literature survey bidirectional visitor counter project report

literature survey bidirectional visitor counter project report

This article describes the design and working of a bidirectional visitor counter. The main intention is to design a system wherein the number of persons entering or leaving a room is displayed on a screen. When a person enters the room, count would be increased, whereas on leaving, the count would decrease. IR sensing mechanism is used to sense the presence of visitors and the whole counting operation is done by a microcontroller. But, before going to know about this circuit, get an idea about how to interface a 7 segment LED Display to 8051 Microcontroller as we use use this concept in this project.

Bidirectional Visitor Counter Circuit Principle:

The circuit works on the principle of IR sensing. Two sets of IR sensors consisting of an IR LED and photo transistor are placed at two ends. Output from each sensor is fed to the microcontroller. In normal operation, IR light from the LED would fall on the photo transistor and the latter would conduct. The output from the sensor would be a logic low signal in this case. In case of any interruption (due to any person crossing the path), the photo transistor would cease to conduct or conduct less and the output from the sensor would be a logic high signal. The transition from low to high, for each sensor pair is detected by the microcontroller and accordingly the count would be increased or decreased.