ultrasonic sensor interface

[contact.vpb]

Hi
i have a problem with ultrasonic sensors . I am using it for measuring the angle made by transmitter with a know reference .The receiver gives a an output of 250mv when it receives ultrasonic rays and 100mv when no rays are received .But i can measure this variation only when i have kept the multimeter in AC mode not in DC mode . I would like to know a circuit which can differentiate these two.
please reply immediately.
praveen babu

 

[banh]

hi,

what is the ultrasonic device you are using?

 

[centiago]

Make sure your PCB designed has seperation between the transmit & receive section.
If you sould attach screenshot of your circuit, we can look & comment on same. Difficult to guess.