In Reply to: Ultrasonic Sensor for obstacle detection posted by Tara on 02/24/01 at 4:30 PM:
Greetings. I have a simple circuit which allows a 40KHz feed to a transducer which, when aimed at a second similar transducer/amplifier will act as an "obstacle detector". The original design was used for detecting a "film-out" condition in a high speed rewinder, since the usual I.R. system would trigger on clear portions of the film.
I would be happy you forward a copy of the circuit if you are still interested.
Brian Snell (email@example.com)