DIY PSX to USB is A-OK! - Make

PSX RetroPad Adapter

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PicoMemcard: DIY USB Memory Card for PSX

8bitdo releases DIY Modkits for PS1 & PS1 Classic

PicoMemcard - Share Project - PCBWay

ps2portable How to make a ps2 portable

Renegade Labs EZ GBZ DIY Kit Review (Hardware) - Official GBAtemp Review

How to make a DIY PS2 controller to a USB converter - Quora

Zero delay USB Joystick Encoder. – S-Config