Robot Building for Beginners, Third Edition

CHAPTER 10 ■ LEDS

The LED’s shape acts as either a collimating lens (light straightening—like a narrow-beam spotlight) or
as a light distributor. If you shave down the dome of an ordinary T 1 ¾ LED (use medium-grain sandpaper
and then polish with extra fine sandpaper or paste) you’ll end up with a peculiar glowing circle instead of a
directed beam (see Figure 10-4).

Multiple LEDs are often combined into a group package (see Figure 10-5). A numeric LED (often found
in clocks) is nothing more than seven individual LEDs arranged into the number “8.” By lighting up specific
LEDs, it can form a variety of numbers and letters.

Figure 10-3. A variety of discrete LED shapes

Figure 10-4. Homemade pinpoint LED

Figure 10-5. Multi-segment numeric and bar-graph LEDs