Keyboard hack/admin buttons

Now I want to have separate buttons for quitting and pausing games. This would've been possible with combo button presses, but the basic controls should be obvious to a moron playing on the machine for the first time. All of the eight buttons were already taken on each joystick, so how can I add a few more buttons? The answer is to bust open an old keyboard and connect buttons to the circuit board. This is very cheap, almost free if I didn't have to buy a soldering iron and solder and wire. But even with that junk, it's still half the price of buying a dedicated key encoder.

In the picture below, the middle green board is from an old Microsoft natural elite keyboard. The soldering points are in a logical location and it's easy to solder new wires to them. Some newer keyboards (like a USB keyboard that I opened) have such a tiny encoder chip on the board that there are no solder points (everything is covered up).

At the maximum, I want to add five buttons: Escape, pause, speed-up, coin 1 and coin 2 (actually I just want the coin buttons to be available for the inevitable addition of a coin door). For this keyboard encoder, it requires nine wires for those five buttons. I don't need every key combination, which would've required twenty-four wires and a couple more wiring blocks.