Ultrasonic proximity switch sensors are devices that use sound waves to measure distance. They can emit high-frequency ultrasound and receive reflected sound waves to determine the position and distance of objects. This type of sensor is widely used in various fields, such as automotive reverse radar, industrial measurement, liquid level control, etc. The core advantage of ultrasonic sensors is that they are not sensitive to light conditions and can operate stably in various environments, including environments with dust, smoke, or mist. Simply put, ultrasonic sensors accurately perform non-contact measurements by sending and receiving sound waves to "hear" the surrounding environment.