/*
 Voltaat learn (http://learn.voltaat.com/)
 Link for full tutorial:

 Tutorial: Send a message from Arduino to your phone

 The function of this code is to send an SMS message,
 "This message from your Arduino Uno,"
 from your Arduino to your cell phone,
 The code is simple and straightforward;
 it may help you with more complex applications.

 Connections from the Arduino to the breadboard:
 • Arduino GND pin → Breadboard ground line
 • Arduino 5V pin → Breadboard 5V line

 Connections from the sim900 GSM module:
 • TWO GND pin→ Breadboard ground line
 • TXD pin → Arduino pin 7
 • RXD pin → Arduino pin 8

 Connections from the push button:
 • First pin→ Breadboard 5v line
 • Second pin→ Arduino pin 2
 • Second pin→10KΩ resistor → Breadboard ground line
*/

//Allows serial communication on other digital pins of an Arduino board
#include "SoftwareSerial.h"

//Define push button to arduino digital pin 2
#define pushButton 2

//Configure software serial port with digital pins 7,8 (TR,RX)
SoftwareSerial SIM900(7, 8);

//Commands inside void setup run once
void setup() {

 //Arduino communicates with SIM900 GSM shield at a baud rate of 9600 (9600 bits per second)
 SIM900.begin(9600);

 //Start the serial monitor at 9600 baud rate (9600 bits per second)
 Serial.begin(9600);

 //pushButton is defined as an input
 pinMode(pushButton, INPUT);

 // Give time to your GSM shield log on to network
 //delay(20000);


}

//Commands inside void setup run forever
void loop()
{
 //If you press the push button
 if (digitalRead(pushButton) == HIGH) {

   // Send the SMS
   sendSMS();
   Serial.println("This Message from your Arduino Uno");
   delay(15000);
 }
}

void sendSMS() {
 // AT command to set SIM900 to SMS mode
 SIM900.print("AT+CMGF=1\r");
 delay(100);

 //Replace the X's WITH THE recipient's mobile number - use the international fromat
 SIM900.println("AT+CMGS=\"+201068421369\"");
 delay(100);

 //Send "This Message from your Arduino Uno" to your phone nubmer
 SIM900.println("This Message from your Arduino Uno");
 delay(100);
 //End AT command with a ^Z, ASCII code 26
 SIM900.println((char)26);
 delay(100);
 SIM900.println();
 //Give module time to send SMS
 delay(5000);
}