Home Security

Home Security

SYNOPSIS Taking in consideration the need of security, it has become very essential to design security systems which should be reliable effective and economical. The home security system is act for same purpose to guide and economical and a convenient security. This project involves a laser torch which is easily available and it is used for operation of these device. The project has a combination of plane mirrors which are arranged around the house to form a net. The laser beam is directed on mirrors firstly. After proper reflection on mirrors it finally fall on LDR. The laser beam should be continuously aimed on LDR. Any interruption of the laser beam will result into energization of the alarm and give the signal of security disturbance. This is the ideal and short working of the house security system. This simple arrangement indicates in a security disturbance in the laser net.

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Home Security

INTRODUCTION In designing some precious things security is of prime importance. Security is becoming essential day-to-day due to increasing theft. Security should not be expensive then the think to be secured. This project guides us with a low cost security. To protect our house or any precious things from thieves or trespassers for designing any thing new security should be viewed first. This project gives us a security system, which insures safety and security very conveniently. It is simple as it wcrks on a simple laser beam and a proper mirror arrangement around the thing to be secured. By networking the laser beams through reflections of mirror and by blowing the alarm if any one crosses the beam and indicating “security in danger”. The system convenience comfort of the user it uses the most advance technology. Innovation quality assurance and reliability are silent features of system.

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Home Security

METHODS OF HOME SECURITY The past method of security included of Burglar Alarm The details of these system are as follows BURGLAR ALARM In this system invisible radiation like ultra violet rays or infrared rays fall continuously on photodetector. When burglar crosses the path of beam, the current in photodetector is cut off. The relay in the circuit is set in such manner as to be operated due to this break in current and it starts the ringing of an alarm bell. 1) Burglar Alarm using Photo conducting cell :Here is simple circuit, which uses photoconductive cell LDR (light dependant resistor). The LDR is made up of cadmium selenide or cadmium sulphide.

Its resistance is very high when it is dark and its resistance falls

considerably when it is illuminated. This light dependent properly of LDR is used in construction of Burglar alarm system. When LDR is illuminated by light from the resistance of LDR drops to few ohms and transistor emmiter base junction in forward biased. This make the transistor to go in saturation and sufficient current flow through the relay coil this current is sufficient to actuate the relay. The between in relay ckt will not work .

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Home Security +Vcc Bulb LDR

AC

Relay R2

R1

Bell

Circuit Diagram of a Burglar Alarm

AC Supply

But when light from bulb is interrupted by burglar the LDR resistance become very high. The base emitter voltage is very small. This small voltage is insufficient to forward bias the base emitter junction of transistor. The transistor is in cut off state. The current through relay coil is not sufficient and relay current operate the bell and hence an indication of alarm. Stating that there is some one to interrupt the light. 2. Burglar Alarm Using Photo emissive Cell. We shall consider here the automatic burglar alarm. The photo electric or photo emmisive cell forms part of grid circuit of triode, in plate circuit of which there is relay which works burglar alarm. As long as light in incident on Govt.Poly.Washim

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Home Security cell the electrons keep the grid of triode more negative and hence, the relay is not operated. Hence bell B does not ring. But as soon as some intruder or burglar breaks into house and on entering comes in way of invisible beam, the grid becomes less negative. The plate current increases and sets the relay. The bell starts ringing and will continue ringing till the relay is reset. Burglar alarm can be also be built with the help of LDR in conjunction with 555 timer. Disadvantage of security :1) This security system is Costly. 2) This security system cannot cover a large area under security. 3) Circuit Design is typical. 4) Security system is applicable for limited purpose only. 5) Numbers of Batteries Required to run the system is more.

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Home Security

SYSTEM COMPONENTS 1) I.C.555 2) LDR 3) N.P.N. TRANSISTOR 4) CAPACITOR 5) LASER TORCH 6) RESISTANCE 7) ADAPTER 8) SPEAKER 9) MIRRORS 10) FLEXIBLE WIRES

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Home Security

DECRIPTION OF COMPONENTS 1]

IC 555 :IC 555 is a timer IC. It is important in consumer and industrial

applications. The internal block diagram of IC 555 as shown below. VR Sk

R Q2

Reset (4)

Threshold (6) 2/3Vcc C1

Control Voltage (5) 5K

R

Buffer FLIP FLOP

R

Q Out put (3)

1/3Vcc

+ _ C2

S

trigger (2) 5k

R 100 Ω

Discharge (7) Q1 (1)

GND

The internal block diagram consist of 6 main parts. 1) Resistor divider network.

4) Reset circuitry

2) Comparator C1 and C2

5) Discharge circuitry

3) Flip – flop ( Rs – FF )

6) Output buffer

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Home Security The block diagram consist of two comparators that drives the set (S) and reset ® terminal of a flip flop which is in turns controls the ON and OFF CYCLE of the discharge transistor Q1. The comparator reference voltages are fixed at 2/3 Vcc for C1 and 1/3 Vcc for C2 by means of voltage divider made of 3 resistors. The reference voltage is applied to control the timing.  The timing can be externally controlled by applying voltage to terminal 5.  If no such control is required then it is bypassed by a capacitor to ground.  The capacitor value is about 0.01 uf.  On the negative transition of the pulse applied to the trigger terminal and when the voltage of the trigger terminal pass through Vcc/3  The O/p of C2 comparator changes. This changes the state of the flip-flop

and the O/p of flip-flop is low.  On the other hand, when the voltage applied at the threshold terminal of the

comparator C1 goes positive and passes through the reference 2/3 Vcc, the output of C1 changes and this in turn changes the state of flip-flop and O/p goes high.  A separate reset terminal is provided for the timer, which reset the flip-flop externally.

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Home Security  This reset voltage applied externally over ride the effect of the O/p of lower comparator, which sets the FF.  The over rinding effect when terminal is less than 10.4 V.  When reset terminal is not in use, connected to Vcc.  Transistor Q2 acts as a buffer, isolating the reset terminal from the flip-flop

and transistor Q1.  The output of flip-flop is Q1; which is the O/p stage.

 When the flip-flop is reset, the output stage is low and when set, the output is high.  A capacitor is connected between discharge and ground.  When Q1 is off, the capacitor charges and when Q1 is on, capacitor

discharges through it.

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Home Security

PIN DIAGRAM OF IC 555 IC 555 is a 8 pin timer I.C. The pin diag. is as shown below. GND

+Vcc

Trigger

IC

Discharge

O/p

555

Threshold

Reset

Control volt

The function of various pins is as following Pin 1 Ground :- All voltages are measured with respect to this terminal. Pin 2. Trigger :- The O/p of timer depends on amplitude of external trigger pulse applied to pin Pin 3. O/p :- There are two ways load can be connected to O/p terminal either between pin 3 and ground (pins) or between pins3 and supply voltage and Vcc (pins) Pin 4 Reset : The device 555 is reset ( disabled by applying is negative pulse to this pin when the reset function is not in use, the reset terminal should be connected to +Vcc to avoid any possibility of flash trigerring. Pin 5 :- Control voltage :- An external voltage applied to this terminal changes the threshold as well as trigger voltage. In other words, by imposing a voltage on Govt.Poly.Washim

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Home Security this pin or by connecting a potentiometer between this pin and ground, the pulse width the output waveform can be varied. When not used, the control pin should be bypassed to ground with a 0.01 uf capacitor to prevent any noise disturbances. Pin 6 : Threshold :- This is the non-inverting terminal of capacitor C1 which monitors the voltage across the external capacitor. When the voltage at this pin is greater than or equal to 2/3 vcc, the O/p of comparator C 1 goes high, which in turn switches. The output of the timer low. Pin 7 : Discharge : The pin is connected internally to the collector of transistor Q1. When the O/p is high, Q1 is Off and acts as an open circuit to the external capacitor connected between pin 7 and ground. On the other hand, when the O/p is low, Q1 is saturated and acts as a short circuit, shorting out the external capacitor 0 to ground. Pin 8 : Vcc :- The supply voltage of +5v to 18v is applied to this pin with respect to ground (pin 1)

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Home Security

Application of IC 555 1) A stable, Monostable, Bistable Multivibrator. 2) DC – to DC converter ( Chopper circuit ) 3) Wave form generator. 4) Techometer – ( for speed measurement ) 5) Temperature measurement. 6) Analog frequency meter. 7) Voltage regulator. 8) Voltage Control Oscillator (VCO) 9) Schmitt trigger ( sine to square wave generator ) 10) Ramp Wave generator. 2] LDR :LDR is a semiconductor resistor whose resistance decreases ( conductance increases) when irradiated it is also known as photo resistors, or photo sensitive device and LDR has high resistance under dark condition and low resistance when irrediated by light. Application of LDR :1) Used as photo electric counter like meters, ON-OFF switch etc. Specification :1) Dark resistance > 10 mr,

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Home Security 2) Resistance under light of intensity 1000LUX : 100 to 300 r , 3) Permissible voltage 100V peak. 4) Capacitance < 10 pF. 3] TRANSISTOR Transistor is developed in ‘P’ and ‘N’ type semiconducting materials from the same crystal by adding corresponding impurities. Transistor consist of two P – N Junction formed by sandwitch pattern of either P type or N – type material between a pair of opposite type semiconductor materials. It means if two outermost layers are of P-type material present then in between this two, N-type material is sandwitched and if two outermost layer are of N-type material then in between these two P-type material is sandwitched. According to this theory of sandwitching the layer there are two basic types of transistors. (i) N – P – N type transistor (ii) P – N – P type transistor. We have used the ‘’N – P – N type transistor’’ details are as follows N

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P

N

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Home Security

The symbolic representation of N.P.N. E

B

C Block diagram of N – P – N type trans. n

I1

P

I2

n

IE

IC

IC

VEB

VCB

V E B – The bias applied is between base – Emmiter V C B – The bias applied is between base collector. IE

- Emitter current

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Home Security Ic

- Collector C/N

IB

- Base C/N

Circuit details :The forward bias VEB is applied to Base – Emitter Junction of the transistor and reverse bias VCB is applied to Base – Collector – Junction. Operation :Transistor consist of 3 layer of semi conducting material i.e. N – P – N forward bias (VBE) is applied in between the emitter and base of the transistor. The electrons of N – type region are energized and starts to move towards the opposite charged particles, ( i.e. holes ) present in middle. P – type region forward bias is given to N – type material, more and more no. of electrons are injected from emitter and starts to flow towards the base is lightly doped hence it is having minimum no. of holes. The electrons cross over Junction J1 then start to combine with the hole present in P-region the no. of holes are comparatively low hence minimum no. of electrons combine with this holes and rest of electrons cross over the Junction J2 and collected at the terminal collector ( i.e. next N – type section ) reversed bias VBC is applied to N – type region it exert attraction power of electron and so more no. of electrons come in collector region. The movement of electrons in emitter constituted the emitter. Cu.(IE) combination of holes and electrons take place at base this electron go

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Home Security through the holes towards base terminal they constituted small value of base C/N IB, rest of maximum no of electrons comes to collector C/N Ic) this Ic then flows through the external circuit towards emitter the base C/N IB flowes through external circuit. The direction of flow of Ic and IB are same ( flow of Ic and IB are same ( i.e. towards terminal emitter ) so the resultant emitter C/N is the combination of collector C/N ‘IB’ Hence, IE = IB + IC The unit of resistance is ohm the resistance can be also express as R = ρ  /A Where ρ - specific resistances in Ω m 

- length in m

A

- cross sectional Area in m2

Classification of resistor :Resistor are made in many shapes and size, wire wound resistor have different values depending upon this specific resistively of the wires. The cross sectional area and length of the wire i.e. use for making heat. Because C/N carrying capability of wires the size of resistor changes depending upon the wattage

Resisters Fixed 1) Wire wound 2) Carbon 3) Film

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Adjustable 1) Wire wound 2) Trapped wire wound

Potentiometer 1) Wire wound 2) Carbon

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Home Security 4] CAPACITOR Capacitor can be define as a property of electrical circuit that can apposes the change in voltage.

Capacitor storage the energy in the form of

electricity and releases it. When used in the circuit current. Any two metal conductor when separated from each other by a dielectric constitute.

Capacitance an electric field is developed between two

charged plates within the space between plates energy stored in the capacitor is in this electric field. The unit of capacitance is farad named after the Michael farads. C = q /V = Where

Coloumb Voltage

q = charge v = voltage or

c=

ε E0A d

A = Area in cm2

Where

ε = Dielectric constant. d = Distance in cm. Dielectric constant in medium while permits the establishment of lines of forces between oppositely charged plates.

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Home Security There are two types of capacitor used 1] POLISTER 2] ELECTROLYTIC 5] LASER TORCHE :Laser torch is used for radiations of laser beam which is imposed on mirrors arrange systematically whose reflection surrounds the house and then reflected towards LDR. The laser torch used for these security purpose is 3v.

6] RESISTANCE :Different resistance of + 4.7 Kr, 220 r, 1 Kr, 47 Kr and 3.3 kr are used in circuit as per the requirement in opposition to flow of current. They are mounted properly 1 PCB, wherever necessary. The direct C/N resistance has a controlling effect in amount of C/N that flows when a certain voltage is applied according to ohmslow I = V/R 7] ADAPTER :As direct supply from switch board cannot be given to circuit, adapter is used to step down supply voltage and bring it to desired volt i.e. 12 V essential for circuit to run. Adapter is close circuit which consist of step down transformer, rectifier etc.

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Home Security 8] SPEAKER :Speaker is used for siren purpose. which provides a noise whenever security is danger. Speaker is a device which converts varying electrical signal into a proportional sound signal. 9] MIRRORS :For reflecting laser beam combination of plain mirrors M1 through M4 is used to direct the laser beam around the house to form a net. 10] FLEXIBLE WIRES :Flexible wires are most important as a complete circuit. On a PCB can only be obtained from wires. Flexible wires are used for connection purpose. The most important purpose is conduction. Flexible wires may have single or multi-strength of metal. They are used as per current capacity. These are insulated wires and has a low current carrying capacity and soldering metal is used to solder electronic components on PCB with the help of soldering.

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Home Security

WORKING OPERATION OF SYSTEM Receiver Unit and its working Description :- In receiver unit we have used IC 555 in A stable multi vibrator there is continuous ON/OFF of pulses. PIN No.4 of IC 555 is RESET. ON this pin we have given O/P of transistor 547. The transistor acts as a switch to RESET. The LDR voltage is given to base of transistor. According to which Speaker

the RESET period is varied.

LDR CIRCUIT DESIGN OF RECEIVER UNIT Govt.Poly.Washim

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Home Security Working :When LASER beam falls on LDR through mirrors, the resistance of LDR is negligible. This makes ‘OFF STATE’. Thus the O/p of IC 555 gives Low or zero voltage and speaker remains open. As any thief crosses the LASER beam is interrupted. The resistance of LDR become large. This gives base pulse to transistor. Thus IC 555 gets RESET pulse. The O/P goes HIGH or maximum. The speaker gets close and sound is produced. It is reseted by switch. Working Working of IC 555 when used on Astablemode Astable Multivibrator The Figure shows the astable mode of IC 555 with the wave forms. In this mode, capacitor charges towards Vcc through RA & RB Untill Vc = 1/3 Vcc At this point comparator C1 changes the state and capacitor starts discharging through RB This continues until the Vc = 1/3 Vcc At this stage comparator C2 changes the state and the capacitor again starts charging and so on.

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1K

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LDR

4.7K

CIRCUIT DESIGN WITH RESPECTIVE VALUES

NPN 547 0.01µF

17K

1K

0.01µF

100µF

Home Security

Speaker

3.3 K

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Home Security Consider that the capacitor is periodically discharged and charged between 2/3 Vcc and Vcc/3. During the Charging time 0 ≤ t ≤ Tc, the voltage across capacitor Vc equals,

[

C

]

Vc = 2 / 3Vcc l − e −1/( RA + R1 + ) + Vcc / 3 ………………..

(1)

at t = Tc,, Vc =2/3 Vcc

[

∴ 2/3 Vcc = 2/3 Vcc l − e −1 /( R c

A + RB )

C

] + Vcc / 3

∴ Tc = (RA + RB)C./n(2) ∴ Tc = 0.693 (RA+RB).C

……………. (2)

During the discharging time 0 ≤ t ≤ TD, We have Vc=2/3 Vcc.e-t/RBC

…………… (3)

At t = TD, Vc = 1/3 Vcc ∴ 1/3 Vcc = 2/3 Vcc e-TD/RBC ∴ TD = RBC/n(2) ∴ TD = 0.693 RBC Total Time. T=TC + TD

…………

T = 0.693 (RA + 2 RB) C…………. Duty Cycle. D =

TC × 100 T

D=

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(5)

…………..

RA + RB × 100 ……. RA + 2 RB

(4)

(6)

…… (7)

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Home Security Steps :1) Assume value of capacitor C for Astable Multivibrator lies between 500 pF < C < 100µF 2) Calculation of RB :RB =

1.4(1 − d ) f o .C

RB must lie between 1 KΩ < RB < 3.5 MΩ Where, d = duty cycle fo = frequency of astable m.v. 3) Calculation of RA : RA =

RB (2d − 1) RA must lie between 1 KΩ < RA < 3.3 MΩ. (1 − d )

4) To prevent noise disturbances, bypass capacitor C1 is connected between pin 5 and ground (Pin 1). C1= 0.01 µF 5) To eliminate unwanted voltage spike in the output waveform a bypass capacitor C2 of the value 10µF is connected between (Pin 8 and Pin 1). C2 = 10µF 6) Charging Period. Tc = 0.693 (RA + RB).C sec

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Home Security

7) Discharging Period. TD = 0.693 (RB.C) sec 8) Total time period. T=0.693 (RA + 2RB).C sec 9) Duty Cycle. %D =

( RA + RB ) × 100 sec RA + 2 RB

10) Frequency fo =

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1.44 H ( RA + 2 RB ) C Z

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Home Security

TESTING Testing of fault For any fault found in the circuit following procedure should be adopted. 1) Check LDR if its Faulty replace it. 2) Check all resisters and capacitors using multimeters. 3) Check IC on IC tester. 4) Loose connections due to dry soldering should be corrected. Testing working of MODEL You Testing the security system first Laser torch is “ON” and a Laser net work in formed using mirrors as discussed before. After this an obstracle is brought in network to test performance and certainly it is observed that horn blows this signal guides us with reliability of model and indicates about the danger and abouts us regarding security. This also guide us with that how security can be obtain conveniently and chiefly.

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Home Security

Speaker Power supply

Laser torch

LDR

Receiver uint

Laser net

MODEL SKETCH OF SYSTEM

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Home Security

ADVANTAGES AND DISADVANTAGES Advantages :1) It is cheap and economicl 2) This security system is very reliable. 3) The operation is very easy 4) It has simple in design. 5) Large area can be secure by this system very easily. 6) This system is also applicable for many purpose such as guarage, bank, society, industries. 7) It has quick response 8) Maintenance cost is very low. 9) It can use at any condition or atmosphere. 10) Easy to control. 11) It is more reliable and effective than manual security. 12) It ‘require’ less space for erection (installation) 13) It has good future scope.

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Home Security

Disadvantages :1) In this security system there is disadvantage of a visible laser ray’s which can alert the theif . 2) Laser ray’s are harmful for Retina i.e. Eyelsight 3) Disturbance in mirror can also blow the horn

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Home Security

FUTURE EXPANSION The receiver unit comprises two identical step down transformers (X1 and X2), two 6V relays (RL1 and RL.2). an LDR. A transistor, and a few other passive components. When switches S1 and S2 are activated, transformer X1, followed by a full-wave rectifier and smoothing capacitor C1, drives relay RL1 through the laser switch. The laser beam should be aimed continuously on LDR. As long as the laser beam falls on LDR, transistor T1 remains forward biased and relay RL1 is thus in energized condition. When a person crosses the line of laser beam, relay RL1 turns off and transformer XZ gets energized to provide a parallel path across N/C contact and the pole of relay RL1. In this condition, the laser beam will have no effect on LDR and the alarm will continue to operate as long as switch S2 is on. When the torch is switched on, the pointed laser beam is reflected from a definite point/place on the periphery of the house. Making use of a set of properly oriented mirrors one can form an invisible net of laser rays as shown in the block diagram. The final ray should fall on LDR of the circuit.

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Home Security

CIRCUIT DESIGN FOR INFRA RED RAYS SECURITY SYSTEM

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Home Security

REFERENCE 1) Linear integrated circuit. Ramakant Gaikwad 2) Electronics and component Madhuri A. Joshi 3) Linear integrated circuit Prof. N.P. Mawale 4) Electronics for you July 2001 5) OP-Amp Ravindra Chaudhari

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