Ultrasonic range finder for reflection free operation - has separate remote transmitter triggered from receiver via transmission link

摘要

The ultrasonic range-finder reduces errors due to multiple-path reflections, and comprises separate transmit and receive units - placed at either limit of the distance being measured. The receiver unit comprises an ultrasonic detector (UE) whose output is connected to a measuring circuit. The time delay measured is proportional to distance and is displayed in a suitable form (F). A trigger pulse from a 'press-to-measure' button (T) is sent to an ultrasonic transmitter (US) at the remote location. The transmitter can be triggered by cable, light beam or radio link. The trigger pulse also starts the timing circuit (M). The timing sequence is stopped on receipt of the ultrasonic signal from the remote transmitter.