What is the working principle of ultrasonic sensors?
2 Answers
Principle: Ultrasonic sensors mainly consist of two types of materials: piezoelectric crystals (electrostrictive) and nickel-iron-aluminum alloy (magnetostrictive). Electrostrictive materials include lead zirconate titanate (PZT), etc. The ultrasonic sensor composed of piezoelectric crystals is a reversible sensor that can convert electrical energy into mechanical oscillations to generate ultrasonic waves. At the same time, when it receives ultrasonic waves, it can also convert them into electrical energy. Therefore, it can be divided into a transmitter or a receiver. Below is a related introduction to ultrasonic sensors: 1. Components: Commonly used ultrasonic sensors are composed of piezoelectric wafers, which can both emit and receive ultrasonic waves. Low-power ultrasonic probes are mostly used for detection. They come in many different structures, including straight probes (longitudinal waves), angle probes (transverse waves), surface wave probes (surface waves), Lamb wave probes (Lamb waves), and dual probes (one probe emits, one probe receives), etc. 2. Performance indicators: The core of an ultrasonic probe is a piezoelectric wafer in its plastic or metal housing. The materials that make up the wafer can vary. The size, diameter, and thickness of the wafer also differ, so the performance of each probe varies, and its performance must be understood in advance before use.
I'm a car enthusiast and particularly enjoy discussing fun technical tidbits, like ultrasonic sensors. Their working principle is actually quite cool, similar to a bat's sonar system. The sensor emits high-frequency sound wave pulses inaudible to the human ear, which propagate outward and bounce back when they hit an object ahead. The receiver captures the echo and calculates the time interval between emission and reception. Since the speed of sound is approximately 340 meters per second, multiplying the time and dividing by two gives the distance. In cars, they're usually mounted on bumpers as parking aids, triggering warning beeps when obstacles are detected. These devices perform well in rainy or foggy conditions too, unlike cameras that tend to blur, and can detect low-lying objects like children or pets. Maintenance simply requires keeping the surface clean to prevent dirt obstruction – truly a simple yet brilliant design!
