MightyOhm.com

For me it ran 5 days continously. Then I got more and more bursts of faulty readings (way too high) from the GC. The voltage of the batteries had dropped to 2.5V by then, which is propably a bit too far off. (E.g. the datasheet for the Atmel mentions VCC 2.7V min.)

After fixing the short-circuit, the remaining step would be to connect J6-1 to any 3.3V pin from the Raspberry Pi (1, 17) to provide power to the Geiger Counter. Since the GC only needs ~8mA you could even connect it to a GPIO pin (they can handle up to 16mA) instead of 3.3V, e.g. like this: Raspber...