I added a vintage 9-pin port to my C64 mini, including working F-keys and extra buttons. Goodbye broken usb joystick! : r/c64
USBJoy2.0 - adapter. Connect your Atari Amiga C64 joystick to PC! Develop your own usb device! - Polish electronics for 3D printers, CNC, robotics, retro computers
Converting the “Competition Pro Extra USB” to C64/Amiga/Atari DB9 – pagetable.com
C64 Joystick Adapter - Share Project - PCBWay
Amazon.com: The C64 Mini +1 Additional C64 Joystick : Video Games
How to Convert Any Commodore Joystick from 9-pin to USB using The C64 Joystick - YouTube