Microchip Technology

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Company Logo Microchip

  • Bidirectional Visitor Counter

  • Created: Oct 02, 2014

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This project uses Microchip's SST89E516RD-40-C-PIE microcontroller that serves as a people counter. A people counter is a device used to measure the number of people traversing a certain passage and is often used at the entrance/exit of a building so that the total number of visitors can be recorded. It ensures a safe and comfortable setting for patrons entering banks, restaurants, hospitals, leisure centers, and sports stadiums.

The circuit works on the principle of IR sensing. Two sets of IR sensors consisting of an IR LED and phototransistor 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 phototransistor 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 phototransistor would cease to conduct or conduct less and the output from the sensor would be 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.

This circuit works in a two-way direction, that means the counter will be incremented if person enters the room and will be decremented if a person leaves the room then displays the total count on the screen. It can be used domestically to get an indication of number of persons entering and leaving a party, meetings, etc. It can also be used as home automation system to ensure energy saving by switching on the loads and fans only when needed.



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