How To Make GSM Home Automation System using Arduino

Table of Contents

Overview

hey friend’s welcome in “DiY Projects Lab” In this project you’re going to build an GSM Home Automation System using arduino. where we can control the home appliances (T.V. , BULB), using the simple GSM based phone, just by sending SMS through the phone. In this Home Automantion System Project, no Smart phone is needed just the any old GSM phone you can control any home electronic appliances, from anywhere anytime .

GSM Home Automation Working Explanation

The brain of this project is an Arduino nano board which in combination with GSM module . GSM wireless communication for controlling electronics home appliances , We send some commands like “#A.Start*”, “#A.stop *” After receiving given commands by the Arduino through GSM module then Arduino send signal to relays for cut ON or OFF.

Components For GSM Based Home Automation System Using Arduino

You can get the components for Home automantion from the links below

Arduino nano x1
GSM module x1
Relay Module x1
Conneting wire and LED
Bulb
Holder

When you send SMS to GSM module by phone , then GSM receives that SMS and sends it to Arduino. then Arduino compare this command with predefined command .if it match with predefined command then then Arduino sends data to relay via relay for turning ON and OFF home appliances .

Here in this project we have used 1 zero watt bulb .

S.no.	Message	Operation
1	#A.Start*	Bulb ON
2	#A.Stop*	Bulb OFF

GSM Module

GSM module (Global System for Mobile Communications) SIM900A Model is built with Dual Band GSM/GPRS based used in many communication devices which are based on GSM technology.

There are various AT Commands like ATD to dial a call , ATA for answer a call, AT+CMGS to send the sms ,AT+CMGR to read the message etc.

We can use GSM module using these commands for any GSM Projects

Basic AT Command

1. To change sms sending mode : AT+CMGF=1

mySerial.println("AT+CMGF=1");

1	mySerial.println("AT+CMGF=1");

2. To read SMS in text mode : AT+CNMI=2,2,0,0,0

mySerial.println("AT+CNMI=2,2,0,0,0");

1	mySerial.println("AT+CNMI=2,2,0,0,0");

3. To make a call : ATD+916209403151; //replace X with number you want to call, change +60 to your country code

mySerial.println("ATD+916209403151;");

1	mySerial.println("ATD+916209403151;");

4. To disconnect / hangup call : ATH

mySerial.println("ATH");

1	mySerial.println("ATH");

5. To redial : ATDL

mySerial.println("ATDL");

1	mySerial.println("ATDL");

6. To receive a phone call : ATA

 mySerial.println("ATA");

1	mySerial.println("ATA");

GSM Based Home Automation System Using Arduino Circuit Diagram :

Connections:

GSM Sim900A :

GSM Rx to Arduino Tx.
GSM Tx to Arduino Rx.
5v to external 5v supply which can deliver up to 1 amp.
Ground to ground.

Relay :

VCC to 5V
GND to GND
Relay to D1

Programming

CODE for GSM Based Home Automantion System

#include &lt;SoftwareSerial.h&gt; // Library for using serial communication
SoftwareSerial SIM900(7, 8); // Pins 7, 8 are used as used as software serial pins

String incomingData;   
String message = "";   
int relay_pin = 1;    // Initialized a pin for relay module

void setup()
{
  Serial.begin(115200); // baudrate 
  SIM900.begin(19200); // baudrate for GSM 

  pinMode(relay_pin, OUTPUT);    
  digitalWrite(relay_pin, HIGH);  
  SIM900.print("AT+CMGF=1\r");  
  delay(100);
  
  
  SIM900.print("AT+CNMI=2,2,0,0,0\r"); 
  delay(100);
}

void loop()
{
  //Function for receiving sms
  receive_message();

  // if received command is to turn on relay
  if(incomingData.indexOf("Start")&gt;=0)
  {
    digitalWrite(relay_pin, LOW);
    message = "Led is turned ON";
    
    send_message(message);
  }
  
  // if received command is to turn off relay
  if(incomingData.indexOf("Stop")&gt;=0)
  {
    digitalWrite(relay_pin, HIGH);
    message = "Led is turned OFF";
   
    send_message(message);
  }        
}

void receive_message()
{
  if (SIM900.available() &gt; 0)
  {
    incomingData = SIM900.readString(); 
    Serial.print(incomingData); 
    delay(10); 
  }
}

void send_message(String message)
{
  SIM900.println("AT+CMGF=1");       delay(100);  
  SIM900.println("AT+CMGS=\"+916209403151\""); // Replace it with your number
  delay(100);
  SIM900.println(message);   
  delay(100);
  SIM900.println((char)26);  
  delay(100);
  SIM900.println();
  delay(1000);  
}