Even with the V3 boards not being perfect for the buttons, I still managed to make them work. The two jumper wires on the Arduino Rp2040 is for a special function of the io expander. I am not sure I want to use the feature, but still want to test it. Each wired pin connects to an output on the io expander, which should output a block of pin states as an interrupt for the Arduino.

Testing and coding will commence this week. I remember when this project was about a wrist mounted Cyberdeck (pipboy) with the raspberry pi z2, but I guess it's turning into an HMI problem. Wearables seem to always need a way to make the interactions more intuitive or have high enough functionality that they aren't a pain to use. A device thats tedious to use, stops getting used. 

Writing this out more for myself than anyone else. 

Best,

N.