Someone recently uploaded a 3D print design for a dual-controller Atari 5200 adapter. This is to link two controllers together for dual-stick games like Robotron and Space Dungeon. I believe I’ve seen this mod before, but I saw someone on AtariAge printed one and liked it, so I thought I’d write up a quick post about it for 5200 fans!
Files can be downloaded here: https://www.thingiverse.com/thing:2071681