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110 CHAPTER 4 ■ SENSORS

Figure 4-1. Some breadboard circuits

The circuit on the left in Figure 4-1 was connected with 22 AWG hook-up wire. The circuit
itself is a Sharp IR detector module, purchased from Radio Shack, which uses two modulated
IR LEDs.
The circuit on the right in the figure was standalone and did not require any hook-up
except for the five-volt DC battery. It consisted of one IR LED, one IR phototransistor, and a
transistor circuit.
In the previous chapter, I used servos for some motion. Early on, before I started making
my own connectors, the servo connectors came in quite handy, but they were expensive
compared with wire and connectors. To make your own, you’ll need the following (pictured in
Figure 4-2 from left to right, clockwise):
• Female .100” header: The same hook-up as a servo.

• Make .100” header: The pins you’ll need to connect to the Parallax Board of Education.
• 22 AWG hook-up wire (different colors): Fits the pins nicely, and as far as wire, it costs
the least.

• .100” header socket: Comes in many different size combinations.
• Crimper (not shown): Necessary for crimping the wires to the headers.