This is my experiment with Ergogen and building a keyboard from scratch.

I had a bunch of RP2040 Zero microcontrollers and Choc Mini switches to play with. Even though I am used to 34 keys, Haigha Mod, and use it as my daily driver, I decided to build one with 36 keys because I can do that without using diodes.

While I did design this keyboard to play with Choc mini switches, I did create a Choc v1 version since it was easy with Ergogen and I wanted to see how to make reversible, hot-swappable PCB.

The Choc mini version of the PCB is in choc-mini and the Choc v1 version is in choc-v1.

Inspired by the Wave Keyboard, I redesigned the keyboard to use 4 pin mini DIN used by S-video to protect the microcontroller from accidentally shorting. The layout of the key switches is the same between the different keyboards, the connection between the two halves is the only difference.

Please download the latest gerber files for the key switch you need from Releases

Remember PCB thickness of 1.6mm for Choc mini means the pins will not pass through the hole. I was fine with this since I use don’t use a case.

PCB for Choc mini keyboard using 4 pin mini-DIN for connecting the halves.

PCBs for Choc mini and Choc v1 using TRRS.

Built out keyboard with Choc mini.

Built out keyboard with Choc Sunset and LDSA keycaps.

The firmware folder contains different firmwares for the board. Currently, it supports KMK and QMK

While creating design I used round-track plug-in.

The RP2040 Zero footprint is a modified version of https://github.com/CountParadox/RP2040-Zero-Kicad. A possible improvement for future is to change it to have the origin in the center so that rotating the footprint is easier.

The footprint for 4 pin mini-DIN is based on the one used in Wave keyboard. I translated it to Ergogen footprint.