Step 4: Keyboard hack

I had half way done with the keyboard hack because six months before the starting of this project I built a control panel prototype just to know if it would work.

I got an old PS keyboard and removed the printed circuit board (PCB). Then I soldered a wire to each pin of the PCB (if I had to do it again, I would use a ribbon cable instead). With the maylar and the keyboard layout I was able to determine the definition of each key.

I needed to handle 24 keys:

4 keys for player 1 joystick
4 keys for player 2 joystick
6 keys for player 1 buttons
6 keys for player 2 buttons
1 key for escape button
1 key for insert coin button
1 key for one player start
1 key for two player start

Most games will work OK with this setup.

One of the most difficult things with the keys selection was to avoid the "ghosting" and "blocking" got in some cases:

What this means:

Ghosting: when you press 2 keys you got a third
Blocking: pressing certain keys combinations they blocks others

I created a reference sheet as a helper to choose the right keys as you can see in the picture.
adrian1164 years ago
Im really new to this whole thing. Do you think you could some how explain exactly what to do for a fellow amature? Brilliant project by the way.
I dont get it ether
crusso (author)  17jrobinson4 years ago
I don´t understand your question, please let me know how can I help you.