12-03-2012, 01:58 PM
GSM Based Home Security System
Abstract
Home 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.
Introduction
The project is aimed at developing the security of Home against Intruders , Gas Leak and Fire . In any of the above three cases any one met while you are out of your home than the device sends SMS to the emergency no provided to it.
The report consists of a background into the area of 8051 microcontroller and mobile communication, how they are interfaced to each other and AT (Attention) commands set used in communication.
HARDWARE USED
1. AT command supporting GSM mobile phone.
2. 89S52 Microcontroller
3. Max 232 IC.
4. Relays
5. Relay driver IC ULN 2803
6. Voltage regulator 7805.
7. Diode IN4007
8. GSM Phone
9. LPG Gas Sensor
operations
in this project we interfaced 8051 microcontroller with Motorola’s C168 GSM mobile phone to decode the received message and do the required action. The protocol used for the communication between the two is AT command.
The microcontroller pulls the SMS received by phone, decode it, recognizes the
Mobile no. and then switches on the relays attached to its port to control the appliances. After successful operation, controller sends back the acknowledgement to the user’s mobile through SMS.
AT-Command set
The following section describes the AT-Command set. The commands can be tried out by connecting a GSM modem to one of the PC’s COM ports. Type in the test-command, adding CR + LF (Carriage return + Line feed = \r\n) before executing. Table gives an overview of the implemented AT-Commands in this application. The use of the commands is described in the later sections.
