It was predicted a few months back by CD-i member Simon Laroche, and it will be indeed possible in the near future to develop a USB2CD-i adapter which allows us to connect modern USB controller to our CD-i player, next to already known examples of the SNES2CD-i and Sega2CD-i. Together with the upcoming Bluetooth version of the BlueRetro (which will also support CD-i) we will have more options to connect all kinds of controller to CD-i. Today CD-i member TWBurn (Jeffrey Janssen) shared his progress on the USB CD-i interface, which will make it able to use modern USB controllers on your CD-i player. In fact he created an Arduino Library for CD-i controllers. The code is released under the GNU General Public License. TWBurn: "I've created an Arduino Library which can be used to emulate a CD-i controller. Currently it supports four different modes (Relative, Maneuvering, Absolute Coordinate and Absolute Screen). I'm hoping to also add Keyboard support once I can find some documentation on the subject. I've been using this library together with a USB Host Shield to connect some modern controllers (in my case a Wii U and Switch Pro controller) to the CD-i with acceptable to good results, depending on the title used. I've included these as examples in the library."
The library can be found on:
TWBurn continues: "For future updates I hope to include some more examples (like an USB mouse, keyboard), workout some issues, as well as moving my hardware beyond a prototyping phase so I don't have random wires running over my desk. I was missing the CD-i specification for keyboards, I was using documentation on http://www.icdia.co.uk/docs/ for the pointing devices, but the links to the keyboard specification there were dead. I know it's rarely used, but for completion I'd wanted to include it. A simulated controller may not function as expected in all games. For example using the Joypad examples with "The Apprentice" game, the running animation keeps restarting and also the maximum running speed is never reached. This might have something to do with a delay between packets sent to the CD-i player."
- AnalogStick: Uses an analog stick connected to the analog inputs of the Arduino as input for a CD-i Maneuvering Device. Clicking the stick serves as button 1.
- MagicNS: Uses a Switch Pro controller connected to a Magic NS adapter, connected to a USB Host Shield as input for a CD-i Maneuvering Device. Both the left stick and d-pad are mapped to movement. With the left/right triggers a speed can be selected.
- WiiUPro: Uses a WiiU Pro controller connected to Bluetooth adapter, connected to a USB Host Shield as input for a CD-i Maneuvering Device. Both the left stick and d-pad are mapped to movement. With the left/right triggers a speed can be selected.
- WiiUProAbsolute: Uses a WiiU Pro controller connected to Bluetooth adapter, connected to a USB Host Shield as input for a CD-i Absolute Coordinate Device. The range of the left stick is mapped to the full screen, the right stick provides a smaller offset for fine tuning.
CDifan, the webmaster of ICDIA.co.uk, informed us that he is going to look into the missing documents about the keyboard configuration as Jeffrey mentioned!
[Thanks, TWBurn (Jeffrey Janssen) for sharing this and working on homebrew projects on CD-i]