SMS based home automation using arduino and GSM Module | SIM800 | SIM900...

code:- 

#include <SoftwareSerial.h>
#include <String.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x3F, 16, 2); 
#define NO_OF_DEV 4
int devices[4] = {2 , 3 , 4 , 5}; // Device pins
int d_status[4]; // Device status
int toggle, stat;
String phone_num , buffer;
String id[4] = {"LED 1", "LED 2", "LED 3", "LED 4"};
SoftwareSerial SIM800(10 , 11);
 boolean at_flag;
void setup()
{
  Serial.begin(9600); // Serial Monitor baud rate
  SIM800.begin(9600); // GSM module baud rate
  lcd.begin();
  lcd.backlight();
  lcd.print(" SMS Based Home ");
  lcd.setCursor(0,1);
  lcd.print("   Automation ");
   delay(4000);
    gsm_init();
  for(int i = 0;i < NO_OF_DEV;i++)
  {
      pinMode(devices[i] , OUTPUT);
  }
  for(int i = 0;i < NO_OF_DEV;i++)
  {  
      digitalWrite(devices[i] , HIGH); 
  }
  for(int i = 0;i < NO_OF_DEV;i++)
     d_status[i] = 0; // All devices are OFF by default 
  toggle = 0;
  stat = 0; 
  buffer.remove(0);
  pinMode(13,OUTPUT);
  digitalWrite(13,HIGH);
  Serial.println("Device is ready.");
  lcd.clear();
  lcd.println("Device Ready");
  delay(1500);
  lcd.clear();
  lcd.print("LD1 LD2 LD3 LD4");
  
}
void loop()
{
        
    buffer = readSIM800();
    if (buffer.startsWith("\r\n+CMT: "))
    {
        phone_num = get_num(buffer);
        Serial.println("*** RECEIVED SMS *** from " + phone_num);  
        buffer.remove(0, 51); // Remove first 51 characters /// change the value from 51 to other by checking in putty ANTO (if needed)
        int len = buffer.length();
        buffer.remove(len - 2); // Remove \r\n from tail          
        Serial.println(buffer);
        Serial.println("*** END SMS ***");
    
if(buffer=="LED 1 ON")
{           d_status[0]=1;
            digitalWrite(devices[0] , !HIGH);
            lcd.setCursor(0,1);
            lcd.print("ON ");
            stat=1;
}
if(buffer=="LED 1 OFF")
{
            d_status[0]=0;            
            digitalWrite(devices[0] , !LOW);  
            lcd.setCursor(0,1);
            lcd.print("OFF");
            stat=1;
}  
if(buffer=="LED 2 ON")
{           d_status[1]=1;
            digitalWrite(devices[1] , !HIGH);
            lcd.setCursor(4,1);
            lcd.print("ON ");
            stat=1;
}
if(buffer=="LED 2 OFF")
{
            d_status[1]=0;            
            digitalWrite(devices[1] , !LOW);  
            lcd.setCursor(4,1);
            lcd.print("OFF");
            stat=1;
}
if(buffer=="LED 3 ON")
{           d_status[2]=1;
            digitalWrite(devices[2] , !HIGH);
            lcd.setCursor(8,1);
            lcd.print("ON ");
            stat=1;
}
if(buffer=="LED 3 OFF")
{
            d_status[2]=0;            
            digitalWrite(devices[2] , !LOW);  
            lcd.setCursor(8,1);
            lcd.print("OFF");
            stat=1;
}  
if(buffer=="LED 4 ON")
{           d_status[3]=1;
            digitalWrite(devices[3] , !HIGH);
            lcd.setCursor(12,1);
            lcd.print("ON ");
            stat=1;
}
if(buffer=="LED 4 OFF")
{
            d_status[3]=0;            
            digitalWrite(devices[3] , !LOW);  
            lcd.setCursor(12,1);
            lcd.print("OFF");
            stat=1;
}
    }  
    if(stat)
    {
      send_status(phone_num);
      stat = 0;
    }
}   
String readSIM800() // Save whole SMS into a string
{
    String buffers;
    char c;
    while (SIM800.available())
    {
        c = SIM800.read();
        buffers.concat(c);
        delay(10);
    }   
    return buffers;
}
String get_num(String buffer)
{
  String phone_num;
  int i = 9; // Starting index of phone number
  while(buffer.charAt(i) != '"')
  {
      phone_num.concat(buffer.charAt(i));
      i++;
  }
  return(phone_num);
}
int toggle_command(String buffers)
{
  if((buffer == "OFF") || (buffer == "off"))
     return 1;
  else if((buffer == "ON") || (buffer == "on"))
     return 0;
}
void send_status(String phone_num)
{
  SIM800.println("AT+CMGS=\""+ phone_num +"\"\r");
  delay(50);
  for(int i = 0;i < NO_OF_DEV;i++)
  {        
     if(d_status[i])
        SIM800.println(id[i] + " is ON");
     else
        SIM800.println(id[i] + " is OFF");   
     delay(100);    
  }      
  SIM800.println((char)26);
  Serial.println("Status sent.");
}
void gsm_init()
{
  lcd.clear();
  lcd.print("Finding Module..");
  at_flag=1;
  while(at_flag)
  {
    SIM800.println("AT");
    delay(1);
    while(SIM800.available()>0)
    {
      if(SIM800.find("OK"))
      at_flag=0;
    }
    
    delay(1000);
  }
  lcd.clear();
  lcd.print("Module Connected..");
  delay(1000);
  lcd.clear();
  at_flag=1;
  while(at_flag)  //
  {
    SIM800.println("AT+CNMI=2,2,0,0,0");
    delay(1);
    while(SIM800.available()>0)
    {
      if(SIM800.find("OK"))
      at_flag=0;
    }
    
    delay(1000);
  }
  lcd.clear();
  lcd.print("Open Network..");
  delay(1000);
  lcd.clear();
  
  at_flag=1;
  while(at_flag)
  {
    SIM800.println("AT+CMGF=1");
    delay(1);
    while(SIM800.available()>0)
    {
      if(SIM800.find("OK"))
      at_flag=0;
    }
    
    delay(1000);
  }
  lcd.clear();
  lcd.print("TEXT MODE..");
  delay(1000);
  lcd.clear();
  lcd.print("Disabling ECHO");
  boolean echo_flag=1;
  while(echo_flag)
  {
    SIM800.println("ATE0");
    while(SIM800.available()>0)
    {
      if(SIM800.find("OK"))
      echo_flag=0;
    }
    delay(1000);
  }
  lcd.clear();
  lcd.print("Echo OFF");
  delay(1000);
  lcd.clear();
  lcd.print("Finding Network..");
  boolean net_flag=1;
  while(net_flag)
  {
    SIM800.println("AT+CPIN?");
    while(SIM800.available()>0)
    {
      if(SIM800.find("+CPIN: READY"))
      net_flag=0;
    }
    delay(1000);
  }
  lcd.clear();
  lcd.print("Network Found..");
  delay(1000);
  lcd.clear();
}