CHAPTER 6 ■ ROBOT LINE-FOLLOWINGAs long as there is enough contrast with the line, then it doesn’t matter what shade of floor you have.
The robot is designed to follow either a darker line on a lighter floor or a lighter line on a darker floor.
Picking Line Marking Material
How should you make your line? Painting the line can work very well. With paint, there is a wide variety
of colors and glosses to choose from and you can control the line width. Some long-term upkeep may be
necessary, but generally a painted line tends to be very durable. However, painting entails preparation time
and is permanent.
Alternatively, wide-head marker pens work well on poster board. Make sure the lines are wide enough
and cover the background thoroughly. Spotty, faded, or broken lines can cause the robot to drive off course.
For household courses, most people prefer tape lines. You can create, adjust, and remove non-permanent
tape courses quickly. Tape rolls are easily obtained and come in the desired range of widths. Glossy (shiny)
white cloth tape or flat (non-shiny) black cloth tape provides the highest contrast and thus is easiest for the
robot to follow. Ordinary semi-translucent masking tape may not adequately cover the color and pattern of
the floor underneath it.
Watch out for glossy dark materials. The shine reflects more light than you may realize, and it may not
appear dark to the robot’s sensors.
Tape lines can leave a sticky residue when removed. This is especially true in hot conditions or if the
tape remains in place for too long. Blue masking tape (see Figure 6-3) or other low-adhesion varieties are
much cleaner than ordinary off-white masking tape. For this reason, I use blue masking tape most often.
Figure 6-3. Ordinary off-white masking tape (bottom) and blue painter’s masking tape (top)