Door Security System Using Gboard Pro

/*************************************************************
 * Equivalent arduino pins of GboardPro
 * EB0 - A0    for magnetic sensor
 * TX1 - 18    for status led
 * more details of Gboard: https://www.itead.cc/wiki/Gboard_Pro
 ************************************************************/
 
#include <GSM_Shield.h>

char number[]="+91xxxxxxxxxx";  //Destination number 

GSM gsm;

int error;

int doorSwitch_sensor = A0;
byte cnt = 1;

#define statusled 18
#define simpwr 46
#define simrst 47

void setup() 
{
  pinMode(statusled, OUTPUT);
  digitalWrite(statusled, LOW); //logic low means ON
  delay(500);
  
  Serial.begin(9600);
  pinMode(doorSwitch_sensor, INPUT);
  pinMode(simpwr, OUTPUT);
  pinMode(simrst, OUTPUT);

  Serial.println("sim Power ON"); 
  digitalWrite(simpwr,HIGH);
  delay(1000);
  
  digitalWrite(statusled, HIGH); //logic low means ON
  delay(1000);
  digitalWrite(statusled, LOW); //logic low means ON
  delay(500);
  digitalWrite(statusled, HIGH); //logic low means ON
  delay(1000);
  digitalWrite(statusled, LOW); //logic low means ON
  delay(500);
  
  //digitalWrite(simrst,HIGH);
  //delay(2000);
  Serial.println("system startup"); 
  gsm.TurnOn(9600);          //module power on
  gsm.InitParam(PARAM_SET_1);//configure the module  
  gsm.Echo(0);               //enable AT echo 
  digitalWrite(statusled, LOW); //logic low means ON
  delay(1);
  sendSMSFunction("Device ON!");
  Serial.println("Device Ready");
}


void loop()
{  
  int i=0;
  
  int buttonState = digitalRead(doorSwitch_sensor);
  if((buttonState==1) && (cnt==1)){
      //Serial.println("Door Opened!");
      sendSMSFunction("Door Opened!");
      cnt = 0;
    }

  if((buttonState == 0) && (cnt==0)){
      //Serial.println("Door Closed!");
      sendSMSFunction("Door Closed!");
      cnt = 1;    
    }
  // print out the state of the button:
  Serial.println(buttonState);
  delay(1000);        // delay in between reads for stability     
}  

void sendSMSFunction(char msg[]){
      digitalWrite(statusled, HIGH); //logic low means ON
      delay(500);
      digitalWrite(statusled, LOW); //logic low means ON
      delay(100);
      digitalWrite(statusled, HIGH); //logic low means ON
      delay(500);
      digitalWrite(statusled, LOW); //logic low means ON
      delay(100);
      digitalWrite(statusled, HIGH); //logic low means ON
      delay(500);
      
      strcpy(text, msg);
      Serial.print("Send SMS to ");
      Serial.print(number);
      Serial.print("   ");
      Serial.println(text);
      error=gsm.SendSMS(number,text);  
      if (error==0)  //Check status
      {
         Serial.println("SMS ERROR \n");
      }
      else
      {
         Serial.println("SMS OK \n");             
      }
  
  }