A Bidirectional Visitor Counter using AVR ATmega16

This counter system built using AVR ATmega16 can be used to count objects passing in a converyer belt or peoples entering of leaving a room. It is bidirectional, that means if a person enter the room, it will increment the count and if a person leaves the room then it will decrement the counter. The count is displayed in a 3 digit seven segment display. Object or visitor is sensed using IR sensors. On one side we place an IR led that emits invisible IR rays. These rays are incident on ir sensors placed on the opposite side. When IR rays are freely falling on the sensors, the output of the sensor is LOW (that is close to 0v) and when any obstacle comes between the IR LEDs and the sensors, the rays cannot reach the sensor, thus making the output of IR sensor go HIGH(close to 5v).”