Object counter

object counter using LDR

1. OBJECT COUNTER

ABSTRACT
Counters with bidirectional detection are useful for counting of objects moving along a
predefined path. These may find applications as visitor counters and also for counting of objects.
Here we present a simple circuit that counts the number of objects entering the premises.

2. OBJECT COUNTER

CONTENTS:
TOPICS
INTRODUCTION
COMPONENTS REQUIRED
BLOCK DIAGRAM
CIRCUIT DIAGRAM
WORKING PRINCIPLE
APPLICATIONS
DRAWBACK
CONCLUSION
REFERENCE

3. OBJECT COUNTER

INTRODUCTION:
Object counter is a device which is designed to count the object which passing from above it or
by touching it. But main work of object counter is the counting of object or things. It can be done
by using LDR, THERMISTORS, VDR.
These are used for sensing that a object is arrive or present here. Important materials used in
building object counter is seven segment decoder (7447 IC), 741 op-amp, LDR, BCD counter
(4510), seven segment display with common anode.
741 IC is most important device that is used in object counter. It was designed by “DAVE
FULLAGAR” of Fairchild semiconductor in 1968. 741 IC is available in the market as 8 pin
metal, 10 pin flat-pack, 8 or 14 pin DIP.
The maximum rating of IC voltage, input and differential input voltage, storage and operating
temperature and short circuit duration. The manufacturers advice not to exceed these maximum
ratings even under the worst operating conditions.
COMPONENTS REQUIRED:
 4510 IC(BCD Counter)
 7447 IC(7 Segment decoder)
 741(op-amp)
 LDR(light dependent resistor)
 Potentiometer(100kΩ)
 10kΩ resistor
 470Ω resistor
 7 segment display with common anode
 White LED

4. OBJECT COUNTER

BLOCK DIAGRAM:







Input comprises of sensors which is taken from physical world. In this LDR is used as a sensor
which is analog in nature. The signal from input is fed to the processor part which comprises of
4510 BCD counter. Since we are using LDR which is analog but the signal is converted to digital
when we are giving it to processor. The output is displayed on 7 segment LED when the object is
sensed.


CIRCUIT DIAGRAM:



INPUT STAGE


PROCESSING
STAGE


OUTPUT STAGE

5. OBJECT COUNTER

WORKING PRINCIPLE:
INPUT PART
The op-amp used in input acts as a comparator. Considering the equation V0=A[V+-V-]. Where
‘A’ is high gain factor. If we give reference voltage to inverting input terminal and input voltage
to non inverting input terminal of op-amp then output voltageV0=[Vin-vref].
The op-amp as comparator we are used to compare the input voltage to reference voltage. Op-
amp is considered as linear and it is less affected to noise. Considering the negative voltage
supply as zero potential and positive supply as one we will get the logic as follows
Vin > Vref 1
Vin < Vref 0
We are using potentiometer that is variable resistor feeding to negative terminal of op-amp.
Output from LDR is fed to positive terminal of op-amp. It is used as potential divider and its
resistance depends upon the relative rotation of variable resistor. In half rotation of potentiometer
the resistance will be R=50KΩ and reference voltage becomes
Vref =(50KΩ/100KΩ)*5=2.5V
PROCESSOR:
The main part of the processing circuit is 4510 IC. It is 16 pin DIP IC. The first pin of this IC is
preset enable, until or unless it has zero input inserted till then the whole IC will be functioning
otherwise if it is given 1 then it goes to the preset value. If we want to count the input we need to
give zero to carry input(CT).
When signal from input is given to the processor part, preset enable, clock input and reset must
be given to ground. UP/DOWN counter must be given high because we are counting numbers
from 0 to 9.
OUTPUT:
The output consists of 7 segment LED. To drive this LED we need a decoder. Since we are using
common anode 7 segment display i.e, 7447 IC. The output of 4510 IC is fed to the 7447 IC QA
is fed to A, QB is fed to B, QC is fed to C, and QD is fed to D. When LDR is disturbed by
moving object so it senses the object and count is made on 7 segment display. Hence we can
count the object passing through it.

6. OBJECT COUNTER

APPLICATIONS:

 Object counter used in counting the products passing through an assembly line in a
manufacturing plant.
 Count the number of people entering a restaurant.
 It is used in banks for counting the number notes.
 It is also used in airports, car parking systems etc




DRAWBACK:
 Whenever two same object pass at a same time object counter consider only one count..


CONCLUSION:
Analogue electronics components were investigated and a op amp, a LDR, a
BCD counter, a BCD Decoder and a seven segment display were combined to form a
digital counter circuit. Different methods were analysed to determine the best technique
for creating an efficient counter circuit simple one was chosen and the circuit was
designed. The chosen circuit was verified through simulation using proteous . This design
was then implemented and modified to suit the needs of the project. Problems were
analysed and repaired where necessary until it was concluded that the circuit had met the
design criteria of the project.

7. OBJECT COUNTER




COST ESTIMATION:
COMPONENTS QUANTITY COST
1. 4510 IC 1 18/-
2. 7447 IC 1 40/-
3. 741 IC 1 10/-
4. LDR 1 18/
5. POTENTIOMETER 1 10/-
6. 10KΩ RESISTOR 1 1/-
7. 470Ω RESISTOR 2 2/-
8. 7 SEGMENT DISPLAY 1 15/-
9. WHITE LED 2 4/-

8. OBJECT COUNTER




REFERENCE:
 Phillips, BCD to 7 segment Decoder, Unknown. Retrieved from
http://www.doctronics.co.uk/4511.htm
 Phillips, BCD Up/Down Counter, Unknown. Retrieved from
http://www.doctronics.co.uk/4510.htm
 Unknown, Analogue Electronics, 2006. Retrieved from
en.wikipedia.org/wiki/Analogue_electronics