The circuit uses sensors to detect changes in light intensity. When the sensor detects a change, it sends a signal to the microcontroller, which then triggers the necessary actions to follow the black line.
Most commonly, infrared sensors are used in these circuits. They emit infrared light and measure the amount of light that is reflected back. When the sensor is over a black line, the amount of reflected light decreases, signaling the presence of the line.
No, the surface must have a significant contrast between the line and the background. For example, a black line on a white surface or a white line on a black surface would work, but a black line on a dark grey surface may not be detected accurately.
Yes, some circuits have multiple sensors that can detect and follow multiple lines at once. The microcontroller can be programmed to switch between the different sensors and follow each line separately.
The precision of the circuit depends on the quality of the sensors, the programming of the microcontroller, and the surface it is being used on. With proper calibration and setup, these circuits can be very precise and accurately follow a line.