Catalogue

Rubber-tyred wheels that push onto the 3 mm D-shaft of an N20 gearmotor. Sold singly, so a two-wheel robot needs two and a four-wheel one needs four. The D-shaped bore only goes on one way round, which is what stops the wheel slipping on the shaft under load.

A micro metal gearmotor with a 3 mm D-shaft — small enough for a palm-sized robot, geared enough to actually move it. 300 rpm is the middle of the N20 range: quick enough for a line follower, slow enough to have usable torque. Run it from a driver, not from a microcontroller pin. The N20 wheels we stock fit this shaft directly.

A dual H-bridge on a board with a heatsink and screw terminals — two DC motors forwards and backwards with speed control, or one stepper. The workhorse for small robots and anything with wheels. It is an older bipolar design and drops a couple of volts across the bridge, so motors run slightly slower than the supply suggests and the heatsink gets warm under load. The on-board 5 V regulator can power your microcontroller, but only with the jumper fitted and the motor supply under roughly 12 V — above that, remove the jumper and feed the logic separately.