Member Since: February 19, 2012
Country: United States
I wrote a version of the Geiger Counter firmware that uses the Arduino/Wiring libraries and the TimerOne library to create code that is more readable and easy to understand for beginners. The sketch can be found here.
Uploading it to the counter can be a bit difficult, but here is the way I recommend:
Run the following avrdude command, replacing /path/to/hex/file.hex with the location that you noted earlier, and /dev/deviceentry with whatever /dev/tty.usb* entry your programmer shows up as.
avrdude -c avrispmkii -p m328p -vvv -e -P /dev/tty.usbmodem621 \ -U flash:w:/path/to/hex/file.hex -U lock:w:0x0F:m
Hopefully that works for you. Good luck!