symlink.dk writes -

This page describes how to build a USB-keyboard in the form-factor of an old C64 breadbox. Actually, with little modification it can be used for any kind of keyboard, since the source code is available, and all that needs to be done is to modify the key-to-scancode mapping.

The c64key is based on Objective Development’s AVR-USB firmware only USB stack for Atmel AVR microcontrollers, and the simple HIDkeys example they provide. The implementation presented here has a more elaborate keyboard scanning routine, and allows multiple keys to be pressed (and detected) simlutaneously.

SYMLINK.DK – Electronics – Link.