Hi! I would just like to ask help for a project. I want to make a ultrasonic parking sensor. I saw a transmitter from http://ecelab.com/circuit-ultrasonic-t.htm.

For the receiver part, I'm having difficulty designing the circuit. I want the driver to hear beeps when the obstruction is near. The closer the distance the higher the frequency of the beeps. I've read that it could be done using voltage to frequency converters, but I'm not sure how to connect them to the speaker. Furthermore I need to use op-amps for this. Does anyone have a schematic diagram that I can study? Or does anyone have an idea on how I can implement it using op-amps? Thanks in advance!

 

Have a look through these links, there are several receivers. Choose one and ask for details if needed.

http://www.discovercircuits.com/U/ultrasonic.htm