Quantity   Component name
3 × M3 12mm pan head screws (1 per output)
1 × Mini neodymium magnets (2 per input/output) 3x6mm I get mine at Daiso 100yen store for now. Might need a cheaper source.
3 × M3 18mm pan head screws (1 per input)
3 × M3 5mm compression springs (1 per 18mm screw) 0.3x4x5mm
3 × M3 nuts (1 per 12/18mm screw)
3 × M3 nylon lock nuts (1 per 12/18mm screw) It would be best if all nuts were lock nuts, but space and money may make you choose otherwise.
4 × M3.2 non-insulated ring terminals (so far 1 per input/output)
4 × M2 5mm wide-flat-head "laptop" screws (4 per lid)
1 × Your favorite 3D printing material or whatever you decide to use to make the boxes.
1 × Various sensors, LEDs, potentiometers, and whatever else you'd like your circuits to do.