The sound that people can hear is produced by the vibration of objects, and its frequency is in the range of 20HZ-20KHZ ultrasonic sensor. Those exceeding 20KHZ are called ultrasonic waves, and those below 20HZ are called infrasound waves. The commonly used ultrasonic frequency is tens of KHZ- tens of MHZ. Ultrasonic wave is a kind of mechanical vibration in elastic medium, which has two forms: transverse vibration (transverse wave) and longitudinal vibration (longitudinal wave). Longitudinal oscillation is mainly used in industrial applications. Ultrasonic wave can propagate in gas, liquid and solid at different speeds. In addition, it also has refraction and reflection phenomena, which are attenuated in the process of propagation. The frequency of ultrasonic wave propagation in air is low, generally tens of KHZ, but it is high in solids and liquids. It decays quickly in air, but it propagates in liquid and solid, with less attenuation and farther propagation. Characteristics of using ultrasonic waves
Ultrasonic sensor composed of piezoelectric crystal is a reversible sensor, which can convert electrical energy into mechanical oscillation to generate ultrasonic waves, and when it receives ultrasonic waves, it can also be converted into electrical energy, so it is divided into transmitter and receiver.
Equipment. Some ultrasonic sensors can both send and receive. This paper only introduces a small ultrasonic sensor, which is slightly different from receiving. It is suitable to spread in the air, and its working frequency is generally 23-25KHZ and 40-45KHZ. This sensor is suitable for ranging, remote control, anti-theft and other purposes.
This species includes T/R-40-60, T/R-40- 12, etc. (where t stands for transmission, r stands for reception, 40 stands for the frequency of 40KHZ, and 16 and 12 stand for its outer diameter in millimeters). There is also a sealed ultrasonic sensor (MA40EI type). Its characteristic is waterproof function? (but can't be put into water), it can be used as the feed position and proximity switch with better performance. There are three basic types of ultrasonic applications: transmission type for remote control, burglar alarm, automatic door, proximity switch and so on. Single reflection type is used for ranging, liquid level or material level; Reflective type is used for material flaw detection and thickness measurement. By transmitting the sensor (or wave transmitter),
Receiving sensor (or wave receiver), control part and power supply part. The transmitter sensor consists of a transmitter and a ceramic vibrator transducer with a diameter of about15 mm. The function of the transducer is to convert the electric vibration energy of the ceramic vibrator into super energy and radiate it into the air. The receiving sensor consists of a ceramic vibration sensor and an amplifier circuit. The transducer receives the wave, generates mechanical vibration and converts it into electric energy, which is used as the output of the sensor receiver, thus detecting the transmission overload. In practical use, the ceramic vibrator used as the transmitting sensor can also be used as the ceramic vibrator of the receiving sensor society. The control part mainly controls the pulse chain frequency, duty ratio, sparse modulation, counting and detection distance sent by the transmitter.
How's it going? I wonder if you know the introduction of the principle of ultrasonic sensor? If you say it may seem particularly difficult, it is even harder to break it down for everyone to see. Ultrasonic sensors are widely used. If you are interested, you can buy related books online or in bookstores for further study. Now with the continuous progress of science and technology, there are also scientific and technological products such as sonic toothbrushes, which can also be studied online. Well, today's research on ultrasonic sensors is over. Thank you for watching.
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