CHAPTER 25 ■ LAUNCHING THE LINE-FOLLOWERIn the first frame, the right LEDs are lit. Since the robot is following a dark line on a light floor, the right
motor must engage when the right LEDs are lit. By frame two, the left LEDs have been turned on, and only a
brief residue of light remains in the right LEDs. So, at this point, the left motors are engaged but the power to
the right motors has been disengaged.
Frames three, four, five, and six all show the robot properly powering the left motor to turn the corner.
The right LEDs, and hence the right motor, are disengaged at that time.
By frame seven, both LEDs should probably have been lit since the curved line appears to now be
centered. Both sets of LEDs are lit in frame eight, but by then the robot has oversteered. So, in frame nine,
the right LEDs are lit and the right motor corrects the course.
In frame ten, the robot has both sets of LEDs and both motors engaged and is heading straight down the
straight line. Beautiful!
Figure 25-11. Ten video frames of the line-following robot turning a corner