#include <SoftwareSerial.h>
const int trigPin = 9;
const int echoPin = 10;
const int buzzer = 11;
const int ledPin = 13;
// defines variables
long duration;
int distance;
int safetyDistance;
SoftwareSerial mySerial(3, 2);

void SendSMS(String msg)
{
 mySerial.println("AT+CMGF=1"); 
  mySerial.println("AT+CMGS=\"+639602572163\""); // enter your phone number here (prefix country code)
  mySerial.print(msg);
  mySerial.write(26) ;
}


void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
pinMode(buzzer, OUTPUT);
pinMode(ledPin, OUTPUT);
Serial.begin(9600); // Starts the serial communication
//GSM module
mySerial.begin(9600);
Serial.println("Initializing..."); 
delay(1000);
mySerial.println("AT");


}

void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);
// Calculating the distance
distance= duration*0.034/2;
safetyDistance = distance;
if (safetyDistance <= 5){
  digitalWrite(buzzer, HIGH);
  digitalWrite(ledPin, HIGH);
  SendSMS("Distance is Too low");
}
else{
  digitalWrite(buzzer, LOW);
  digitalWrite(ledPin, LOW);
}
// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);
}