Gsm Based Home Security

Published on May 2016 | Categories: Documents | Downloads: 47 | Comments: 0 | Views: 421
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The objective of the project is to design a home security system which detects presence of intruders, occurrence of fire as well as power failure and alerts the user through the use of short messaging service (SMS) of mobile phones.


The GSM based home security system utilizes different modules which act concurrently in order to monitor the domestic situation and alert the resident in case of emergency. A number of different sensor modules are utilized to monitor intruders, fire as well as power failure. The micro-controller module processes the information that it receives from the sensor modules and decides the action to be taken. The LCD, buzzer and GSM modules alert the user regarding the emergency situation. The output of these three modules depends on the micro-controller module.

The Sensor Module

Display Module

GSM Module

Controller Module

y The sensor module consists of a group of sensor for


The display module is used to display the electrical information so that it can be easily understood by the user. A 16*2 Liquid Crystal Display is used as the display module in the system. It provides status updates to the user so that the user is aware whether the system is in monitoring state or it has detected some emergency situation

y GSM MODEM- it transmit the sms on receiving a

microcontroller command to the specified mobile number. y LINE DRIVER- it converts the TTL logic into RS 232 logic. The PC connectors are used to get and send the information through PCs ports.

y Microcontroller is used to monitor all the operations

in the system. y It is a 40 pin IC. It takes the information and performs operation according to present information. y In 40 pin AT89C51, there are four ports designated as P1, P2, P3 and P0. All these ports are 8-bit bi-directional ports, i.e., they can be used as both input and output ports. These ports are also bit addressable and so their bits can also be accessed individually.

y The system is connected to a power supply sytem y As soon as the connection are completed, the GSM modem sends a message to the user stating System On . y At the same time, the LCD displays a welcome screen stating Home Security System y After that, the LCD displays a status message "Monitoring . During this time, the system is monitoring the status of all the sensors but has not yet encountered an emergency condition y When any sensor detects an emergency state, for example, if there is an occurrence of fire, the thermistor sends a signal to the MCU

‡The MCU then sends information to the GSM modem to send a text message to the user as well as concerned authorities stating "Fire occurred at address xx´ ‡Simultaneously, the LCD starts to display an emergency message of ³Fire´ and the buzzer also starts ringing ‡Similarly, in case an intruder is detected or power failure occurs, the LCD, the buzzer and the GSM modem operate simultaneously to alert the user and the concerned authorities regarding the same

A power supply can by broken down into a series of blocks, each of which performs a particular function. In this project, we are generating a 5V power supply .

y FIRE ALARM In this fire alarm circuit, a thermistor works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. At normal temperature, the resistance of the thermistor is approximately 10 kilo-ohms, which reduces to a few ohms as the temperature increases beyond 100°C. When thermistor becomes hot, it provides a low-resistance path to extend positive voltage to the base of transistor via diode and resistor. Diode provides a high-resistance (10-kilo-ohm) path when the thermistor connected to the positive supply cools down. It also stops the conduction of transistor. The circuit works off a 6V-12V regulated power supply. LED is used to indicate that power to the circuit is switched on.

In the intruder circuit the anode of the transmitter and receiver (detector) are connected to the 5 V power supply and cathode of the emitter is connected to ground whereas that of receiver is connected to the ground and trigger pin of the 555 timer i.e. pin no. 2. When the bias voltage is applied to the infrared circuit, the transmitter emits the Infra-Red ray (IR). This ray receives the receiver (detector) and produced an output signal at pin 3 of the 555 timer.

The power failure alarm circuit that produces an alarm whenever the mains supply fails . In this circuit, when power failure occurs, a pulse is sent to the P2.0 of the microcontroller unit which in turn perform the task of turning on the buzzer and at the same time displaying message on LCD. In Addition to this, a signal is sent to GSM modem to send a message to a remote mobile that power failure has occurred.

y The 44780 standard requires 3 control lines as well as

either 4 or 8 I/O lines for the data bus. The user may select whether the LCD is to operate with a 4-bit data bus or an 8-bit data bus. If a 4-bit data bus is used the LCD will require a total of 7 data lines (3 control lines plus the 4 lines for the data bus). If an 8-bit data bus is used the LCD will require a total of 11 data lines (3 control lines plus the 8 lines for the data bus). y The three control lines are referred to as EN, RS, and RW

We have used an 8-bit data bus and is using 11of the 8051's I/O pins to interface with the LCD.

y The GSM modem is a highly flexible plug and play quad band GSM modem for direct and easy integration to RS232. Supports features like Voice, Data/Fax, SMS, GPRS and integrated TCP/IP stack. Here sms feature of GSM modem is used. INTERFACES:y RS-232 through D-TYPE 9 pin connector, Serial port baud rate adjustable 1200 to115200 bps (9600 default) y Power supply through DC socket y SMA antenna connector y Push switch type SIM holder y LED status of GSM / GPRS module

y Insert SIM card: Press the yellow pin to remove the tray

from the SIM cardholder. After properly fixing the SIM card in the tray, insert the tray in the slot provided. y Connect Antenna: Screw the RF antenna on the RF cable output provided. y Connect RS232 Cable: (Cable provided for RS232 communication) Default baud rate is 9600 with 8-N-1, no hardware handshaking. Cable provided has pins 7 and 8 shorted that will set to no hardware handshaking. In you need hardware handshaking the pins 7-8 can be taken for signaling.



y 8051 act as a controlling block to monitor the working

of all the sensors and taking the necessary action.

y The idea can be implemented to monitor all the

devices inside the house . y Using network interface all the houses in a city can be linked to a common database of the local authorities and any breach can be detected and appropriate action taken accordingly. y The project can be extended to monitor the power efficiency of each device and calculate the energy requirement in a house.

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