A Bi-directional Visitors Counter | Electrical Project
A Bi-directional Visitors Counter
Abstract
This counter can be used to know the number of visitors
present in the room at any given time. It is useful for places such as movie
halls, buldings and offices. To keep the cost low it uses simple calculator
instead of a counter-and display circuit. The calculator can be used as a
normal calculator is plugging it off from the circuit. All the components are
readily available in market and the circuit is easy to build.
Circuit description
Two transmitter-receiver pairs are used at the passage: One
pair comprising light source A (transmitter) and light -dependent resistor LDR1
(receiver) is installed at the entry side of the passage, while the other pair
comprising light source B (transmitter) and LDR2 (receiver) is installed exit
side of the passage. Light from. two light sources (torches) should
continuously fall on the respective light dependent resistors (LDRs), so proper
orientation of light beams and LDRs is essential.
