This chapter covers soldering, with emphasis on soldering smaller pieces, like the motors and the line-following switch. This chapter also describes instances when it's better to not solder certain wires together, but instead to use a connector.
Before attempting to solder the line-following circuit (next chapter), it's prudent to practice on less complicated parts. For example, each motor only needs two wires soldered to it.
The switches, motors, and a few other items (see Figure 22-1) are all independent from each other and from the main circuit board. That makes them short and easy projects to work on.
Figure 22.1. (left to right) Motors, line-following switch, battery ...