Rupert, over at Runaway Brainz, wanted to avoid shelling out a lot of money for a custom control interface for a MAME cabinet. To that end he hacked apart an old keyboard, mapped the key signals on the keyboard matrix, and then rewired the board to use the inputs he needed for the new interface. The final product looks very little like a keyboard and very much like the expensive input modules he emulated for his no-cost DIY model.
Hack: Reverse Engineer and Repurpose an Old Keyboard “The Matrix Reloaded” [via Hack A Day]