Line sensors are used in robotics to detect lines or boundaries, usually for line-following robots. These sensors work by emitting light and measuring the reflected light intensity. When the sensor is above a dark surface, such as a black line, the reflected light intensity is low. When the sensor is above a light surface, such as a white background, the reflected light intensity is high.

Line-following robots use line sensors to follow a predetermined path, usually a black line on a white surface. These robots can be programmed to perform various tasks, such as navigating a maze or transporting objects from one location to another. Line-following robots are commonly used in manufacturing, warehousing, and other industries where precise movement along a predefined path is required.

The microbit can be used to control a line-following robot by connecting it to the line sensors on the move motor car. The microbit reads the sensor values and sends commands to the motors to adjust the robot's direction based on the detected line.