reveiw on visitor counter using atmega328
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Two-way visitor counter based on microcontrollers and designed and presented to count visitors to an auditorium, room, offices, shopping centers, sports venues, etc. The system counts both the incoming and outgoing visitor of the auditorium or room or other place where it is placed.
A counter that can change its state in any direction, under the control of an ascending selector input, is known as an up counter. The circuit given here can count numbers from 0 to 9999 in up and down modes depending on the state of the selector. It can be used to count the number of people entering a room in the upstairs mode at the front door. In the descent mode, you can count the number of people leaving the room reducing the count at the exit door. It can also be used on the doors of parking areas and other public places.
This circuit is divided into three parts: sensor, controller and counter. The sensor would observe an interruption and provide an input to the controller that would operate the counter in up / down mode depending on the setting of the selector. The same count is displayed on a set of 7-segment displays through the controller.
The circuit operates according to the principle of IR detection. Two sets of IR sensors consisting of an IR LED and a phototransistor are placed at two ends. The output of each sensor is fed to the microcontroller. In normal operation, the infrared LED light would fall on the phototransistor and this would act. The sensor output would be a low logic signal in this case. In case of any interruption (due to any person crossing the road), the phototransistor would stop driving or drive less and the sensor output would be a high logic signal. The low-to-high transition for each pair of sensors is detected by the microcontroller and, as a result, the count will increase or decrease.
Diagram is given below: