Abstract

The bi-directional visitors counter is developed to know the total number of visitors present in a room at any specific time. This counter will use the simple calculator instead of a counter-and display circuit. Here, the calculator is used as a normal calculator. This visitors counter is very helpful for the places like buildings, offices and movie theatres. All the components are easily available in the market and we can build the circuit easily.

Circuit Description

Here, two transmitter-receiver pairs are used at the passage. One pair is at the entry side of the passage and it contains the light source A (transmitter) and light -dependent resistor LDR1 (receiver). Another pair is installed at the exit side of the passage and it contains the light source B (transmitter) and LDR2 (receiver). The light from light sources (torches) must continuously fall on the respective light dependent resistors (LDRs). Hence, the proper orientation of light beams and LDRs is very essential.