I have been thinking about interfacing with my gameboy for a while via the link cable but had no way, other than destroying a cable, to connect it to an arduino or raspberry pi.
Eventually I stumbled upon a blog post where someone had written about the creation of a link cable breakout board. Unfortunately they didn't distribute their CAD file but I figured now would be a good time for me to learn how to create a PCB too.
This is my result, it's very basic but after sending the gerbers to OSHPark I got some boards back which work great.
More about how I made it can be found on my blog: https://palmr.co.uk/posts/26---gameboy-link-cable-breakout/
This project — schematics, board layout, gerbers and documentation — is licensed under a Creative Commons Attribution 4.0 International Licence by Nick Palmer.
You are free to share and adapt the design, including commercially, as long as you give appropriate credit.