Course photoelectric counting

Design title : Light-controlled counter

1. Tasks and Requirements

Design a circuit that uses the on and off of light to count the number of people entering the laboratory. Specific requirements are as follows:

1. Basic requirements

1)  Design two light control circuits, one is placed outside the door, and the other is set inside the door, when someone passes through the door (whether entering or leaving the room). One light control circuit will be triggered first, and then another light control circuit will be triggered. It is required to determine whether a person enters or leaves the laboratory based on the sequence in which the light control circuit generates trigger pulses. When someone enters the laboratory, the counter counts up, and when someone leaves the laboratory, the counter counts down.

2)  The maximum counting capacity of the counter is required to be 99, and a digital tube is used to display the numbers.

2. Play part

1)  It has manual reset and clear function.

2)  It is required that the LED indicator light flashes once (or the buzzer sounds once) every time the counter counts a number.