Quantity   Component name
48 × Cherry Mx Switches (brown) scavanged from a "Cherry MX-Board 3.0 mechanical keyboard" - switches already come with a diode installed, and low-profile keycaps
1 × MCP23017 I2C io-expander + custom breakout board
1 × Atmega32U4 board (Pololu A-Star Micro)
16 × Lego Technic Pins (connecting Top+Bottom + thumb-cluster)
6 × Lego Technic Liftarms (for the hand-rest) (optional)
1 × I2C bridge pcbs + TRRS cable TRRS cables like the ones used for older iphones