Datasheet

Chapter 7 • Navigating with Infrared Headlights
218 • Robotics with the BOE Shield-Bot
The pixel sensors inside the digital camera detect red, green, and blue light levels, and the
processor adds up those levels to determine each pixel’s color and brightness. Regardless of
whether a pixel sensor detects red, green, or blue, it detects infrared. Since all three pixel
color sensors also detect infrared, the digital camera display mixes all the colors together,
which results in white.
Infra means below, so infrared means below red.
The name refers to the fact that the frequency of infrared light waves is less than the frequency of
red light waves. The wavelength our IR LED transmits is 980 nanometers (abbreviated nm), and
that’s the same wavelength our IR receiver detects. This wavelength is in the near-infrared range.
The far-infrared range is 2000 to 10,000 nm, and certain wavelengths in this range are used for
night-vision goggles and IR temperature sensing.
Activity 1: Build and Test the Object Detectors
In this activity, you will build and test infrared object detectors for the BOE Shield-Bot.
Parts List
(2) IR receivers
(2) IR LEDs (clear case)
(2) IR LED shield assemblies
(2) Resistors, 220 Ω (red-red-brown)
(2) Resistors, 2 kΩ (red-black-red)
(misc) Jumper wires
 Gather the parts in the Parts List, using the drawings below to help identify the
infrared receivers, LEDs, and shield assembly parts.
With a button pressed and held, the
IR LED doesn’t look any different.
Through a digital camera display, the
IR LED appears as a bright white light.