Datasheet
Chapter 7 • Navigating with Infrared Headlights
216 • Robotics with the BOE Shield-Bot
Chapter 7. Navigating with
Infrared Headlights
The BOE Shield-Bot can already use whiskers to get around, but it only detects obstacles
when it bumps into them. Wouldn’t it be convenient if the BOE Shield-Bot could just “see”
objects and then decide what to do about them? Well, that’s what it can do with infrared
headlights and eyes like the ones shown below. Each headlight is an infrared LED inside a
tube that directs the light forward, just like a flashlight. Each eye is an infrared receiver that
sends the Arduino high/low signals to indicate whether it detects the infrared LED’s light
reflected off an object.
Infrared Light Signals
Infrared is abbreviated IR, and it is light the human eye cannot detect (for a color image of
the visible light spectrum, see http://learn.parallax.com/lightspectrum). The IR LEDs
introduced in this chapter emit infrared light, just like the red LEDs we’ve been using emit
visible light.
The infrared receivers in this chapter detect infrared light, similar to the phototransistors in
the last chapter. But, there’s a difference—these infrared receivers are not just detecting
ambient light, but they are designed to detect infrared light flashing on and off very quickly.
The infrared LED that the BOE Shield-Bot will use as a tiny headlight is actually the same
kind you can find in just about any TV remote. The TV remote flashes the IR LED to send
messages to your TV. The microcontroller in your TV picks up those messages with an
infrared receiver like the one your BOE Shield-Bot will use.
Infrared
LED
Infrared Receiver
Infrared Receiver
Infrared
LED