If you’re building a standalone project with an embedded PC (say, a CNC rig or a MAME cabinet) one of the easiest ways to get instructions to the software is using the PC’s baked-in keyboard interface. But if you don’t want to actually use a keyboard to control the thing, you need some way to convert button presses and/or joystick movements from your custom control panel into signals that look like keyboard input.

In this offering, UK hacker Rupert Hirst shows us how to reverse-engineer the key matrix on a scrap keyboard and attach a breakout board, ready to wire straight to the switches in your custom control panel. Sure, manually mapping the membrane switches with a multimeter may be a bit tedious when compared to using a drop-in keyboard simulator like PoLabs’ PoKeys, but it’s also a lot cheaper, and a lot more instructive.