Object counter using LDR and calculator

To make an object counter we can use a simple dark detector circuit and a normal calculator. Pole and NO (Normally Open) terminals of a relay have to be connected to the two pins which are used to activate ‘=’ key of calculator.
As we block the light falling on LDR, the calculator starts counting.
For the calculator to work as a counter, we first need to press ‘1’ and ‘+’ keys.

All calculators may not work as counter, you need to check with the following steps:

a. First press 1

b. Then Press +

c. Then keep on pressing =

Each time when you press “=”, the calculator should increase the numbers and display 1,2,3,4… and so on. If your calculator displays “1″ every time you press “=”, then your calculator cannot be used as counter.

In our circuit, we use relay to connect two wires of ‘=’ key that eventually increases numbers on calculator.

TESTED and VERIFIED

We have recently released a 3 digit digital object counter kit. You can buy the kit at BuildCircuit store. 

  • 3 Digit Digital Object Counter ASSEMBLED Kit With Infrared Transmitter And Laser Module

    US $14.95
    12 items sold

    3 Digit Digital Object Counter ASSEMBLED Kit With Infrared Transmitter And Laser Module

    US $14.95
    12 items sold

    This is 3 digits digital object counter kit for electronics beginners and hobbyists. It is the upgraded version of our previous 2 digits and 3 digits object counter.

    You can use this 3 digits digital object counter for counting objects or people entering in a room. It can be used by engineers for learning about digital counters.

    This DIY digital object counter works with VS1838 infrared receiver and photoresistor and there are three seven segment displays displaying numbers from 0 to 999. An IR transmitter is directed towards the VS1838 infrared receiver of the counter module and objects are moved between the two modules. Each time an object passes between the two modules, the seven-segment displays show increment in numbers from 0 to 999.

    45 in stock

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  • 1.8″ Photoresistor And Laser Operated Medium Digital Objects Counter

    US $19.95
    13 items sold

    1.8″ Photoresistor And Laser Operated Medium Digital Objects Counter

    US $19.95
    13 items sold

    This is an upgraded version of the previous digital objects counter kit. The device has 1.8″ common cathode seven segment displays.

    The kit is based on the CD4026 decade counter.

    4 in stock

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  • 2.3″ Common Anode Seven Segment Display Driver

    US $13.95
    8 items sold

    2.3″ Common Anode Seven Segment Display Driver

    US $13.95
    8 items sold

    This is a 74LS192 based up and down counter driver module for driving 2.3 inches seven segment display. The module has headers on two sides to receive up/down count signals and to concatenate with another driver module.

    The module can be triggered with NE555, flashing LED, and Arduino. It can also be triggered by anything that generates a clock pulse.

    10 in stock

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  • 2.3″ common cathode seven segment display driver

    US $11.95US $12.95
    22 items sold

    2.3″ common cathode seven segment display driver

    US $11.95US $12.95
    22 items sold

    This is a CD4026 based up counter driver module for driving 2.3 inches common cathode seven segment display. The module has headers on two sides to receive up count signals and to concatenate with another driver module.

    The module can be triggered with NE555, flashing LED, and Arduino. It can also be triggered by anything that generates a clock pulse.

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  • CD4026- 1 Digit Up Counter Module

    US $4.95
    65 items sold

    CD4026- 1 Digit Up Counter Module

    US $4.95
    65 items sold
    • It works as an UP counter. You can instantly test the up count of the display using a flashing LED.
    • It is a handy tester for 0.56″ seven segments common cathode display.
    • Works with Arduino or NE55 or whatever that gives pulse.
    • You can concatenate as many displays as you want.
    • With this, you can build your own digital objects counter.
    • Size: 15mmx49mm

    50 in stock

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  • CD4029 Based Up And Down Counter For Arduino And NE555

    US $7.95
    21 items sold

    CD4029 Based Up And Down Counter For Arduino And NE555

    US $7.95
    21 items sold

    50 in stock

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  • Photoresistor And Laser Operated Large Digital Objects Counter With 2.3″ Displays

    US $29.95
    9 items sold

    Photoresistor And Laser Operated Large Digital Objects Counter With 2.3″ Displays

    US $29.95
    9 items sold

    A laser light module illuminates the photoresistor continuously and whenever any object obstructs the laser light falling on the photoresistor, the counter increases the count. You can use this 3 digit digital objects counter for counting objects or people entering a room. It can be used by engineers for learning about digital counters.

    4 in stock

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