Randofo writes – “How to hack a USB keyboard or any keyboard for that matter. Send inputs into the computer without a pesky microcontroller. Once you have a hacked keyboard you can use it for a number of functions and attach a number of different types of switches. You can build your own typewriter keyboard (video here)… You can use a photocell as a switch. You can hook it up to a capacitance sensor and use just about anything to trigger an event in a Flash movie. You can hook it up to some floor switches and develop your own DDR game.” – Link.
HOW TO – Hacking a USB Keyboard (Make a typewriter keyboard)