Page 314 - Making things move_ DIY mechanisms for inventors, hobbyists, and artists

Chapter 10 Projects 291

camera phone can, and you should see a faint glow on your screen. (In the
pictures in this section, I cheated and used a white LED for emphasis; your IR
LED won’t look that bright.)

Integration Recipe:

1. Pick up your whole circuit and plop it into the box. Make pencil marks where
the LED and phototransistor touch the front of the box. Do the same thing
with the switch. Remove the circuit from the box.

2. Use the 1/4 in drill bit to drill holes for the LED and phototransistor to look
through opposite the marks you made in step 1 (see Figure 10-9). This is
easiest to do with a portable hand drill while supporting the box on the corner
of a table. Clean up any splinters with sandpaper or a Dremel tool.

FIGURE 10-9 IR LED (left) and phototransistor (right) peeking through drilled holes