Microcontroller-bAsed bidirectionAl Visitor counter
UMAR SUNIL K
AkshAy MAthur, kuldeep singh nAglA
isitor counting is simply a measurement of the visitor traffic entering and exiting offices, malls, sports venues, etc. Counting the visitors helps to maximise the efficiency and effectiveness of employees, floor area and sales potential of an organisation. Visitor counting is not limited to Semiconductors: IC1 - LM324 quad op-amp IC2 - 74LS76 J-K flip-flop IC3 - AT89C52 microcontroller IC4 - 7805 5V regulator T1, T2 - L14F1 npn phototransistor T3, T4 - 2N3904 npn transistor IR TX1, IR TX2 - IR transmitting LED BR1 - 1A bridge rectifier DIS1-DIS3 - LTS543 CC 7-segment display Resistors (all ¼-watt, ±5% carbon): R1, R2 - 68-ohm R3, R4 - 6.8-kilo-ohm R5, R6 - 100-ohm R7, R8, R10, R11 - 10-kilo-ohm R9 - 4.7-kilo-ohm R12-R32 - 220-ohm VR1, VR2 - 20-kilo-ohm preset RNW1 - 10-kilo-ohm resistor network Capacitors: C1, C2 C3, C4 C5 C6 C7 Miscellaneous: XTAL X1 S1 S2 - 0.2µF ceramic disk - 33pF ceramic disk - 10µF, 16V electrolytic - 470µF, 25V electrolytic - 0.1µF ceramic disk - 12MHz crystal - 230V primary to 7.5V, 250mA secondary transformer - Push-to-on switch - On/off switch
Fig. 1: Transmitter-receiver set-up at the entrance-cum-exit of the passage
the entry/exit point of a company but has a wide range of applications that provide information to management on the volume and flow of people throughout a location. A primary method for counting the visitors involves hiring human auditors to stand and manually tally the number of visitors who pass by a certain location. But human-based data collection comes at great expense. Here is a low-cost microcontrollerbased visitor counter that can be used to know the number of persons at a place. All the components required are readily available in the market and the circuit is easy to build. Two IR transmitter-receiver pairs are used at the passage: one pair comprising IR transmitter...