This is a video tutorial of ultrasonic security. This tutorial explains how ultrasonic security circuit works. The ultrasonic security circuit consist of two main circuit. First is a transmitter circuit which transmit the ultrasonic signal. And then a receiver circuit, it is used to receive signal from the transmitter. The front of receiver circuit is a signal receptor and the back is programed LED. Here is the video tutorial:
On the receiver there are 2 main programs, program A and program B. Program A, the alarm will beep five times when there is an object between transmitter and the receiver. If we use program B, when there is object between the receiver and transmitter, the alarm will beep until we stop it by pressing the button. So when the thief pass the ultrasonic security, the alarm will beep.