Automatic counting system for passages

摘要

The invention is particularly useful for counting the passengers moving into and out of a common carrier vehicle such as a motor bus. Three ultrasonic ranging stations are provided to determine the presence and absence of passengers at three successive positions at the bus entrance. The three positions may correspond respectively to three steps through the entrance. Sequence logic circuitry is included for analyzing the sequence of detection of passengers at the three different ranging stations to establish a count of the number of passengers entering or leaving.