I'm building my own ultrasonic ranger so I don't have to pay the ridiculous prices for devices like Ping))). So far I got the transmitting part working (it produces 40khz I checked on a scope). The receiving part is giving me some trouble, I don't understand analog very well circuits so bear with me, I used a basic mic pre-amp circuit (here:http://schematics.circuitdiagram.net/images/viu1261279341a.jpg
) with an ultrasonic transducer and tried reading it with my arduino analog pins and it doesn't seem to react to the ultrasonic noises. Does anybody have any idea how I can listen for ultrasonic frequencies using my transducer (040k2)? If I can somehow amplify my signal with an hbridge then that would be great cuz i'm already using half of a quad h-bridge ic (sn754410) for my transmitter.