i want to build my own ultrasonic range finder

[hussong1555]

build ultrasonic range finder

i want to use an ultrasonic range finder similar to the parallax one for a robot i am working on for my final college project. the problem is i don't want to pay $30 each for the range finders. does anyone know where i could find a schematic to build myself. Any assistance would be greatly appreciated. thanks

 

[daifeili]

build own ultrasonic range

you may try yourself

 

[Faizan Jawaid]

Try this...

Its a little tough but u have the will u have the way...First take a speaker. Connect it to a 5vpp 30KHz square wave generator. Then take another speaker. Put a mV meter to its terminals and notice voltage change as go go further. See pic attached. Speaker must be small so that it can vibrate at high frequency....Experiment it....