The working principle of inductive sensor L is based on the law of electromagnetic induction. When a metal object approaches the sensor, it will cause a change in the magnetic field in the coil, thereby generating an induced electromotive force in the coil. By detecting the magnitude and direction of the induced electromotive force, it is possible to determine whether an object is approaching and its position status. Inductive sensors are widely used in automation equipment such as machine tools and assembly lines, for detecting the position of workpieces, counting, and controlling the movement of robotic arms.

Distance sensor D or photoelectric sensor D uses the reflection or transmission of light on the surface of an object to measure distance. The transmitter emits light, which is reflected or transmitted back to the receiver when it encounters an object. The distance between an object and a sensor can be calculated by measuring the time it takes for light to be emitted and received, or the intensity change of the light. This type of sensor has broad application prospects in fields such as smart homes and autonomous driving.