As my first project, I was going to mod my Gamepad F310 (pic below) to become a gamepad input.
Basically, I was going to put its innards in a project box and attach each pinout to a header. Then, using ribbon cable, I could make my own game controllers (IE attach arcade stick to D-pad) for my PC. That's the easy part. The hard part? Controllers with keypads:
Specifically, I wanted to rig up the Atari 52
controller to my computer. However, the Gamepad F310's 12 button max (10 button on XInput mode) rendered this task difficult. My idea? Use a keyboard. However, I don't know how I would accomplish this. The Atari controllers shown here use matrices. (If you know how they work, skip the next paragraph.)
I'll use the Atari 5200 controller for this example. Basically, each column has its own pin on the controller plug, and each row has its own pin. The console pulls each of the columns low, in turn, so when you push a button, that row's pin is pulled low.
Now, my question is, how do I rig this up to a keyboard? I don't want to mod the original controller, I just want to know how to encode the matrix as a keyboard input. Any ideas? Thanks in advance!

Basically, I was going to put its innards in a project box and attach each pinout to a header. Then, using ribbon cable, I could make my own game controllers (IE attach arcade stick to D-pad) for my PC. That's the easy part. The hard part? Controllers with keypads:


Specifically, I wanted to rig up the Atari 52


I'll use the Atari 5200 controller for this example. Basically, each column has its own pin on the controller plug, and each row has its own pin. The console pulls each of the columns low, in turn, so when you push a button, that row's pin is pulled low.
Now, my question is, how do I rig this up to a keyboard? I don't want to mod the original controller, I just want to know how to encode the matrix as a keyboard input. Any ideas? Thanks in advance!