Analysis of advantages and disadvantages of ultrasonic sensors

How do ultrasonic sensors handle noise and interference?

Any acoustic noise at the frequency received by the long range ultrasonic sensor may interfere with the sensor's output. This includes high-pitched noise, such as sounds generated by the click of a whistle, safety valve, compressed air, or pneumatic device. If two ultrasonic sensors of the same frequency are put together, acoustic crosstalk will occur. Another type of noise, electrical noise is not unique to ultrasonic sensors.

Ultrasonic sensors use ultrasonic characteristics to measure objects. Because ultrasonic waves have high frequencies, they have many advantages. The wavelength is very short. 1. The diffraction phenomenon is very small, especially with good directivity, which can become ray and directional propagation. Ultrasonic penetration of liquids and solids is very large, especially in opaque solids of sunlight, it can penetrate a depth of tens of meters. When the ultrasonic wave hits the impurities or the interface, it will produce a significant reflection to form the reflection of the echo. When it hits the moving object, it can produce the doppler effect. Sensors based on ultrasonic characteristics are called "ultrasonic sensors" and are widely used in industry, defense, and biomedicine.

However, since the curie point of piezoelectric materials is usually very high, especially the ultrasonic distance sensor module used for diagnosis uses a small ultrasonic power, the operating temperature is relatively low, and it can work for a long time. Medical ultrasound probes are relatively hot and require separate refrigeration equipment. Sensitivity mainly depends on the manufacturing of the wafer itself. The electromechanical coupling coefficient is large and the sensitivity is high; on the contrary, the sensitivity is very low. There are three reasons:

1. The current frequency ultrasonic sensor is relatively fixed. For example, a 40KHz sensor can only be used for 38-42KHz. Other frequencies are similar. At present, there are almost no sensors in a wide frequency range, such as products from 40KHz to 500KHz;

2. The driving voltage is very high, usually between 100Vp-p and 1500Vp-p. Many low-voltage devices require pulse transformer boost, but it will bring some complicated problems. If there is a 3~5V low voltage drive (more power), the ultrasonic sensor is better;

3. The sensitivity is preferably higher; it can be seen that the ultrasonic module distance measuring sensor can transmit, receive and analyze the sound that cannot be detected by the human ear. In the detection of ultrasonic sensors, it can be used to achieve functions such as ultrasonic ranging and ultrasonic testing. It can be used to detect submarine wrecks, enemy submarines, and display metal internal damage. These can be applied to industry, agriculture, light industry and medical technology, and are closely related to our lives.

Why use ultrasonic sensors?

Ultrasound is reliable in any lighting environment and can be used indoors or outdoors. Ultrasonic sensors can handle robots to avoid collisions and move as soon as they are not too fast. Ultrasonic sensors are widely used and can be reliably used in grain tank sensing applications, water level sensing, drone applications and local direct restaurant or bank sensor cars. Ultrasonic rangefinders are often used as a means of detecting collisions.