#include <SoftwareSerial.h>
#define gasPin A0
#define buzzerPin 12
SoftwareSerial SIM900A(10, 11);
int sensorValue = 0;
void setup()
{
  pinMode(buzzerPin, OUTPUT);
  pinMode(gasPin, INPUT);
  digitalWrite(buzzerPin, LOW);

  SIM900A.begin(9600);
  Serial.begin(9600);
  Serial.println ("SIM900A Ready");
  delay(15000);
  SendMessage();
  SendMessage2();
  SendMessage3();
}
void loop() {
  sensorValue = analogRead(gasPin);
  Serial.println(sensorValue);
  if (sensorValue > 85) {
    digitalWrite(buzzerPin, HIGH);
    SendMessage();
    SendMessage2();
    SendMessage3();
    digitalWrite(buzzerPin, LOW);
    delay(1000);
  }
}
void SendMessage()
{
  Serial.println ("Sending Message");
  SIM900A.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);
  Serial.println ("Set SMS Number");
  SIM900A.println("AT+CMGS=\"+966563344684\"\r"); //Mobile phone number to send message
  delay(1000);
  Serial.println ("Set SMS Content");
  SIM900A.println("Gas Alert !! Warning!!");// Messsage content
  delay(100);
  Serial.println ("Finish");
  SIM900A.println((char)26);// ASCII code of CTRL+Z
  delay(1000);
  Serial.println ("Message has been sent ->SMS Selesai dikirim");
}
void SendMessage2()
{
  Serial.println ("Sending Message");
  SIM900A.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);
  Serial.println ("Set SMS Number");
  SIM900A.println("AT+CMGS=\"+966566437482\"\r"); //Mobile phone number to send message
  delay(1000);
  Serial.println ("Set SMS Content");
  SIM900A.println("Gas Alert !! Warning!!");// Messsage content
  delay(100);
  Serial.println ("Finish");
  SIM900A.println((char)26);// ASCII code of CTRL+Z
  delay(1000);
  Serial.println ("Message has been sent ->SMS Selesai dikirim");
}
void SendMessage3()
{
  Serial.println ("Sending Message");
  SIM900A.println("AT+CMGF=1");    //Sets the GSM Module in Text Mode
  delay(1000);
  Serial.println ("Set SMS Number");
  SIM900A.println("AT+CMGS=\"+966509477638\"\r"); //Mobile phone number to send message
  delay(1000);
  Serial.println ("Set SMS Content");
  SIM900A.println("Gas Alert !! Warning!!");// Messsage content
  delay(100);
  Serial.println ("Finish");
  SIM900A.println((char)26);// ASCII code of CTRL+Z
  delay(1000);
  Serial.println ("Message has been sent ->SMS Selesai dikirim");
}