Quantity   Component name
4 × Sewing Bobbins Standard plastic sewing bobbin
1 × 30 Gauge wire
4 × Neodymium Magnets 1/4" by 1/16"
1 × Various Lego see included file BOM for current list most important are the technic bushes
1 × Arduino
1 × H-Bridge Motor Driver
4 × LED (red)
4 × LED (another color)
4 × Resistor matched to your LED for a 5 volt supply
1 × foot of electrical tape
4 × paper hole reinforcements
11 × Dupont conectors
4 × 1/4"-28 x 1/4" set screws
1 × A1324 Hall Effect sensor