This was a great demo that Jeff Keyzer, aka MightyOhm, had going at his booth in the Maker Shed at the Maker Faire Bay Area. He had five or so of his geiger counter kits hooked up to an Arduino and as each geiger counter sensed radiation, it played a note.
Geiger Counter Kit – Radiation Sensor. Detect particles and/or make a cool random number generator with this handsome Geiger counter kit. This easy-to-make pack of parts turns a simple Geiger-Muller tube (included) into a portable blink, beeping radiation detector. You can also connect an FTDI friend to the header, to get serial output for datalogging on your computer.
We put this kit together in a couple of hours and hand lots of fun bringing it around and listening for ticking sounds near our smoke detectors, bananas, countertops, Brazil nuts, chunks of Uranium, etc. It includes all components (PCB, tube, & parts) but you will need basic soldering tools and two AAA batteries to complete it.
Best of all, it’s 100% Open Source Hardware!