@sman42 @koen @derPUPE @frameworkcomputer let's do this

an arduino pro micro usb-c would be ideal for a prototype I suppose

https://keeb.io/products/pro-micro-usb-c-version-5v-16mhz-arduino-compatible-atmega32u4

switches could be wired and controlled like in this tutorial here

https://www.instructables.com/Arduino-Mechanical-Keypad-1/

openSCAD design for framework modules:

https://github.com/FrameworkComputer/ExpansionCards/tree/main/Mechanical/OpenSCAD