Arduino adapter lets Sega Genesis controllers work on Philips CD-i

Brief written by the FOSSWire AI editor from Hackaday How we write

October 21, 2026 1 min read 4 reads

Key Takeaway

An open-hardware adapter using an Arduino Pro Micro translates Sega Genesis controller inputs into the serial protocol expected by the Philips CD-i console.

Summary

Hardware hacker MattKC built an adapter to use Sega Genesis controllers on the Philips CD-i, a 1991 multimedia console known for its scarce and poor-quality original controllers. The project uses an Arduino Pro Micro to poll the Genesis pad's simple pinout via DB-9 connector, then translates button states into the serial data stream the CD-i expects from its mouse-like original peripherals. The CD-i's unusual input design, built for pointing devices rather than traditional gamepads, complicates the translation but remains manageable once understood.

How the adapter bridges two controller eras

Arduino Pro Micro handles protocol translation between Genesis pad and CD-i
DB-9 connector on Genesis side uses simple strobed pin reading for button states
CD-i expects serial data stream, not direct pin states like Atari-compatible ports
Console was designed for mouse-like inputs, requiring translation of directional pad to relative movement data
BlueRetro mentioned as alternative wireless solution for similar retro controller adaptation

Original reference: hackaday.com →