The 40KHz high-frequency voltage is applied to the piezoelectric ceramic (double crystal oscillator) with a resonant frequency of 40KHz in the transmitting sensor the piezoelectric ceramic chip is based on the added high-frequency voltage polarity elongation and shorten, so send 40KHz frequency ultrasonic wave, its ultrasonic in density form transmission (the degree of density can be modulated by the control circuit), and passed to the wave receiver.
The receiver is the use of pressure sensors using the principle of piezoelectric, that is, pressure on the piezoelectric elements, so that the piezoelectric elements of the strain, then produce a "+" pole, the other side of the "-" pole of the 40KHz sine voltage. Because the high frequency voltage amplitude is small, it must be enlarged. The ultrasonic sensor allows the driver to reverse safely, using the principle of detecting any obstructions that exist on or near the reversing path and issuing warnings in a timely manner. The Designed detection system can provide both audible and visual warnings of sound and light, and the warning indicates that the distance and direction of obstructions in the blind zone are detected. In this way, in a narrow place whether it is parking or driving, with the help of reversing the alarm detection system, the driver's psychological pressure will be reduced, and can easily take the necessary action.