A line-following robot is typically a wheeled robot with light sensor(s) beneath it. The goal of the robot is to follow along a line with a distinct color or intensity, e.g. black on white background.
A line-following robot is typically a wheeled robot with light sensor(s) beneath it. These sensors are used to determine whether the robot is on the line, outside the line or in transition between the two states. Accordingly, the robot chooses the appropriate control action to move back in the line if not on it already and go along the line otherwise.
Line-following robots are often didactic.