Amazon.com: Handle Joysticks USB Adapter, Mini Handle Converters for RasPi for Mister FPGA for PC Game Controller Conversion Adapter for Genesis, for Atari Game Controllers (for CD32 Handle Adapter) : Video Games
Homemade USB adapter for 9 pin Atari C64 Amiga Joysticks - YouTube
4 Port USB Adapter for Atari Joysticks and more from iCode on Tindie
4 Port Retro USB Adapter for Atari Joysticks and Paddles (Plus Edition) – iCode