Minor Project File

8/2/2019 Minor Project File

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LIGHT FENCE

SESSION 2009-10

A Minor Project Report

Submitted to

Rajiv Gandhi Proudyogiki Vishwavidyalaya

Bhopal (M.P.)

In partial fulfilment of awarding the degree of

Bachelor of Engineering

In

Electronics & Communication

Guided by: Submitted by:

Prof. Saurabh Gaur Abhishek jain

Electronics & Communication Ankit singh somvanshi

MIT, Ujjain (M.P.) Chitrarth gautam

Kamal singh rajawat

Department of electronics & communication

MAHAKAL INSTITUTE OF TECHNOLOGY ,UJJAIN


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MAHAKAL INSTITUTE OF TECHNOLOGY,

UJJAIN (M.P.)

SESSION 2009-10

CERTIFICATE

This is certify that the Minor Project work of ABHISHEK JAIN ,ANKIT SINGH

SOMVANSHI ,CHITRARTH GAUTAM ,KAMAL SINGH RAJAWAT entitled

LIGHT FENCE towards partial fulfilment of the requirement for the award of the

degree of Bachelor of Engineering in Electronics & Communication Engineering.

Internal Examiner External Examiner

--------------------------- --------------------------

-

Date: Date:


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MAHAKAL INSTITTUTE OF TECHNOLOGY

ACKNOWLEDGEMENT

Concentration, dedication and application are necessary but not

sufficient to achieve a goal. They must be awarded by guidance

assistance and cooperation. I like to express my sincere gratitude

towards my report guide Prof. Saurabh Gaur, Electronics and

Communication Department for providing me eyes of knowledge.

I am thankful to Prof. Manish Berve, HOD, Electronics and

Communication for their guidance and support.

Abhishek jain

(0704EC071004)

Ankit singh somvanshi

(0704EC071009)

Chitrarth gautam(0704EC071018)

Kamal singh rajawat

(0704EC071037)


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CONTENTS

1. INTRODUCTION

2. RELEVENT THEORY OF USED COMPONENT

RESISTOR

CAPACITOR

LIGHT EMITTING DIODE (LED)

LIGHT DEPENDENT RESISTOR (LDR)

OPERATIONAL AMPLIFIER (IC 1)

555 TIMER (IC 2)

3. PRINCIPLE OF WORKING

4. DESIGN & MAKING PCB

5. APPLICATION

6. CONCLUSION

REFERENCE

APPENDIX


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INTRODUCTION

The shadow alarm circuit can sense a moving shadow in a confined area. It can be

used to protect things from theft. When somebody approaches the unit, it will give a

loud alarm to abort the attempt of theft. The circuit uses the light sensing property of

the Photo diode.

The circuit uses the light sensing property of the PIN Photodiode. The p-n junction

of the photo diode gives light current when it is forward biased. IC1 is designed as a

voltage comparator. Its non inverting input is connected to a potential divider R1

and VR. By adjusting VR, input current to pin3 can be set to a reference level. The

inverting input of IC1 is connected to a photo diode. IC CA3130 is a 15 MHz BiMOS

Operational amplifier with MOSFET inputs and bipolar output. The inputs contain

MOSFET transistors to provide very high input impedance and very low input current

as low as 10pA. It has high speed of performance and suitable for low input current

applications

This opto-sensitive circuit sounds an alarm whenever a shadow falls on it. So it can be

used at night by shopkeepers to protect the valuables in their showrooms.


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RELEVENT THEORY OF USED COMPONENT

Resister

A Resistor is a heat-dissipating element and in the electronic circuits it is

mostly used for either controlling the current in the circuit or developing a voltage

drop across it, which could be utilized for many applications. There are various types

of resistors, which can be classified according to a number of factors depending upon:

1. Material used for fabrication

2. Wattage and physical size

3. Intended application

4. Ambient temperature rating

5. Cost

fig 3.11 Resistor

Basically the resistor can be split in to the following four parts from the construction

view point.

1. Base

2. Resistance element

3. Terminals

4. Protective means

following characteristics are inherent in all resistors and may be

controlled by design considerations and choice of material i.e. Temperature co

efficient of resistance, Voltage coefficient of resistance, high frequency

characteristics, power rating, tolerance & voltage rating of resistors. Resistors may be

classified as.

1. Fixed


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2. Semi Variable

3. Variable resistor

Capacitors

The fundamental relation for the capacitance between two flat plates separated by a

dielectric material is given by:-

fig 3.12 Capacitor

Capacitor

C=0.08854KA/D

Where

C= capacitance in pf.

K= dielectric constant

A=Area per plate in square cm.

D=Distance between two plates in cm

Design of capacitor depends on the proper dielectric material with particular type of

application. The dielectric material used for capacitors may be grouped in various

classes like Mica, Glass, air, ceramic, paper, Aluminum, electrolyte etc. The value of

capacitance never remains constant. It changes with temperature, frequency and


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aging. The capacitance value marked on the capacitor strictly applies only at specified

temperature and at low frequencies.

LED (Light Emitting Diodes)

As its name implies it is a diode, which emits light when forward biased.

Charge carrier recombination takes place when electrons from the N-side cross the

junction and recombine with the holes on the P side. Electrons are in the higher

conduction band on the N side whereas holes are in the lower valence band on the P

side. During recombination, some of the energy is given up in the form of heat and

light.


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LIGHT DEPENDENT RESISTOR (LDR)

LDRs or Light Dependent Resistors are very useful especially in light/dark sensor

circuits. Normally the resistance of an LDR is very high, sometimes as high as 1000

000 ohms, but when they are illuminated with light resistance drops dramatically.

The animation opposite shows that when the torch is turned on, the resistance of the

LDR falls, allowing current to pass through it.

When the light level is low the resistance of the LDR is high. This prevents current

from flowing to the base of the transistors. Consequently the LED does not light.

However, when light shines onto the LDR its resistance falls and current flows into

the base of the first transistor and then the second transistor. The LED lights. The

preset resistor can be turned up or down to increase or decrease resistance, in this way

it can make the circuit more or less sensitive.


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OPERATIONAL AMPLIFIER (741 IC)

An operational amplifier, which is often called an op-amp, is a DC-coupled high-

gain electronic voltage amplifier with a differential input and, usually, a single-ended

output.[1] An op-amp produces an output voltage that is typically millions of times

larger than the voltage difference between its input terminals

Typically the op-amp's very large gain is controlled by negative feedback, which

largely determines the magnitude of its output ("closed-loop") voltage gain in

amplifier applications, or the transfer function required (in analog computers).

Without negative feedback, and perhaps with positive feedback for regeneration, an

op-amp essentially acts as a comparator. High input impedance at the input terminals

(ideally infinite) and low output impedance at the output terminal(s) (ideally zero) are

important typical characteristics.

Op-amps are among the most widely used electronic devices today, being used in a

vast array of consumer, industrial, and scientific devices. Many standard IC op-amps

cost only a few cents in moderate production volume; however some integrated or

hybrid operational amplifiers with special performance specifications may cost over
http://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Direct_couplinghttp://en.wikipedia.org/wiki/Gainhttp://en.wikipedia.org/wiki/Electronic_amplifierhttp://en.wikipedia.org/wiki/Operational_amplifier#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/Operational_amplifier#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/Operational_amplifier#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/Negative_feedbackhttp://en.wikipedia.org/wiki/Transfer_functionhttp://en.wikipedia.org/wiki/Analog_computershttp://en.wikipedia.org/wiki/Positive_feedbackhttp://en.wikipedia.org/wiki/Regenerative_circuithttp://en.wikipedia.org/wiki/Comparatorhttp://en.wikipedia.org/wiki/Electrical_impedancehttp://en.wikipedia.org/wiki/Electrical_impedancehttp://en.wikipedia.org/wiki/Comparatorhttp://en.wikipedia.org/wiki/Regenerative_circuithttp://en.wikipedia.org/wiki/Positive_feedbackhttp://en.wikipedia.org/wiki/Analog_computershttp://en.wikipedia.org/wiki/Transfer_functionhttp://en.wikipedia.org/wiki/Negative_feedbackhttp://en.wikipedia.org/wiki/Operational_amplifier#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/Electronic_amplifierhttp://en.wikipedia.org/wiki/Gainhttp://en.wikipedia.org/wiki/Direct_couplinghttp://en.wikipedia.org/wiki/Direct_current


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$100 US in small quantities. Op-amps sometimes come in the form of macroscopic

components, (see photo) or as integrated circuit cells; patterns that can be reprinted

several times on one chip as part of a more complex device.

The op-amp is one type ofdifferential amplifier. Other types of differential amplifierinclude the fully differential amplifier (similar to the op-amp, but with two outputs),

the instrumentation amplifier (usually built from three op-amps), the isolation

amplifier (similar to the instrumentation amplifier, but which works fine with

common-mode voltages that would destroy an ordinary op-amp), and negative

feedback amplifier (usually built from one or more op-amps and a resistive feedback

network).
http://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/Cell_(EDA)http://en.wikipedia.org/wiki/Differential_amplifierhttp://en.wikipedia.org/wiki/Fully_differential_amplifierhttp://en.wikipedia.org/wiki/Instrumentation_amplifierhttp://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/wiki/Negative_feedback_amplifierhttp://en.wikipedia.org/wiki/Negative_feedback_amplifierhttp://en.wikipedia.org/wiki/Negative_feedback_amplifierhttp://en.wikipedia.org/wiki/Negative_feedback_amplifierhttp://en.wikipedia.org/wiki/Negative_feedback_amplifierhttp://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/wiki/Isolation_amplifierhttp://en.wikipedia.org/wiki/Instrumentation_amplifierhttp://en.wikipedia.org/wiki/Fully_differential_amplifierhttp://en.wikipedia.org/wiki/Differential_amplifierhttp://en.wikipedia.org/wiki/Cell_(EDA)http://en.wikipedia.org/wiki/Integrated_circuit


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Used as Voltage Comparator

In the shadow alarm OpAmp is used as a voltage comparator.

In the fig fixed reference voltage applied to its inverting terminal & in the same

manner time varying signal voltage Vin is applied to the non inverting terminal.

When voltage Vin is less than the ref vtg output voltage in Vsat or Vee because

voltage at inverting terminal is higher than non inverting terminal in the same that

when voltage Vin is higher than the ref. voltage output voltage is Vsat or Vcc because

voltage at non inverting terminal is higher than inverting

The comparator is also known as Voltage Level Detector because derived value of ref.

voltage the input voltage level can be detected.

The diode D1 & D2 protects the Opamp from doemame due to excessive value of

input voltage.

The resistor R connected in series with Vin is used to limit the current through diode

D1 & D2 and another resistor in series with inverting terminal & Vref to reduce offset

problem.


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IC 555 TIMER

The 555 Timer IC is an integrated circuit (chip) implementing a variety oftimer and

multivibrator applications. The IC was designed by Hans R. Camenzind in 1970 and

brought to market in 1971 by Signetics (later acquired by Philips). The original name

was the SE555 (metal can)/NE555 (plastic DIP) and the part was described as "The

IC Time Machine".[1] It has been claimed that the 555 gets its name from the three

5 k resistors used in typical early implementations,[2] but Hans Camenzind has

stated that the number was arbitrary.[3]The part is still in wide use, thanks to its ease

of use, low price and good stability. As of 2003, it is estimated that 1 billion units are

manufactured every year.[3]

Depending on the manufacturer, the standard 555 package includes over 20transistors, 2 diodes and 15 resistors on a silicon chip installed in an 8-pin mini dual-

in-line package (DIP-8).[4] Variants available include the 556 (a 14-pin DIP

combining two 555s on one chip), and the 558 (a 16-pin DIP combining four slightly

modified 555s with DIS & THR connected internally, and TR falling edge sensitive

instead of level sensitive).
http://en.wikipedia.org/wiki/Integrated_circuithttp://en.wikipedia.org/wiki/Timerhttp://en.wikipedia.org/wiki/Multivibratorhttp://en.wikipedia.org/wiki/Hans_R._Camenzindhttp://en.wikipedia.org/wiki/1970http://en.wikipedia.org/wiki/1971http://en.wikipedia.org/wiki/Signeticshttp://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/DIP-8http://en.wikipedia.org/wiki/555_timer#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/555_timer#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/555_timer#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/Ohmhttp://en.wikipedia.org/wiki/Ohmhttp://en.wikipedia.org/wiki/Ohmhttp://en.wikipedia.org/wiki/555_timer#cite_note-1#cite_note-1http://en.wikipedia.org/wiki/555_timer#cite_note-1#cite_note-1http://en.wikipedia.org/wiki/555_timer#cite_note-1#cite_note-1http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/1000000000_(number)http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/DIP-8http://en.wikipedia.org/wiki/555_timer#cite_note-3#cite_note-3http://en.wikipedia.org/wiki/555_timer#cite_note-3#cite_note-3http://en.wikipedia.org/wiki/555_timer#cite_note-3#cite_note-3http://en.wikipedia.org/wiki/555_timer#cite_note-3#cite_note-3http://en.wikipedia.org/wiki/DIP-8http://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Transistorhttp://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/1000000000_(number)http://en.wikipedia.org/wiki/555_timer#cite_note-semiconductormuseum.com-2#cite_note-semiconductormuseum.com-2http://en.wikipedia.org/wiki/555_timer#cite_note-1#cite_note-1http://en.wikipedia.org/wiki/Ohmhttp://en.wikipedia.org/wiki/555_timer#cite_note-0#cite_note-0http://en.wikipedia.org/wiki/DIP-8http://en.wikipedia.org/wiki/Philipshttp://en.wikipedia.org/wiki/Signeticshttp://en.wikipedia.org/wiki/1971http://en.wikipedia.org/wiki/1970http://en.wikipedia.org/wiki/Hans_R._Camenzindhttp://en.wikipedia.org/wiki/Multivibratorhttp://en.wikipedia.org/wiki/Timerhttp://en.wikipedia.org/wiki/Integrated_circuit


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Ultra-low power versions of the 555 are also available, such as the 7555 and

TLC555.[5] The 7555 requires slightly different wiring using fewer external

components and less power.

The 555 has three operating modes:

Monostable mode: in this mode, the 555 functions as a "one-shot".

Applications include timers, missing pulse detection, bouncefree switches,

touch switches, frequency divider, capacitance measurement, pulse-width

modulation (PWM) etc

Astable - free running mode: the 555 can operate as an oscillator. Uses include

LED and lamp flashers, pulse generation, logic clocks, tone generation,

security alarms, pulse position modulation, etc.

Bistable mode or Schmitt trigger: the 555 can operate as a flip-flop, if the DIS

pin is not connected and no capacitor is used. Uses include bouncefree latched

switches, etc.

The connection of the pins is as follows:

S.No. Name Purpose

1 GND Ground, low level (0 V)

2 TRIG A short pulse high-to-low on the trigger starts the timer

3 OUT During a timing interval, the output stays at +VCC

4 RESETA timing interval can be interrupted by applying a reset pulse to low

(0 V)

5 CTRL Control voltage allows access to the internal voltage divider (2/3 VCC)
http://en.wikipedia.org/wiki/555_timer#cite_note-4#cite_note-4http://en.wikipedia.org/wiki/555_timer#cite_note-4#cite_note-4http://en.wikipedia.org/wiki/555_timer#cite_note-4#cite_note-4http://en.wikipedia.org/wiki/Monostablehttp://en.wikipedia.org/wiki/Astablehttp://en.wikipedia.org/wiki/Oscillatorhttp://en.wikipedia.org/wiki/LEDhttp://en.wikipedia.org/wiki/Pulse_position_modulationhttp://en.wikipedia.org/wiki/Bistablehttp://en.wikipedia.org/wiki/Schmitt_triggerhttp://en.wikipedia.org/wiki/Flip-flop_(electronics)http://en.wikipedia.org/wiki/Vcchttp://en.wikipedia.org/wiki/Vcchttp://en.wikipedia.org/wiki/Vcchttp://en.wikipedia.org/wiki/Vcchttp://en.wikipedia.org/wiki/Flip-flop_(electronics)http://en.wikipedia.org/wiki/Schmitt_triggerhttp://en.wikipedia.org/wiki/Bistablehttp://en.wikipedia.org/wiki/Pulse_position_modulationhttp://en.wikipedia.org/wiki/LEDhttp://en.wikipedia.org/wiki/Oscillatorhttp://en.wikipedia.org/wiki/Astablehttp://en.wikipedia.org/wiki/Monostablehttp://en.wikipedia.org/wiki/555_timer#cite_note-4#cite_note-4


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6 THRThe threshold at which the interval ends (it ends if the voltage at THR

is at least 2/3 VCC)

7 DISConnected to a capacitor whose discharge time will influence the

timing interval

8V+,

VCCThe positive supply voltage which must be between 3 and 15 V

Monostable mode

The relationships of the trigger signal, the voltage on C and the pulse width in

monostable mode

In the monostable mode, the 555 timer acts as a one-shot pulse generator. The pulse

begins when the 555 timer receives a trigger signal. The width of the pulse is

determined by the time constant of an RC network, which consists of a capacitor (C)

and a resistor (R). The pulse ends when the charge on the C equals 2/3 of the supply

voltage. The pulse width can be lengthened or shortened to the need of the specific

application by adjusting the values of R and C.[6]

The pulse width of time t, which is the time it takes to charge C to 2/3 of the supply

voltage, is given by where t is in seconds, R is in ohms and C is in farads. See RC

circuit for an explanation of this effect.
http://en.wikipedia.org/wiki/Capacitorhttp://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/555_timer#cite_note-5#cite_note-5http://en.wikipedia.org/wiki/555_timer#cite_note-5#cite_note-5http://en.wikipedia.org/wiki/555_timer#cite_note-5#cite_note-5http://en.wikipedia.org/wiki/Ohmshttp://en.wikipedia.org/wiki/Faradshttp://en.wikipedia.org/wiki/RC_circuithttp://en.wikipedia.org/wiki/RC_circuithttp://en.wikipedia.org/wiki/RC_circuithttp://en.wikipedia.org/wiki/RC_circuithttp://en.wikipedia.org/wiki/RC_circuithttp://en.wikipedia.org/wiki/Faradshttp://en.wikipedia.org/wiki/Ohmshttp://en.wikipedia.org/wiki/555_timer#cite_note-5#cite_note-5http://en.wikipedia.org/wiki/Resistorhttp://en.wikipedia.org/wiki/Capacitor


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555 TIMER

Astable mode

In astable mode, the '555 timer ' puts out a continuous stream of rectangular pulses

having a specified frequency. Resistor R1 is connected between VCC and the discharge

pin (pin 7) and another resistor (R2) is connected between the discharge pin (pin 7),

and the trigger (pin 2) and threshold (pin 6) pins that share a common node. Hence the

capacitor is charged through R1 and R2, and discharged only through R2, since pin 7

has low impedance to ground during output low intervals of the cycle, therefore

discharging the capacitor.


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Specifications

These specifications apply to the NE555. Other 555 timers can have better

specifications depending on the grade (military, medical, etc).

Supply voltage (VCC) 4.5 to 15 V

Supply current (VCC = +5 V) 3 to 6 mA

Supply current (VCC = +15 V) 10 to 15 mA

Output current (maximum) 200 mA

Power dissipation 600 mW

Operating temperature 0 to 70 C
http://en.wikipedia.org/wiki/Operating_temperaturehttp://en.wikipedia.org/wiki/Operating_temperature


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PRINCIPLE OF WORKING

The basic problem with most of standard light sensors is that they require precise

alignment of light beam to mute the circuit during standby mode. The circuit

described here is so sensitive that it will detect a moving person at a distance of few

metres in daylight or under electric lighting without cumbersome

alignment of light beam. It requires virtually no set up, and may be simply placed

within the line-of-sight of almost any light source including ambient day light or

fluorescent electric light. The beep generated from the circuit will be loud enough to

detect the entry of a person in the room or the protected area being guarded. The

circuit uses a voltage comparator and a monostable timer to give the warning alarm on

detecting a moving person. IC A741 (IC1) is used as a voltage comparator with two

potential

dividers in its inverting and noninverting inputs. Resistors R1 and R2 provide half-

supply voltage of 4.5 volts to its inverting input (pin 2). LDR1 and preset VR1 form

another potential divider to provide a variable voltage input to the non-inverting input

(pin 3). If VR1 is properly adjusted for the required light level, the output of IC1 will

be high, which drives pnp transistor T1 out of conduction. This is due to the high

potential at the base of T1. The emitter voltage of T1 will be high in this condition,

which inhibits IC2 from oscillation and LED1 from lighting. IC2 is wired as a

monostable timer. R6 and C2 provide a preset time delay.

As a person crosses the protected area, his shadow will be sensed by LDR1 due to

change in the light intensity level and the voltage at the non-inverting input of IC1

will drop momentarily. The output of IC1 suddenly becomes low, allowing T1 to

conduct. This triggers the monostable (IC2) and the alarm sounds. Assemble the

circuit on a common PCB and house in a plastic case. Keep LDR1 inside a black tubeto increase its sensitivity. Adjust preset VR1 until LED1 turns off at the particular

light level. Keep LDR1 facing the entrance of the room or the area to be protected.

Sensitivity of the circuit depends on the proper adjustment of VR1. If VR1 is

correctly adjusted, the circuit can detect a moving person from a distance of about

three metres.


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DESIGN & MAKING PCB

A PCB is a rigid flat board, which holds electronics component. This board is made

up of layers that interconnect component via a pathway. Let us know how to prepare a

PCB.

Step I Firstly arrange all of the component of the project & testing them for a

Proper working.

Step II Perform pre testing of circuit on bread board, if the circuit working

properly then start to make PCB.

Step III Draw the layout of circuit on inch graph paper with proper dimension

.Ensure that if layout correct then draw it on trace paper. The layout can be

traced on the board by screen printing.

Step IV Cut the CCB (Copper Clad Board) of the same size of layout.

Step V Put the carbon paper on the PCB and trace from the reverse side of the

layout. Outline the impression of layout on PCB and apply permanent

marker.

Step VI Etching: Etching is the process in which excess layer of copper is

removed to leave the individual tracks as they are. The PCB plate is

immersed in solution of FeCl3 + some drops of HCL or H2So4. Shake it

well till the copper is totally removed excepting the printed layout path.

Step VII After taking off the solution rinse the PCB plate with clean water and dry

it. Then removed the print layer with the help of thinner and a piece of

cloth. Check the continuity of tracks with the help of multimeter.

Step VIII Drill the end points of the component on the lay out with the help of drill

machine. Clean the legs of the component with the help of sand paper tip it

with the help of soldering iron. Place the component as per circuit on PCB

in the proper way.

Step IX Apply Flux on legs of the component & solder them. Cut the remaining

legs of the components. Now the PCB is ready to connect the external

power supply and the external output or input devices.


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APPLICATIONS

1. Photodiodes are often used for accurate measurement of light intensity in

science and industry. They generally have a better, more linear response than

photoconductor.

2. The shadow alarm circuit can sense one or more moving shadow in a confined

area.

3. It can be used to protect things from theft.

4. This opto-sensitive circuit sounds an alarm whenever anyone crosses the

fence. So it can be used at night by shopkeepers to protect the valuables in

their showrooms.

5. LDR does not require an aligned light beam to illuminate the photo-sensor

6. It has low cost comparing other security systems.

LIMITATIONS

1. A dim lighting in the room is necessary to detect the moving shadow.

2. It is necessary that shadow falls properly on LDR.

3. Shadow alarm is an electronic device so we have to prevent it by moisture.

4. If alarm is not properly audible then device can not be used as a security

purpose.

CONCLUSION

The shadow alarm work as a watchman in our houses to protect our valuable things.

The shadow alarm circuit can sense a moving shadow in a confined area. It can be

used to protect things from theft. When somebody approaches the unit, it will give a

loud alarm to abort the attempt of theft.


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REFERENCE

1. Idea about shadow alarm fromwww.electronics4u.com

2. www.electroschematics.com

3. http://www.ic-on-line.cn/IOL/datasheet/l14f1_201714.pdf

4. Information about Photodiode from R.S.Sedha & A.K. Sawhny.

5. Information about Opamp from Gayakwad.

6. www.wikipedia.com

7. And other electronic Books.
http://www.electronics4u.com/http://www.electronics4u.com/http://www.electronics4u.com/http://www.electroschematics.com/http://www.electroschematics.com/http://www.ic-on-line.cn/IOL/datasheet/l14f1_201714.pdfhttp://www.ic-on-line.cn/IOL/datasheet/l14f1_201714.pdfhttp://www.wikipedia.com/http://www.wikipedia.com/http://www.wikipedia.com/http://www.ic-on-line.cn/IOL/datasheet/l14f1_201714.pdfhttp://www.electroschematics.com/http://www.electronics4u.com/


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APPENDIX

1. DATASHEET OF PHOTO-TRANSISTOR L14F1

The L14F1 are silicon photodarlingtons mounted in a narrow angle, TO-18 package.

Some of their Features include-

Hermetically sealed package

Narrow reception angleIt is the most sensitive photo-sensor to detect shadows. It is portable and can be usedat any place that is to be monitored.

Dimensions

1. Dimensions for all drawings are in inches (mm).2. Tolerance of .010 (.25) on all non-nominal dimensionsunless otherwise specified.

SPECTRAL RESPONCE


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2. DATASHEET OF 741 Opamp

The A741 is a general-purpose operational amplifier featuring offset-voltagenull capability. The high common-mode input voltage range and the absenceof latch-up make the amplifier ideal for voltage-follower applications. The

device is short-circuit protected and the internal frequency compensationensures stability without external components. A low value potentiometer maybe connected between the offset null inputs to null out the offset voltage as

shown in Figure 2. The A741C is characterized for operation from 0C to

70C. The A741I is characterized for operation from 40C to 85C.The

A741M is characterized for operation over the full military temperature range

of 55C to 125C.


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3. DATASHEET OF 555 TIMER

The 555 monolithic timing circuit is a highly stable controller capable of producing

accurate time delays, or oscillation. In the time delay mode of operation, the time is

precisely controlled by one external resistor and capacitor. For a stable operation as anoscillator, the free running frequency and the duty cycle are both accurately controlled

with two external resistors and one capacitor. The circuit may be triggered and reset

on falling waveforms, and the output structure can source or sink up to 200mA.


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LIGHT FENCE

Minor Project File

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Transcript of Minor Project File