics. Until then, you can hit him up for some info on the project in the following link [N1VG via Hack a Day via Make]
Source: Gizmodo: DIY