//use SoftwareSerial library file for displaying result 
//on serial monitor 
#include<SoftwareSerial.h>

//digital pin 2 for trigger
const int triggerpin=2;
//digital pin 3 for echo
const int echopin=3;
//digital pin 4 for buzzerpin
const int buzzerpin=4;

//use two variables "dur" for duration  
long dur;
//and "dist" for calculating distance
long dist;

void setup(){
  //define the pins under setup block
   pinMode(triggerpin,OUTPUT);
   pinMode(echopin,INPUT);
   pinMode(buzzerpin,OUTPUT);
   //define baudrate 9600 for communication
   Serial.begin(9600);
}
 
void loop(){
  //first make sure that trigger pin is low  
  digitalWrite(triggerpin,LOW);
  delayMicroseconds(2);
  //now make trigger pin high for 10 microseconds
  digitalWrite(triggerpin,HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerpin,LOW);
  //calculate duration of sound pulse by making echo pin high
  dur=pulseIn(echopin,HIGH);
  delayMicroseconds(30);
  dist=(dur*0.034)/2;//since speed of sound in air is 343.2 m/s.
  //condition for object detection
  if(dist<10){
    digitalWrite(buzzerpin,HIGH);
    Serial.println("Object detected ");
  }else{
    digitalWrite(buzzerpin,LOW);
    Serial.println("object Not detected ");
  }
  delay(500);
}
