PiGI - A Raspberry Pi Geiger-Mueller Interface

The PiGI is built as a ready-to-go drop-in module for the Raspberry Pi to transform it into a versatile geiger counter to measure/monitor radioactivity. It will generate the required high voltage the counting tubes need to operate and it will safely invert the counting impulses to a falling edge, detectable by a GPIO Pin on the PI.

But it’s also designed in such a universal way in order to be very hackable. Basically it can be connected to any processing system that can detect falling edges like:

Arduino
ATMega
PIC
Other embedded Linux ARM/MIPS systems with GPIO Inputs (GNUBLIN, Netus G20 etc.)”

Link