Designing and building your own keyboards is great fun and usually results in better keyboards than money can buy, but the fact that mechanical switches are rather expensive and an average keyboard contains a lot of them makes the prospect a little bit scary for beginners. That's why I decided to make a "minimal viable prototype" keyboard that demonstrates most of the challenges and lets you try your skills without breaking the bank.
As you can see, there are only six keys. That means you probably won't be able to type with it, unless you invent some aggressive chording scheme, but you can use it for things like volume keys, switching workspaces, switching keyboard layouts or dedicated arrow keys.
The board runs CircuitPython, so that it is easy to program it and to explain how the programs work. Of course nothing stops anybody from programming it in C or Arduino or anything else, it's just a regular SAMD21 microcontroller.