This is designed to allow a simple plug and play for 3 or 4 players on PGM games. A 5v usb adapter port has been added for compatibility with undamed and other controller adapters as there is no +5v available from the port. If you are using a controller with a neo geo pinout, the power is not needed.

BOM

1) 2x D sub 15 connectors for controller - https://www.digikey.ca/product-detail/en/amphenol-icc-fci/D15P33E4PA00LF/609-6495-ND/1537430

2) 1x female 34 pin Socket - https://www.ebay.ca/itm/20pc-Pin-Female-Header-Dual-2-54x2-54mm-H-8-5mm-Right-Angle-90-2x17p-2x17-34p/131957761777?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

These were the cheapest things I could find and they work well. If someone has a better solution, I am all for it. You can also use a female socket and a straight IDE cable but that adds to the cost.

3) USB connector - https://www.digikey.ca/product-detail/en/amphenol-icc-fci/10118194-0001LF/609-4618-1-ND/2785382

I have also made an adapter for CPS2 games here - https://oshpark.com/shared_projects/LD8eawUz

I have more adapters designed but I need people to help me test.