As we’re going to be running our robot with a rechargeable battery, we’ll need a way to turn it on and off. Any two-state switch will serve this purpose. Our choice was a key switch, but you can go with anything that pleases your eye.

Stick the switch in the hole and secure it with some hot glue (Figure 1-18). Some switches can be just screwed into the hole, making gluing unnecessary.

Figure 1-18. Key switch hot-glued