CHAPTER 22 ■ SOLDERING AND CONNECTING- Repeat the process for the other motor.
- Unplug the hair dryer or heat gun. Set it someplace where it can cool safely.
During heating, the heat-shrink tubing may pull away a bit from the end cap of the motor. That’s all
right, but in general, the heat-shrink tubing should be covering almost all exposed metal. Because the tubing
shrinks in length to some extent, remember to cut pieces that are longer than the joint you want to cover.
Not only does heat-shrink tubing make your robot guts look more professional, it also provides some
short-circuit protection from wires touching during the inevitable spills, falls, and crashes.
Adding Connectors
It would be possible to solder the motors directly to the line-following circuit board. However, this would
make it difficult to assemble and disassemble the robot. Additionally, if a motor needs replacement or the
motor is going to be borrowed by another robot (the horror!), the motor would need to be desoldered from
the circuit board.
There is a better way. The motor wires can conclude in a connector, which you can then attach or
detach from a board as necessary without soldering.
Molex KK Connectors
There is a huge variety of connectors available. I happen to be partial to Molex KK connectors. They’re
reasonably small, come in widths that allow from 2 to 15 pins, and are available to fit in standard 0.100-inch-
spaced breadboard holes. Figure 22-12 shows a Molex KK housing being pushed into the matching Molex
KK header on the circuit board.
Figure 22-11. Heat-shrink tubing after heating; protecting and insulating soldered terminals