Yes! Actually, one of the first cards we built internally is a little Arduino-compatible one with a SAMD21 microcontroller and an external-facing 0.1" pin header for GPIO.
Will the expansion cards work if plugged into a USB-C port on another laptop or desktop? (Assuming I have driver e.g. Linux installed).
Yep! Most do not require any custom drivers.
Woooow. This has a huge market potential among hobbyists.
Wow that's actually a really cool idea
I love it!
Will your specs include metric or just imperial measurements like you just used here?
Fear not, modern inches are metric inches:
since the adoption of the international yard during the 1950s and 1960s, it has been based on the metric system and defined as exactly 25.4 mm.