Digital Object Counter

DIGITAL OBJECT COUNTER

Digital Object Counter


ABSTRACT

As automation is the next leading step in changing the traditional techniques, the means of

making these changes possible is currently in trend. Automating the whole system not only

reduces time, but it also saves a lot of resources and man-power. Just assume if a company

has a worker employed only for counting the finished products and if this worker is replaced

by a digital automatic system, then the chances of false counting, errors, etc. factors are

reduced. The digital system can be made with precision and high accuracy along with a high

efficiency. It thus replaces the man-power used for the simple task and thereby reduces the

problems the normal employee may create.

The techniques of developing such a system which replaces the old traditional method of

counting objects, are vivid. The developer has to take care of the nature and the environment

for which he will be creating such system. One such system which has been designed or

forecasted has been introduced in quite a few areas.

The Digital Object Counter using LDR (Light Dependent Resistor) is a simple system which

can be made into use for counting objects in the product manufacturing area of an industry,

etc. Two IC555 are used in Monostable and Astable mode for respective pulse generation.

The counter IC7490 is a decade counter which is used for generating the 0-9 BCD code. The

IC7447 is used for driving the 7 Segment Display as it is a BCD to 7 Segment Display.

As the light is blocked, a pulse is generated and given to the decade counter. It increments

and generates the code and the number is displayed on the 7 segment display.

This constitutes the whole Digital Object Counter system and is a very low cost and effective

product.

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INTRODUCTION

The digital object counter is a cost effective and a simple system. It overcomes the problem

of manual counting of objects.

Everything is digital, so the signals can be used for further analysis and is compatible with

other digital devices. If this system is implemented, then automation in the product counting

can be achieved.

Also, there is no hazardous elements used in the circuitry and hence it can be used even at

hazardous atmospheres in an industrial area.

The very basic use of IC7490 decade counter plays the main role of generating the BCD

count signals as per the input given. Timer IC555 are used in Monostable mode and Astable

mode for providing the pulses as per the input from the LDR.

The LDR detects the blockage of light and gives the equivalent triggering voltage to the

monostable multivibrator.

The generated pulse is given to the astable multivibrator as a triggering pulse and this

completes the circuit of clock generation for the decade counter IC7490.

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BLOCK DIAGRAM

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Counted Output

Power Supply

Monostable Multivibrator

(IC 555)

Astable Multivibrator

(IC 555)

BCD to 7 Segment

Display

(IC 7447)

Decade Counter

(IC 7490)

7 Segment Display

LightLDR


BLOCK DIAGRAM DESCRIPTION

As per the block diagram –

Power Supply: It is a 6V DC battery used to provide the Vcc supply to the ICs.

LDR: Light Dependent Resistors are used for sensing the light intensity.

Monostable Multivibrator: IC555 is used in monostable mode for providing the initial pulse.

Astable Multivibrator: IC555 is used in astable mode for generating the clocking signals for the

decade counter IC.

Decade Counter: IC7490 is a decade counter which counts from 0-9 and provides BCD output.

BCD to 7 Segment Display: IC7447 is used to convert the BCD signals into the equivalent 7 segment

display signals.

7 Segment Display: Used to display the number of counts.

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CIRCUIT DIAGRAM

As per the circuit diagram, the LDR receives the light signal and acts accordingly. Whenever

there is light blockage, the resistance increases and the triggering signal is given to the

monostable multivibrator.

The monostable mutivibrator generates a high signal which activates the astable

multivibrator. This astable multivibrator and the other resistors provide the clocking

frequency for the decade counter.

The decade counter IC7490 starts counting the signals and provides the BCD equivalent

output.

This BCD output is given to the seven segment display and it thus displays the equivalent

counts.

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COMPONENTS USED

1. Resistors - 1kΩ, 330Ω, 100kΩ, 47kΩ

2. Capacitors – 0.01uF, 10uF

3. Light Dependent Resistor (LDR)

4. 6V Battery

5. Timer IC555 (2)

6. Decade Counter IC7490

7. BCD to 7 Segment Display IC7447

8. 7 Segment Display

DECADE COUNTER IC7490

IC 7490 is a decade counter which drives input by 10 and provides BCD outputs 0 to 9, this is

also called as decimal counter. This counter comprises of a divide-by 2 and divide-by 5

counters. To use as decade counter we have to cascade divide-by 2 and divide-by 5. Outputs

Q0 to Q3 are BCD outputs, inputs A and B are clock inputs to the, divide-by 2 and divide-by

5 counters respectively. R01 and R02 are the reset inputs, when these are activated counter

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output goes to 0000. S91 and S92 are the set inputs to the counter, when these inputs are

activated counter output goes to 1001.

REFERENCE

[1] http://www.circuitstoday.com/555-timer-as-monostable-multivibrator

[2] http://www.circuitstoday.com/555-timer-as-an-astable-multivibrator

[3] http://en.wikipedia.org/wiki/Light_Dependent_Resistor

[4] http://www.datasheetarchive.com/IC+7490-datasheet.html

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Digital Object Counter

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