/*
* UltraSonic Sensor Distance Indicator
* by Divy Srivastava
*/

// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;
const int ledPin = 11;

// defines variables
long duration;
int distance;

void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
pinMode(ledPin, OUTPUT);
}

void loop() {
// Clears the trigPin
digitalWrite(trigPin, LOW);
digitalWrite(ledPin, 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;

if(distance < 30) {
  if(distance < 8) {
    digitalWrite(ledPin, HIGH);
    delay(10);
    digitalWrite(ledPin, LOW);
    delay(10);
    digitalWrite(ledPin, HIGH);
  }
  else if(distance < 14) {
    digitalWrite(ledPin, HIGH);
    delay(100);
    digitalWrite(ledPin, LOW);
    delay(100);
    digitalWrite(ledPin, HIGH);
  }
  else if(distance < 20){
     digitalWrite(ledPin, HIGH);
     delay(300);
     digitalWrite(ledPin, LOW);
     delay(300);
     digitalWrite(ledPin, HIGH);
  }
  else {
     digitalWrite(ledPin, HIGH);
     delay(500);
     digitalWrite(ledPin, LOW);
     delay(500);
     digitalWrite(ledPin, HIGH);
  }
 }
 digitalWrite(ledPin, LOW);
}