current status of ultrasonic distance sensors

A device for transmitting and receiving ultrasonic waves, which is called an ultrasonic transducer or ultrasonic probe; an ultrasonic transducer and transceiver circuit constitutes an ultrasonic sensor. In order to develop a large-range ultrasonic sensor, it is necessary to understand the physical properties of ultrasonic waves and the development of ultrasonic transducer technology. The propagation of vibration in an elastic medium is called wave, referred to as wave. A mechanical wave with a vibration frequency is between 16 kHz and 20 kHz can be heard by the human ear and called a sound wave; a mechanical wave is below 16 kHz is called an infrasound wave; a mechanical wave is higher than 20 kHz called depth sensor acoustic transducer and a mechanical wave is higher than 100 MHz is a mechanical wave. It is called special ultrasonic wave. Like other sound waves, the propagation speed of ultrasonic waves depends on the density of the medium and the elastic constant of the medium. Under the atmospheric conditions, the propagation speed of ultrasonic waves in the same medium is the same and in a relatively large frequency range, the speed of sound is solid.

The sound wave propagates due to the motion of the particle in the propagation medium, and its propagation direction is consistent with its vibration direction, so the sound wave in the air belongs to the elastic mechanical wave of the longitudinal vibration. In the ideal medium, the equation motion of a particle displacement is describing the propagation of a ultrasonic distance measuring transducer in the positive direction of x can be expressed.

  For example, when the vibration frequency of the ultrasonic wave is 30 kHz, the physical meaning is ultrasonic waves in the air.When the medium propagates, the energy is absorbed and lost. When the propagation distance of the sound wave is equal to 1/a, the amplitude of the ultrasonic range finding sensor will be attenuated to 1/e times the initial value. Obviously, the higher is the acoustic wave frequency, the greater is the absorption and attenuation of the acoustic energy, and the smaller propagation distance is the acoustic wave. Conversely, the lower is the acoustic frequency, the smaller is the absorption attenuation of the acoustic energy, and the greater is the propagation distance of the acoustic wave. Perhaps it is the true portrayal of the low frequency music that reverberates and lasts for a long time. Another important property of sound waves is that the higher the frequency of the wave, the stronger is directional propagation of sound waves (or linear motion) and the ability to reflect, and the energy is much larger than the low-frequency sound waves of the same amplitude.