GSM SMS Based Home Appliance Control System

Designed for control application, this project provides 4 relay outputs. It can be used in various applications. Connection to the relay outputs is via “pluggable type” screw terminal blocks. The project presented here is based on world’s most powerful intel’s mcs-51 family of microcontroller atmel at89c51. In this project we are using AT 89C52 microcontroller.

OPERATION

To switch on devices, You can send sms to the device as ON1 ON2 ON3 and so on. To switch off devices send sms as OFF1 OFF2 OFF3 and so on .

To check status of all the devices send  S.

To switch on or off devices and know the status send sms as ON1 OFF2 ON4  ON3 S.

Communication between SIM300 modem and microcontroller takes place via serial port using Sim300 AT command set. Which can be downloaded from the official SIMCOM site.

Some are given here, can be tried on PC using hyper terminal.

SMS commands

Set SMS system into text mode, as opposed to PDU mode.

AT+CMGF=1

OK

Send an SMS to myself.

AT+CMGS=”+9196xxxxxxxx”

> This is a test

+CMGS: 199

OK

Unsolicited notification of the SMS arriving

+CMTI: “SM”,2

Read SMS message that has just arrived.

Note: the number should be the same as

that given in the +CMTI notification.

AT+CMGR=23

+CMGR: “REC UNREAD”,”+9196xxxxxxxx”,,”12/11/01,15:45:24+22″

This is a test

OK

Source From: hobbyprojects.net