Ultrasonic ranging circuit

Shown is the ultrasonic transmitting/receiving ranging circuit , which is played by the same ultrasonic transducer and its operating frequency is 40kHz. The sending
and receiving status is controlled by the time base circuit 555. Adding a 1N4007 diode to the circuit can shorten the sending ultrasonic time and
lengthen the receiving time. The square wave output from pin ③ of the 555 circuit is sent to I through the lOkfl resistor. Pin ⑧ of M1812, the received signal is coupled
to I by capacitor G. The ④ pin of M1812, the detection signal is output from the @ pin. The ranging range is 0~6m.