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Bots /The Ultimate Palm Robot/ Mukhar & Johnson / 222880-6 / Chapter 9

Chapter 9 Sensors and Enhancements 233

❏ Actuators
❏ Sensors

There’s not too much we need to say about the base. If you’ve already built
the Palm robot, you know all there is to know about the base. (Reminder: Alu-
minum frame and acrylic deck.) In the last few chapters, we’ve seen how to
program the processor of the robot. That leaves the actuator and sensors—
also known as the input and output devices.

Most of the machines we work with have some sort of input and output.
That’s what makes them useful to us humans. Through a small number of in-
put devices (such as a steering wheel, pedals, or shift lever) a car accepts input
and outputs power to move us around. A television accepts input from but-
tons, dials, and remote controls and outputs video to us. A computer accepts
input from keyboard, mouse, and other devices, and outputs data to us.

Likewise, our Palm robot uses input and output devices. The Palm robot
uses an infrared ranger to detect distance to objects. It then determines which
servos to turn on or off to move the robot in various directions. As we’ve seen
in previous chapters, we can use these rangers and servos to accomplish a
good variety of behavior. If you tried some of the sample programs available
on the web (see Chapter 5), you’ve seen the robot follow walls, copy a pattern
drawn on its screen, run away from objects, or chase objects—just to name a
few behaviors.

But there are some things our robot cannot do. BEAM robots, which we
looked at in Chapter 1, can be built to seek out or avoid light. Our Palm robot
can’t do that.

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Monday, May 12, 2003 4:33:31 PM