Sms Based Home Appliance Control Information Technology Essay

Security for homes and offices is an important aspect in the modern world; engineers are continuously developing unique security systems that take advantage of today’s technology. GSM based zone security system is one of those unique systems that provides security. This system basically works by sending a SMS to a predetermined mobile unit within a GSM network when the security is breached. It can also be logged through a pc or laptop in order to monitor the status of the security.

In today’s world various types of security systems are being used in homes, offices, cars etc. All of these systems particularly the ones used at homes mainly consist of a motion detector, a siren that triggers when it receives a signal from the motion detector, a battery, a control device and an electronic card. If there is a breach in security the motion detector sends a signal to the electronic card which in turn triggers the siren to provide the warning. This is a disadvantage as these type of warnings can only be heard if there are people present close to the source of the siren and even though some of the security systems provide a warning call to a pre-determined phone (police/security company) using the fixed land line, thieves usually disrupt the phone lines leading to the failure of such security systems.

Therefore it is important to remove the afore-mentioned shortcoming and provide a security system that is efficient, affordable and user friendly which can be achieved by taking advantage of the present technological infrastructure and hardware.

Project Aim and Objectives

The main aim of this project is to design and develop an efficient GSM based zone security system which takes advantage of the existing GSM infrastructure and hardware components that can be used at homes and offices.

The project will focus on the following specific objectives:-

To develop and enhance a security system that sends the user a SMS when the security is breached.

To test the GSM based security system on a simulator.

To build a security system that can be logged through a PC or laptop in order to monitor the status of the security.

To put forward a security system that will make it difficult to be breached by burglars.

To tell the benefits of the GSM based Zone security system compared to the other normal security system.



2.1Conceptual Literature

According to Phillips (2006) security systems provide important protection against burglary and robbery. They are being relied more and more in the world to prevent theft especially with the current high crime rate. Norman (2007) stated that there are several types of security systems but the one that users today prefer to install at homes and businesses are wireless systems as they do not have the hassle of installing a lot of wires. They are also considered to be one of the easiest of all security alarm systems to operate.

Norman (2007) highlighted that the wireless security systems use radio waves to send signals from the sensors to the control panel in order to monitor the activity within the property. The latest wireless security systems also have the ability to send data to outside sources wirelessly by using GSM.

According to Fares (2003) GSM which stands for Global systems for mobile communications is basically a cellular network in which mobile phones connect to it by searching cell in the immediate vicinity. In today’s world GSM has become one of the most essential items to us as it provides us with a communication channel that enables us to communicate with the world freely. With GSM came the implementation of SMS or text messaging as stated by Poole (2006).

Gast (2005) stated that the security systems that work with GSM infrastructure using GSM modem are known as GSM security system. In this system when there is an occurrence of security breach the user is sent a SMS notifying him/her of the security breach. It is a reliable security system but recently Nohl (2009) stated that there are fears that the GSM itself can be breached by cracking the algorithm that is responsible for the protection of the security of the GSM. This has been denied by the GSM association that represents the interests of the worldwide mobile communications industry. They have affirmed that the GSM cannot be breached and that it is not currently possible to crack the algorithm protecting the GSM.

According to Norman (2007) GSM security system consists of many other main components such as electromagnetic sensors, PIC microcontrollers, keypad etc. These components make together with the GSM modem make a very effective and reliable security system.

2.2 Related Projects

2.2.1 SMS based Home Appliance Control.

This project which was done by Anand kumar 2007 is a GSM based project in which SMS is used to control home appliances. This is done by sending the instruction through SMS which would be received by the microcontroller which then decodes the instruction and after that executes the instruction by switching on the relays attached to its port to control the appliances. In this project 8051 microcontroller was used and for software Keil u-Vision 3.0 and PRO51 programmer software was used.

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2.2.2 GSM based Voting Machine

This project was done by John Seymour (2009). It is a GSM based project in which registered voters can send their vote through SMS. This achieved by first registering the mobile number of the voter and during that registration they are given a password. So when the user is sending a SMS vote the microcontroller will read the instruction and will first run a check whether it is a registered voter or not, if it is a registered voter then it will ask for the password and verify it. If the password is correct it will accept the vote and send back an SMS acknowledgement to the voter. The microcontroller used is an 89S52 microcontroller.

2.2.3 GSM based Remote Energy Monitoring Meter

This project is a GSM based project which was done by Hussain Said (2009). This project uses GSM infrastructure to do remote monitoring and control of the energy meter located at domestic houses. This project is very useful to the Electricity Department as it would enable them to read the meter readings regularly without the need of personnel visiting each house. It basically works by using a microcontroller unit that always monitors and records the meter readings in its memory location.  Then these reading are sent to optimum location set by the Electricity Department. In this project 8051 microcontroller was used and for software Kiel u-Vision 3.0 and PRO51 programmer software was used


3.1 Technical Proposal

This project is a combination of hardware and software development. The circuit is first designed and then optimum components are selected and used for the construction of the circuit. A program is developed for the PIC microcontroller. This is done by first writing the program in C programming and then compiling it in MikroC. Several tests are done to make sure that they are all working successfully. After that the hardware development and the software development are combined. Then Visual Basic program is written for interfacing. Then an overall test is done to see if the whole project is working successfully.

Block Diagram of the Methodology used in this Project.


Project Design

Circuit Design

Develop Program for PIC

Test program on PIC Simulator

Construct Circuit


Develop VB for Interfacing

Combination of Hardware and Software

Final Testing



3.2 Equipment/ Facilities/ Programs


Breadboard is used before a prototype is built. It is used for troubleshooting and testing.

PCB: The circuit is finally built on the Printed Circuit Board (PCB).

Multimeter was used for measuring voltage, current etc and also for fault finding.

GSM modem


EAGLE (Easily Applicable Graphical Layout Editor) software: For Printed Circuit Board drawing

MikroC: PIC Simulator Software: To test the program for the PIC microcontroller

Visual Basic

3.3 Technical Description

3.3.1 PIC Microcontroller

PIC microcontroller stands for Peripheral Interface Controller according to Wilmshurt (2006). The PIC is a popular microcontroller because of several advantages such as:

Power consumption

PIC’s have much lower power consumption at 5V.


It has more accurate calibrated oscillators which help it have precise timing thus making the design more stable and efficient.


It is widely available.


The PIC microcontroller can be easily reprogrammed.

Pin direction

Most of the PIC microcontroller pins are flexible as they can be set as an input or and output thus making the design of the circuit easier.

3.3.2 Electromagnetic sensors


Figure 2.17: Electromagnetic sensor: The magnetic sensor on the left and the magnet on the right

Electromagnetic sensors are usually used on doors and in a security system they are an integral part as stated by Norman (2007). They work by sensing the movement of the doors and windows magnetically. The magnetic sensors are small in size and consist of 1 magnet and 1 magnetic sensor. Phillips (2006) stated that the magnet is placed so that the magnet and magnetic sensor are in a position to be parallel to each other. So that when the signal that is between them is interrupted the magnetic the switch is tripped and immediately it sounds the alarm


3.3.3 Keypad

Figure 2.14: 4Ã-4 matrix keypad modules

A matrix keypad is used to provide a simple data entry device for microcontroller systems. Their design is that the keys are connected in rows and columns, so that when a button is pressed a row and a column are connected. In order to read the keypad, each row is set low in turn and the state of the inputs is tested. If no button is pressed, all the inputs remain high. During the operation the rows and the columns of the keypad will be scan continuously by the microcontroller. When a key is being operated, a low on that row is detected on the column input for that key, which allows a corresponding code to be generated.

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3.3.4 RS 232

RS 232 is an electrical signaling specification which is also known as signal port is used as the gateway for data transmission’s 232 comes in 9 pins which have its own specific pin assignments. There are two types of RS 232 which is male (DB9M) and female (DB9F).

Figure 2.11: The serial port overview

Table 2.12: The definition of each serial port pins

In this project only three pins are used. Pin 2 and PIN 3 is used to receive and transmit signal with the circuit. So Pin 5 will be uses as ground.

3.3.5 GSM modem

A GSM modem is a wireless modem that works within a GSM wireless network according to Fares (2003) and he also states that the behavior of dial up modem is the same as a wireless modem. The only difference is that a dial up modem uses a fixed telephone line to transmit and receive data while a wireless modem transmits and receives data through radio waves. A GSM modem needs a SIM card in order to operate.

The GSM modem available in 2 types

External wireless modem

It is connected to the computer or a laptop a serial cable or USB cable.

PC card/PCMCIA card

It’s designed for laptops as it is slotted in a particular card slot built in the laptop.

Figure 2.19 shown the main blocks and communication principle of a wireless system using the SIEMEINS C35i GSM modem.

Figure 2.19: Main blocks in communication modem and the microcontroller.

3.3.6 AT command

An AT command is simply a set of instructions used to control a modem it the short form for Attention. Each command line starts with “AT” or “at”. A common set of standard AT commands are supported by GSM and dial up modems but the GSM modems support a more extended set of AT commands.

In order to send, read, write and delete SMS message. We can use For example AT+CMGS (send command), AT+CMGR (read command), AT+CMGW (write command) and AT+CMGD (delete command) .

Using the above mentioned commands the modem can do :-:

Reading, writing and deleting SMS message.

Sending SMS message

Monitoring the signal strength

3.3.7 SMS

SMS which is a short form for Short Message Service is used to receiving and sending message in between the mobile phone.

Fares (2003) stated that since the development of SMS it has become a very successful wireless carrier because

SMS message can be sent and ready at any time.

SMS message are supported 100% GSM mobile phones and they can be exchanged between different wireless carriers.

SMS is a suitable technology for wireless application.

The application of SMS is virtually limitless today as they are always being associated with embedded system to increase its utilization.

Examples of SMS application are:-

Person-person text message

Delivery and notification message

Used in remote system monitoring application.

3.3.8 MikroC Software

MikroC is a software programming program which used by the people in order to program and compile microcontroller.

Figure 3.3: MikroC with C programming

After created the program compile it by click the BUILD icon from the project toolbar.

Figure 3.5: After compilation successful

3.3.9 EAGLE

EAGLE also known as Easily Applicable Graphical Layout Editor is draw schematic for PCB layout. One of the main reason that EAGLE is better in drawing schematic than any other software is that it has a comprehensive component library so this helps save time as there is less need to draw up the components. The auto route function of EAGLE is also good.

Figure 3.6: Schematic drawing window

Figure 3.7: Placing components


Figure 3.9: Wire up components

Figure 3.10: Switch from schematic to board

Route toolbar

Figure 3.11: Routing toolbar


4.1 Overall Circuit Schematic Diagram

Figure 3.01: The Full Circuit Diagram of the GSM Zone based Security System

Figure 3.01 shows the overall schematic diagram of GSM Zone based intruder system. The system hardware is divided into few parts for a better explanation. They are Microcontroller (PIC16F877A) Power Supply module, Serial port communications and LCD.

4.1.1 PIC 16F877P

Figure 3.02: The microcontroller and LCD implementation

As shown in Figure 3.02 the PIC Microcontroller 16F877P was chosen because of its software support availability, low cost and high feature count.

For a reset button a push button is connected to MCLR# pin anything happens during the operation. When the PIC is ON and the MCLR# pin is connected to ground RESET occurs.

A 4MHz oscillator is used which is widely popular in PIC circuits due to the importance of timing and clocking. Capacitor C3 and C4 is used to filter the oscillator signal. The resistor R11 is used for current limiting. The complete pin allocation shown in table 3.03.






Connected to reset switch and Vcc (+5V)





















Connected to Buzzer



Connected to Buzzer






Vcc (+5V)





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Connected to 4MHz Oscillator



Connected to 4MHz Oscillator















Connected to LCD pin 11



Connected to LCD pin 12



Connected to LCD pin 13



Connected to LCD pin 14









Connected to MAX 232



Connected to MAX 232



Connected to LCD pin 4



Connected to LCD pin 6






Connected to output



Connected to ground



Connected to VCC (+5V)



Connected to Keypad pin 1



Connected to Keypad pin 2



Connected to Keypad pin 3



Connected to Keypad pin 4



Connected to Keypad pin 5



Connected to Keypad pin 6



Connected to Keypad pin 7



Connected to Keypad pin 8

Table 3.03: The PIC16F877P pin allocation

4.1.2 Power supply module

Figure 3.04: Voltage regulator used in system

Designing a power supply module will be more complex and heavy as it consist of a step down transformer. By considering the fact, the required input voltage is supplied directly from a 9V battery. The figure 3.04 is the voltage regulator LM 7805 used to regulate the 9V input voltage from the battery. The 9V voltage will be step down and regulate to 5V.The output obtain from this power supply circuit are 9V (V+) and 5V (Vcc) DC voltage. These voltages value are based on the requirement of each module especially PIC 16F877P.The capacitor 220µF is a bypass capacitor used for filtering the regulated voltage. The output voltage of this module will be supplied to PIC 16F877P, Liquid Crystal Display (LCD) and MAX 232.

4.1.3 Serial Port communication

Figure 3.05: The serial port communication component

In the serial port communication shown above, MAX 232 is connected in between modem and the circuit to work as buffer .It works by shifting the signal voltage level according to the requirement. The connection is figure above are based on the datasheet. The serial port pin 3(Tx) in RS 232 is connected with MAX 232 T1 OUTPUT which is pin 14.This connection is used to transmit data from modem to microcontroller. Hence the serial port pin 2(Rx) in RS 232 is connected with MAX 232 R1 IN input pin 13.The purpose of connection is for receiving data from microcontroller to modem.

The capacitors are chosen as 10µF and not 1µF as stated in datasheet because the value worked well when testing was done.

4.1.4 LCD

Figure 3.06: The LCD used in the system

The LCD is used to display the status of the GSM Zone based Security System. The type of LCD used is a 16 character line length in two line version JHD162A series LCD, which conform to a standard interface specification. Pins 1 and 2 are the power supply lines, whereby pin 1 is connected to ground and pin 2 to Vcc (+5V). Pin 3 is a control pin, which is used to alter the contrast of the display. This pin is connected to a variable resistor to alter the contrast by altering the resistance value. Pin 4 is the register select (RS line) connected to pin 27 of PIC 16F877P .Pin5 which will be the Read/Write line is connected with pin 3 of LCD itself. Where else the pin 6 which function as enable line connected to pin 28 of PIC 16F877P.The data line pin 11 to 14 of LCD is connected with pin 19,pin20,pin21 and pin 22 of PIC 16F877P.

4.1.5 Relay

Figure 3.07: Relay used in the system

Relay are devices which allow low power circuits to control the high circuits or instruments. Figure 3.07 shows the basic relay driver circuits used in GSM Zone based Security System. A 9V DC voltage been feed through the coil. A NPN BC547 transistor is being used to control the relay. The transistor is turn ON when the signal is feed through the pin 30 of the PIC. Once the transistor turns ON it will turn ON the relay. A diode IN4148 is connected across the relay coil to protect the transistor.

4.1.6 Software Architecture

The PIC used in the system is programmed by using the C language. C language is one of the several programmer language commonly used to create a list of instruction to control the system. Figure 3.08 shows the flow of the constructed program in this project. As what has been discussed in chapter 2.3 the C language need to go through the compiling stage before being stored in the PIC. The MIKRO C compiler is used to compile the program of the system. Hence, the compiled program will be stored in PIC by using the PIC KIT 2 programmer. The compiling and storing process will be show in detail in appendices.

Figure 3.08: Flow of the program in the intruder system

4.1.6 PCB Schematic Layout

Fig 4.3.1 PCB Schematic Layout

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