Page 50 - The Unofficial Guide to Lego Mindstorms Robots
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3
Trusty, a Line Follower
In this chapter:
Building Instructions
Some Tricky Programming
The Light Sensor
Idler Wheels
Using Two Light Sensors
Online Resources
In this chapter, you'll build Trusty, a simple robot that exhibits a behavior called line following. This means that Trusty, shown
in Figure 3-1, can drive along a sort of ''track" defined by a thick black line on the floor. Your RIS kit includes a "Test Pad,"
which is simply a large piece of white paper with some black lines and other marks on it. Trusty will follow the large black
oval on this paper faithfully until he runs out of battery power.
Figure 3-1.
Trusty, a line follower
As you can see in Figure 3-1, Trusty's main feature is a downward pointing light sensor. This sensor is the key to line
following. The light sensor can distinguish between the white background of the Test Pad and the black line drawn on it. As
