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NATIONAL INSTITUTE OF TECHNOLOGY

SRINAGAR

A

Seminar Report

On

“EMBEDDED BASED HOME SECURITY SYSTEM”

By

Jitendra Kumar

416/11

dhaka.jiten@gmail.com

DEPARTMENT OF

ELECTRONICS &COMMUNICATION ENGINEERING

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CONTENTS

Introduction

General Architecture

Various Components

Working

Applications

Advantages

Future Scope

Conclusion

References

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INTRODUCTION

When we talk about the security the one thing come in mind that whether our home is

secure or not. Our home has always important documents, money and other precious things,

that need to be protected from the intruders or thieves.

In today’s age of digital technology and intelligent systems, home automation has

become one of the fastest developing application-based technologies in the world. The idea of

comfortable living in home has since changed for the past decade as digital, vision and

wireless technologies are integrated into it. Intelligent homes, in simple terms, can be

described as homes that are fully automated in terms of carrying out a predetermined task,

providing feedback to the users, and responding accordingly to situations. In other words, it

simply allows many aspects of the home system such as temperature and lighting control,

network and communications, entertainment system, emergency response and security

monitoring systems to be automated and controlled, both near and at a distance. Automated

security systems play an important role of providing an extra layer of security through user

authentication to prevent break-ins at entry points and also to track illegal intrusions or

unsolicited activities within the vicinity of the home (indoor sand outdoors).

There has been much research done in the design of various types of automated security

systems. Many security systems are based on only a single system. In an event of system

failure or intrusion of the user authentication, there is no backup system to monitor the home

continually. Thus, a feasible system should be effective, practical and reasonable in cost. In

this report, we proposed an integrated based home security system, consisting an IR sensor

and GSM Module.

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GENERAL ARCHITECTURE

The proposed general architecture incorporates subsystems IR sensors, GSM module

into a single automated architecture for practical implementation in intelligent home

environments. The figure shows a simple architecture diagram of the proposed system and

its setup and connectivity. The modules work independently and parallel but share

computational resources.

Figure-1 Simple Architecture of GSM home security system

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Overview of Components Used in Architecture

AT89S52 Microcontroller

LCD Display

IR Sensor

GSM Module

LED

MAX232 IC

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AT89S52 Microcontroller

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K

bytes of in-system programmable Flash memory. The device is manufactured using Atmel’s

high density non-volatile memory technology and is compatible with the industry standard

80C51 instruction set and pinout. The on-chip Flash allows the program memory to be

reprogrammed in-system or by a conventional non-volatile memory programmer. The Atmel

AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-effective

solution to many embedded control applications. The AT89S52 provides the following

standard features:

Features

8K bytes of Flash,

256 bytes of RAM,

32 I/O lines, Watchdog timer,

2 data pointers,

Three 16-bit timer/counters,

A six-vector two-level interrupt architecture,

A full duplex serial port,

On-chip oscillator,

4.0V to 5.5V Operating Range

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Pin Diagram

The 8051 microcontroller consists of 40 pins. These pins are well represented by the pin

diagram below.

Figure- 2 Pin Diagram of 8052 Microcontroller

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Pin Description

Pin No Function Name

1 External count input to Timer/Counter 2, clock-out T2 P1.0

2 Timer/Counter 2 capture/reload trigger and direction

control T2 EX P1.1

3

8 bit input/output port (P1) pins

P1.2

4 P1.3

5 P1.4

6 P1.5

7 P1.6

8 P1.7

9 Reset pin; Active high Reset

10 Input (receiver) for serial

communication RxD

8 bit input/output port (P3) pins

P3.0

11 Output (transmitter) for serial

communication TxD P3.1

12 External interrupt 1 Int0 P3.2

13 External interrupt 2 Int1 P3.3

14 Timer1 external input T0 P3.4

15 Timer2 external input T1 P3.5

16 Write to external data memory Write P3.6

17 Read from external data memory Read P3.7

18 Quartz crystal oscillator (up to 24 MHz)

Crystal 2

19 Crystal 1

20 Ground (0V) Ground

21

8 bit input/output port (P2) pins

/ High-order address bits when interfacing with external memory

P2.0/ A8

22 P2.1/ A9

23 P2.2/ A10

24 P2.3/ A11

25 P2.4/ A12

26 P2.5/ A13

27 P2.6/ A14

28 P2.7/ A15

29 Program store enable; Read from external program memory PSEN

30 Address Latch Enable ALE

Program pulse input during Flash programming Prog

31 External Access Enable; Vcc for internal program executions EA

Programming enable voltage; 12V (during Flash programming) Vpp

32

8 bit input/output port (P0) pins

Low-order address bits when interfacing with external memory

P0.7/ AD7

33 P0.6/ AD6

34 P0.5/ AD5

35 P0.4/ AD4

36 P0.3/ AD3

37 P0.2/ AD2

38 P0.1/ AD1

39 P0.0/ AD0

40 Supply voltage; 5V (up to 6.6V) Vcc

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Internal Block Diagram of 8051 Microcontroller

Figure-3 Internal block diagram of 8051 Microcontroller

Memory Architecture

The 8051 has two types of memory and these are Program Memory and Data Memory. All

8051 microcontrollers have a 16-bit addressing bus and are capable of addressing 64 kb

memory.

Program Memory: - Program Memory (ROM) is used to permanently save the program

being executed

Data Memory: - Data Memory is used for temporarily storing data and intermediate results

created and used during the operation of the microcontroller

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Figure-4 Memory Banks in 8051 Microcontroller

Special Function Registers (SFRs)

Special Function Registers (SFRs) are a sort of control table used for running and monitoring

the operation of the microcontroller.

A Register (Accumulator)

A register is a general-purpose register used for storing intermediate results obtained during

operation. Data to be moved from one register to another must go through the

accumulator. In other words, the A register is the most commonly used register and it is

impossible to imagine a microcontroller without it.

B Register

Multiplication and division can be performed only upon numbers stored in the A and B

registers. All other instructions in the program can use this register as a spare accumulator.

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Liquid Crystal Display (LCD)

A liquid crystal display (LCD) is a thin, flat electronic visual display that uses the light

modulating properties of liquid crystals (LCs). They are used in a wide range of applications,

including computer monitors, television, instrument panels, aircraft cockpit displays etc.

They are common in consumer devices such as video players, gaming devices, clocks,

watches, calculators, and telephones. LCDs have displaced cathode ray tube (CRT) displays

in most applications. They are usually more compact, lightweight, portable, less expensive,

more reliable, and easier on the eyes. They are available in a wider range of screen sizes

than CRT. LCDs are more energy efficient and offer safer disposal than CRTs. Its low

electrical power consumption enables it to be used in battery powered electronic

equipment.

Figure-5 LCD

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Infra-Red Sensor (IR Sensor)

The basic principle of IR sensor is based on an IR emitter and an IR receiver. IR emitter

will emit infrared continuously when power is supplied to it. On the other hand, the IR

receiver will be connected and perform the task of a voltage divider. IR receiver can be

imagined as a transistor with its base current determined by the intensity of IR light

received. The lower the intensity of IR light cause higher resistance between collector-

emitter terminals of transistor, and limiting current from collector to emitter. This change of

resistance will further change the voltage at the output of voltage divider. In others word,

the greater the intensity of IR light hitting IR receiver, the lower the resistance of IR receiver

and hence the output voltage of voltage divider will decreased. The further distance away

between emitter and receiver decrease the amount of infrared light hitting the receiver if

the distance between the sensor and a reflective surface is fixed.

Figure- 6 infrared sensor

Infrared radiation is the portion of electromagnetic spectrum having wavelengths longer

than visible light wavelengths, but smaller than microwaves, i.e., the region roughly from

0.75μm to 1000 μm is the infrared region. Infrared waves are invisible to human eyes. The

wavelength region of 0.75μm to 3 μm is called near infrared, the region from 3 μm to 6 μm

is called mid infrared and the region higher than 6 μm is called far infrared. (The

demarcations are not rigid; regions are defined differently by many).

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Voltage Regulator

A Voltage Regulator is an electrical regulator designed to automatically maintain a

constant voltage level. Depending on the design, it may be used to regulate one or more AC

or DC voltages. A basic voltage regulator LM7805 has three legs, converts varying input

voltage and produces a constant regulated output voltage.

Figure-7 Voltage Regulator

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Light Emitting Diodes (LED’s)

LEDs present many advantages over incandescent light sources including lower energy

consumption, longer lifetime, improved robustness, smaller size, faster switching, and

greater durability and reliability. LEDs powerful enough for room lighting are relatively

expensive and require more precise current and heat management than compact

fluorescent lamp sources of comparable output.

.

Figure-8 Light-Emitting Diodes (LED‟s)

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GSM Module

GSM (Global System for Mobile) / GPRS (General Packet Radio Service) TTL –Modem is

SIM900 Quad-band GSM / GPRS device, works on frequencies 850 MHZ, 900 MHZ, 1800

MHZ and 1900 MHZ. It is very compact in size and easy to use as plug in GSM Modem. The

Modem is designed with 3V3 and 5V DC. TTL interfacing circuitry, which allows User to

directly interface with 5V Microcontrollers (PIC, AVR, Arduino, 8051, etc.) as well as 3V3

Microcontrollers (ARM, ARM Cortex XX, etc.). The baud rate can be configurable from 9600-

115200 bps through AT (Attention) commands. This GSM/GPRS TTL Modem has internal

TCP/IP stack to enable User to connect with internet through GPRS feature. It is suitable for

SMS as well as DATA transfer application in mobile phone to mobile phone interface. The

modem can be interfaced with a Microcontroller using USART (Universal Synchronous

Asynchronous Receiver and Transmitter) feature (serial communication).

Figure-9 GSM Module

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Features

Quad Band GSM/GPRS : 850 / 900 / 1800 / 1900 MHz

Built in RS232 to TTL or vice versa Logic Converter (MAX232)

Configurable Baud Rate

Built in Network Status LED

Input Voltage : 5V to 12V D

MAX232 IC

The MAX232 is an integrated circuit that converts signals from an RS-232 serial port to

signals suitable for use in TTL compatible digital logic circuits, so that devices works on TTL

logic can share the data with devices connected through Serial port.

Figure-10 MAX232 IC

Serial port / DB9 connector:

User just needs to attach RS232 cable here so that it can be connected to devices which

have Serial port / DB9 Connector.

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SIM (Subscriber Identity Module) Card Slot:

This on board SIM card slot provides User functionality of insert a SIM (GSM only)

card of any service provider. Process of inserting and locking SIM card into SIM card slot is

given in this manual. While inserting in and removing out SIM card from SIM card slot, User

needs to take precaution that power supply should be OFF so that after making Power supply

ON it will be easy to reinitialize with SIM for this module.

Figure-11 SIM Slot

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Circuitry in proper way

Figure- 12 GSM Based Home Security System

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WORKING

Working of GSM Home Security System

Home/ Bank/ Office security has been a major issue where crime is increasing and

everybody wants to take proper measures to prevent intrusion. In addition there was a need to

automate home so that user can take advantage of the technological advancement in such a

way that a person getting off the office does not get melted with the hot climate.

Detecting Obstacle with IR (Infrared) Sensor

The basic concept of IR (infrared) obstacle detection is to transmit the IR signal

(radiation) in a direction and a signal is received at the IR receiver when the IR radiation

bounces back from a surface of the object.

Figure- 13 IR Sensor Detection Process

Here in the figure the object can be anything which has certain shape and size, the IR

LED transmits the IR signal on to the object and the signal is reflected back from the surface

of the object. The reflected signals are received by an IR receiver. The IR receiver can be a

photodiode /photo transistor or a readymade module which decodes the signal. In order to

implement the IR obstacle detection, we need to understand the following.

We need to understand how to transmit IR signal using commercially available

electronic components.

Same way we also need to understand the IR receiver.

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IR Transmitter

In general, the basic building block of any IR transmitter is modulation of the

information signal with carrier signal, because the receiver modules which are available off-

the-shelf are made for a particular carrier frequency. So it is clear that when you chose a

particular IR receiver module, you also need to transmit the modulated wave with the same

carrier frequency of that of an IR receiver module.

IR Receiver

It is quite simple to construct an IR receiver with readily available off-the-shelf

modules. These modules are nothing but the IC packages, referred as TSOP (Thin small-

outline package). In this document, the receiver is designed for 38 kHz carrier signal; hence

the IC selected should work for the same frequency. The IC TSOP4838 will serve as a

receiver module, which is compatible with both TTL and CMOS logic. This means that we

can directly get digital signal from the receiver module and then connect it to the

microcontroller.

Once the transmitter and receiver is complete, both should be placed at a certain angle,

so that the obstacle detection happens in a proper way. This angle is nothing but the

directivity of the sensor, which is generally +/- 45 degrees.

Figure -14 IR Directivity

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Also remember, that a thick enclosure is necessary for both IR transmitter and IR

receiver, because the IR radiation may bounce back from the surrounding objects which may

not help when you want to detect obstacle in one direction. Sometimes, if you don’t have a

thick enclosure then the signal may directly reach the receiver even without having an

obstacle.

Working of GSM Module

The GSM modem is slightly different from the conventional modem. This utilizes the

GSM standard for cellular technology. Here, one end being a wired connection, receives and

transmits data. The other end is connected to a RF antenna. The GSM modem acts like a

cellular phone and transmits text and voice data. It communicates with the GSM network via

the SIM (Subscriber’s Identity Module) card. The Global System for Mobile

Communications (GSM: originally from Grouper Special Mobile) is the most popular

standard for mobile phones in the world. GSM differs significantly from its predecessors in

that both signalling and speech channels are Digital call quality, which means that it is

considered a second generation (2G) mobile phone system. This fact has also meant that data

communication was built into the system from the 3rd Generation Partnership Project

(3GPP).

When any object is detected by IR sensor then it sends the command to the

microcontroller and now microcontroller send the command to the GSM module .GSM

module have a SIM card, with the help of SIM card GSM module send the SMS on give

mobile number which is already programmed in the microcontroller

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Application

The applications of SMS/GSM Based security system are quite diverse. There are

many real life situations that require control of different devices remotely and to provide

security. There will be instances where a wired connection between a remote

appliance/device and the control unit might not be feasible due to structural problems. Major

areas where it is used as

Anti-Theft Reporting

When someone break in , Home-Guard uses GSM network to report automatically to 5

pre-set numbers: short message for control centre, short message for 3 pre-stored mobile

phone, and 1 voice call. The owner can monitor or talk to the thief.

It has 8 security region codes. We can choose some certain regions to arm or disarm.

Emergency Reporting

Under emergency situation, the house member can press SOS key on the RF remote or on

wireless Door/ Window sensor. Home-Guard also uses GSM network to report to 5 pre stored

numbers: short message for control centre, short message for 3 pre-stored mobile phone, and

1 voice call for monitoring or talking phone.

Arm/Disarm By SMS

In addition to use the RF Remote, the system allows the users to arm and disarm the

alarm system via SMS message from mobile phone. Users can also check the alarm status

anytime by simply sending an inquiry SMS message to the main unit.

Power Failure Reporting

When the main power gets cut off, Home-Guard can report to the pre-set phone numbers

immediately.

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Advantages

Worldwide Roaming: - The user can get alerts anywhere through the GSM

technology thus making the system location independent.

The system contains low cost components easily available which cuts down the

overall system cost.

The ease of deployment is due to wireless mode of communication.

GSM technology provides the benefit that the system is accessible in remote areas as

well.

The system integration is simple and is also scalable and extensible. However, the

system functionality is based on GSM technology so the techno-logical constraints

must be kept in mind

FUTURE SCOPE

In future the system will be small box combining the PC and GSM modem. The

hardware will be self-contained and cannot be prone to electric failure. This appliance will

have its own encapsulated UPS and charging system.

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CONCLUSION

Low cost, secure, ubiquitously accessible, auto-configurable, remotely controlled

solution for automation of homes has been introduced. GSM technology capable solution has

proved to be controlled remotely, provide home security and is cost-effective as compared to

the previously existing systems. The basic level of home appliance control and remote

monitoring has been implemented.

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REFERENCES

Mazidi, “The 8051 Microcontroller and Embedded Systems.

http://www.gsm-modem.de/gsm-module.html

http://www.gsm-modem.de/gsm-module.html

http://www.atmel.com/devices/at89s52.aspx