05-05-2011, 10:15 AM
Visitor counting is simply ameasurement of the visitortraffic entering and exitingoffices, malls, sports venues, etc.Counting the visitors helps to maximisethe efficiency and effectiveness ofemployees, floor area and sales potentialof an organisation.Visitor counting is not limited to the entry/exit point of a company buthas a wide range of applications thatprovide information to managementon the volume and flow of peoplethroughout a location. A primarymethod for counting the visitors involveshiring human auditors to standand manually tally the number of visitorswho pass by a certain location. Buthuman-based data collection comes atgreat expense.Here is a low-cost microcontrollerbasedvisitor counter that can be usedto know the number of persons at aplace. All the components required arereadily available in the market and thecircuit is easy to build.Two IR transmitter-receiver pairsare used at the passage: one paircomprising IR transmitter IR TX1 andreceiver phototransistor T1 is installedat the entry point of the passage, whilethe other pair comprising IR transmitterIR TX2 and phototransistor T2 isinstalled at the exit of the passage. TheIR signals from the IR LEDs shouldcontinuously fall on the respectivephototransistors, so proper orientationof the transmitters and phototransistorsis necessary.Circuit descriptionFig. 1 shows the transmitter-receiverset-up at the entrance-cum-exit of theSUNIL KUMAR
Visitor counting is simply ameasurement of the visitortraffic entering and exitingoffices, malls, sports venues, etc.Counting the visitors helps to maximisethe efficiency and effectiveness ofemployees, floor area and sales potentialof an organisation.Visitor counting is not limited to passage along with block diagram.Two similar sections detect interruptionof the IR beam and generate clockpulse for the microcontroller. Themicrocontroller controls counting anddisplays the number of persons presentinside the hall.Fig. 2 shows the circuit of themicrocontroller-based visitor counter,wherein the transmitter and thereceiver form the IR detection circuit.Control logic is built around transistors,operational amplifier LM324 (IC1)and flip-flop (IC2).When nobody is passing throughthe entry/exit point, the IR beamcontinuously falls on phototransistorT1. Phototransistor T1 conducts andthe high voltage at its emitter drivestransistor T3 into saturation, whichmakes pin 3 of comparator N1 low andfinally output pin 1 of comparator N1is high.Now if someone enters the place,first the IR beam from IR TX1 is interruptedand then the IR beam from IRTX2. When the beam from IR TX1 isinterrupted, phototransistor T1 andtransistor T3 cut-off and pin 3 of comparatorN1 goes high.
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