Gsm Based Home Alarm System

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GSM based Security System using LabVIEW
Hasan Baig1, Muhammad Owais1, Muhammad Saleheen Aftab1, Kamran Shamim1 and Hamza Azeem2 Department of Electronic Engineering
NED University of Engineering & Technology, 2PAF KIET, Pakistan. (hasan.baig, ovaisbabai, saleheen2006, kamranshamim, hamzaazeem)@hotmail.com 1

Abstract- The purpose of this paper is to introduce an efficient, reliable and cost-effective security system for use at homes, offices, schools, and shops. The system automatically reports intrusion by making a call to a target mobile phone. Thus, the reporting mechanism is based on

Global System
for Mobile (GSM) and the logic is designed using LabVIEW.
Keywords: Security System, LabVIEW, GSM, Infrared.

II. HARDWARE
Infrared transmitter-receiver has been used to detect the
obstruction in infrared beam. Transmitter is placed at one end and receiver is placed at a distance (according to its range) exactly in the line of sight of transmitter at the other end. The basic component of transmitter is LM555 which generates the

desired frequency to be transmitted to receiver.

I. INTRODUCTION
A. Transmitter
One of the biggest demerits of the development in the field of technology is the innovative techniques and ideas that are
being introducing for illusory purposes. These imperfections of on going technology should be prevented through the
inventions to hinder such types of criminal or illegal activities. This project is one of such campaigns which are taking part to guard the areas that need a lot of security.
The theme of this model is illustrated in Fig. 1. The figure shows the whole system comprises of two sections. First one
is Hardware and the second one is Software (Computer).
Hardware section senses the interruption in infrared beam and generates a HIGH voltage level which in turn provided to the computer via LPT (Line Printing Terminal). This condition is detected by logic, programmed on LabVIEW causing the

computer to make a call (to a number assigned for receiving
alert) through mobile connected to computer via Bluetooth
device. The model is divided into two sections.



The transmitter circuit is quite simple and based on LM556
timer, which consists of two 555 timers. These two timers
operate independently of each other sharing only VCC &
Ground. The first timer generates a square wave of about
10ms (100 Hz) with a duty cycle of about 96% while the
second timer generates a 38 kHz square wave. This particular frequency is set in order to modulate the 100Hz signal
(Amplitude modulation) to fulfill the characteristics of the receiver module. Also the inverter has been used after the
output of the first timer. As the module can detect the square wave signal properly of around 38 kHz modulated by another
square wave signal with a minimum period of about 10 ms at a duty cycle of 4%, which can not be achieved by a 555 timer
directly as it can generate the signals with a minimum duty
cycle of 50% [1]. Thus first a square wave of 96% duty cycle is generated and then it is inverted to have a duty cycle of 4% (Fig. 2).

Hardware
Software

Fig. 1. The Block diagram of Security System.
Fig. 2. Inverted signal

III. SOFTWARE

Fig. 3. Final waveform at the transmitting end.

The RESET pin of 38 kHz timer is connected to the inverted
output of the 100 Hz signal so that the second timer works
only when the Reset pin of the timer is given high voltage.
Fig. 3 shows the final modulated waveform of the transmitter with which the IR led is driven.
B. Receiver
The module used in receiver is TSOP 1738. Its main features
include immunity to invalid signals (due to band pass filter inside the module), low power consumption and active low
output [2]. It receives the modulated infrared signals from the transmitter portion and due to demodulator inside the module; the carrier and modulated waves are separated. At the output pin we have our 100 Hz signal.

The software section of...
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