program.ino

void Connection()
{
  mySerial.println("AT");
  delay(1000);

  mySerial.println("AT+CPIN?");
  delay(1000);

  mySerial.println("AT+CREG?");
  delay(1000);

  mySerial.println("AT+CGATT?");
  delay(1000);

  mySerial.println("AT+CIPSHUT");
  delay(1000);

  mySerial.println("AT+CIPSTATUS");
  delay(2000);

  mySerial.println("AT+CIPMUX=0");
  delay(2000);
 
  ShowSerialData();
 
  mySerial.println("AT+CSTT=\"internet\"");//start task and setting the APN,
  delay(1000);
 
  ShowSerialData();
 
  mySerial.println("AT+CIICR");//bring up wireless connection
  delay(3000);
 
  ShowSerialData();
 
  mySerial.println("AT+CIFSR");//get local IP adress
  delay(2000);
 
  ShowSerialData();
 
  
  
} 

 void Send2thingspeak(float PPM,float Gasvalue)
{
  mySerial.println("AT+CIPSPRT=0");
  delay(3000);
 
  ShowSerialData();
  
  mySerial.println("AT+CIPSTART=\"TCP\",\"api.thingspeak.com\",\"80\"");//start up the connection
  delay(6000);
 
  ShowSerialData();
 
  mySerial.println("AT+CIPSEND");//begin send data to remote server
  delay(4000);
  ShowSerialData();
  
    String str="GET http://api.thingspeak.com/update?api_key=T6JWVAB9BXBZRWUV&field1=" + String(PPM)+"&field2=" + String(Gasvalue);
  mySerial.println(str);//begin send data to remote server
  delay(4000);
  ShowSerialData();

  mySerial.println((char)26);//sending
  delay(5000);//waitting for reply, important! the time is base on the condition of internet 
  mySerial.println();
 
 
}
void ShowSerialData()
{
  while(mySerial.available()!=0)
    Serial.write(mySerial.read());
}