Screws:
Screws should be Metric for smaller items and imperial for construction.
Use M4 10mm screws and M3 8mm screws wherever possible.

Wood:
Plywood should be 23/32 inch (18.26 mm) sanded plywood
Structural pieces are 2x4s, measuring 1.5 inch (38mm) by 3.5 inch (89mm).


Electronics:
All tactile push buttons are 6mm by 6mm by 7mm Usually this includes an LED in the light. to make a button taller, use a higher button.