As luck would have it, around this time there was a lot of discussion on the Cyberdeck Cafe Discord about developing a common cartridge format that cyberdeck builders could use on their machines. The leading idea at the time was to base it on something like the Sega Genesis cartridge, as the interface was well-known, and getting cases and edge connectors would be no problem. But it still had the same problem as my first idea, the need to spin up a custom PCB for each and every cart.

I had been posting some progress images about the reComputer in the Discord, and a couple members asked if it would be possible to retool my cartridges into something more broadly compatible since they were just USB anyway.

So the first step was to develop cartridges that had the same profile (as I wanted them to retain compatibility with my own deck) but could have a variable length. This was done through OpenSCAD's customizer, so that anyone could create STLs for custom cartridges even if they didn't know any CAD themselves.

Carts could now be smaller or larger than the original PreComputer carts, which combined with some of these modern flash drives, made for a surprisingly compelling storage device.

I also implemented code that would put an opening in the back of the cartridge for an antenna. So instead of just being purely for storage, they could also hold things like Bluetooth and WiFi adapters. While I have yet to try it due to the heat generated, I'd like to even do one for an RTL-SDR.

The final step was to come up with some kind of cartridge slot that could be easily added to another cyberdeck. After all, we didn't want to just limit this idea to 80s era VTechs. So I created a design that combined elements of the adapter for the reComputer with a printed slot that you could bolt onto your deck -- all you need to do is make a rectangular opening and place the screw holes.

I officially presented the project as part of the Cyberdeck Cafe's Virtcon 2021 event:

A few cyberdecks from other builders have already implemented support for retroCART, and if you're interested in learning more (or adding it to your own project), you can check out its Hackaday.io page:

retroCART USB Cartridge System