I have been using these little guys:
http://www.pjrc.com/teensy/index.html
Great boards, can be programmed in the Arduino environment or in standard Atmel C. Really cheap and tiny. Has real USB not a USB - TTL Serial converter and will show up as USB HID if you want.
Teensy
Forum rules
This is for things you've managed to miniaturize to the point of slipping into a pocket easily.
This is for things you've managed to miniaturize to the point of slipping into a pocket easily.