I've taken apart an old range finder (see photo here). It uses a circular, seemingly gold-plated, two-wire sensor that I'd like to re-use in an Arduino project. I'm looking for a datasheet of the sensor and/or a circuit-diagram. Any help is welcome.
The big circular parts likely is ultrasonic transducer as used in instant camera.
Working principle is same as modern unit, easily available at a few US dollars. The transducer does NOT work by itself, needs the associate PCB to work.