int echopin = 2;    //to receive signal which are coming back from object after reflection
int trigpin =3;     //to send ultrasonic signal towards any objects
int Time;           
int Distance;       

void setup() {
  // put your setup code here, to run once:
pinMode(trigpin, OUTPUT);   
pinMode(echopin, INPUT);    
//9600 : It is the transfer rate(speed), means at 9600 rate transferring of data 
//will happen between the connected devices
Serial.begin(9600);  //starts transfering data between 2 devices(sensor and arduino)
Serial.print("Ultrasonic Distance:..."); 
}

void loop() 
{
  // put your main code here, to run repeatedly:
digitalWrite(trigpin, LOW); //stop the functioning of ultrasonic sensor
digitalWrite(trigpin, HIGH); //starts the functioning of ultrasonic sensor  
Time =pulseIn (echopin,HIGH);
//pulseIn() to get the time taken by sound wave to reflect back after hitting the object
Distance= Time * 0.0172;   //number 0.0172 is constant(speed)
Serial.print("Time:"); //print time in msec
Serial.print(Time);
Serial.print(" microseconds"); 
delay(1000); 
Serial.print(",Distance:" ); //print distance in cm
Serial.print(Distance);
Serial.println("cm");
delay(1000); 
}

//OUTPUT- Click on sensor then you can edit the Distance value to check new Time calculation
// If the distance is higher the duration is higher and vice versa.