I wanted to add a USB hub to this project so I could use other retro console controller via USB. I also wanted to make it look as original as possible, I decided to add a 3 port USB board to the top edge of a game cartridge. This means when you open the flap on the NES it looks like there’s a game but actually its a USB hub.
I first had to test that the usb board i had would work using the original cables, which normally get used to connect the front PC Board (this one) to the back USB board. I soldered a usb socket to the end of the original cable and tested in my pc. It worked so I started designing the NES cartridge hub.
For making the game cartridge USB hub, I bought a small USB hub that I took the casing off to make it as small as possible so it would fit inside the game cartridge. Now I need to turn my round 4 port hub into a straight line hub and i used an old PC front panel USB sockets(was in a floppy drive slot). I could only get 3 ports on the top edge of the cartridge because of the board imwas using. I lined up the 3 ports on the front of the cartridge and made markings so i knew were to file.
I also used the dremel to trim sections off the board to make it fit into the cartridge. Liked pictured below.
I now filed out the 3 holes into the cartridge to house the usb sockets in. When I got everything lined up and the cartridge closes fine, I now started to think about soldering the usb ports to the hub.
I measured up the cables and then soldered the cables straight to the hubs USB ports on the underside of the board. Tested all 3 ports in a computer to check they work and then close the cartridge up and put inside the cartridge holder on the NES.
You might not need to do this if you are using V2 of the Retropie GPIO adapter.
Due to the location of the Raspberry Pi within the NES case you will also need to remove the middle of the cartridge holder, so the holder slots over the Top of the Retropie GPIO adapter. I used a dermal to cut the hole in to the middle of the holder.
Now slide the USB cartridge into the holder and plug the usb into the raspberry pi and site the holder back on top of its screw mounts and tighten the screws up after you are happy everything works ok.