What is the Principle of Ultrasonic Sensors?
3 Answers
Ultrasonic sensors work on the following principles: 1. An ultrasonic sensor consists of a transmitting sensor (or wave transmitter), a receiving sensor (or wave receiver), a control unit, and a power supply. 2. The transmitter sensor is composed of a transmitter and a transducer using a ceramic vibrator with a diameter of about 15mm. The transducer converts the electrical vibration energy of the ceramic vibrator into ultrasonic energy and radiates it into the air. 3. The receiving sensor consists of a ceramic vibrator transducer and an amplifier circuit. The transducer receives the wave, generates mechanical vibrations, converts them into electrical energy, and outputs it as the sensor receiver, thereby detecting the transmitted ultrasound. 4. In practical applications, the ceramic vibrator used as a transmitting sensor can also be used as the ceramic vibrator for the receiving sensor. The control unit mainly controls the pulse chain frequency, duty cycle, sparse modulation, counting, and detection distance of the transmitter.
From an electronic engineering perspective, let me explain the principle of ultrasonic sensors: They mainly consist of a transmitter and a receiver. The transmitter emits ultrasonic pulses with frequencies exceeding 20,000 Hz – these are high-frequency sound waves inaudible to the human ear. When the sound waves propagate through air and encounter an object, they reflect as echoes which are captured by the receiver. The key principle is that by measuring the time difference between the transmitted wave and received echo, multiplying it by the speed of sound (approximately 340 meters per second at room temperature), and then dividing by 2, we can calculate the object's distance. This non-contact measurement method is commonly used in automotive reversing radars to prevent scraping accidents. I've also studied factors affecting its accuracy, such as ambient temperature or obstacle material, which slightly influence sound velocity. However, modern sensors incorporate compensation mechanisms to maintain accuracy within about 2 centimeters, ensuring safer and more reliable daily driving.
As a seasoned driver with years of experience, I've personally experienced the practical principle of ultrasonic sensors: imagine the 'beep' sound it emits when reversing—the sensor sends out ultrasonic beams backward. If there's a wall, car, or pillar behind, the waves bounce back. The system quickly calculates the time interval between emission and reception, multiplies it by the speed of sound, and derives the actual distance. This is similar to how bats navigate in the dark—simple yet efficient. In daily car use, it's not just for parking assistance but also works collaboratively in automatic parking systems. I find it particularly useful in rainy weather or when visibility is poor at night, avoiding the hassle of multiple reverses, making it the best helper for novice drivers.
