I wanted a solution to adding motors that is non invasive, does not destroy any "prime" parts, and simple to use. This is what I came up with.
You will need for each interface:
1 2x2 tall Lego brick, any color
1 2 position screw terminal block
about 2" solid core wire, 22-24 AWG
Small drill bit or finishing nail
Diagonal cutting pliers, smaller is better
Fine tip sharpie