There’s plenty of choice for the wheels (Figure 1-14). Just don’t pick any that are too heavy, and make sure that you’ll be able to make the holes for the servo horn attachment. For our robot, we salvaged tires from a remote-controlled car.

Drill two 3 mm holes through both servo horns and the wheel rim. Secure the servo horns to the wheel rims with 3x10 mm screws. Push the servo horns on the servo shaft and tighten them in place with 3x18 mm woodscrews (Figure 1-15).

Figure 1-14. Selection of wheels

Figure 1-15. Servo horn attached to the tire rim and wheel attached to the servo