I didn't do an actual project log, honestly because it was that fast, but I have rewired my ION iCade Core with a USB controller. This replaces the Bluetooth controller that never worked well, and then stopped working once my Android devices went past Android 5.
The iCade Core is not a high end device to begin with. I think the retailed at around $80 - 90 CDN. I nabbed mine on sale for $45 about 3 or 4 years ago. The advantage of doing a build this way, assuming you can find one, is I get to avoid my dread full wood working skills. I have dropped everything back into the case, no problem. I think I'm so happy with the result I will actually repaint. I do have that airbrush an booth looking for projects.
The iCade is really easy to open up, six small head phillips screws, none buried under rubber feet or labels. Although the buttons and stick are on the cheap side, the are standard arcade style micro-switches. They look like Happ Microswitches, but they're way cheaper. You could easily, however, swap all the buttons out for better ones. And the stick as well, as it's a standard 4 switch.One of the nice to builds I'm now considering is adding an adjustable restrictor plate, so I can switch this to 4 way. The builtin in stick has no plate, so it's possible to hit up and left at the same time. Some games require this, some games freak with the extra inputs.
For the controller I found this guy. At about $14 CDN direct from China (includes shipping!) it doesn't get much less expensive. This board is a tab bigger than the Bluetooth one I removed, but not much. It came with pre-crimped wires and the USB had a nice stress reliever on it. Once I sorted which parts of the micro switches to connect to it was just a matter of swapping 1 for 1. Further, the Bluetooth board had a 5V barrel plug that left a hole just about the perfect size for the bottom of the boot.
I still have 4 buttons open on the controller, so I may order a couple of small push buttons to add for additional controls, like coin slot and 1-Up.
A fun little project that only took about an hour.