/*
  Ultrasonic Sensor HC-SR04 and Arduino Tutorial

  by Dejan Nedelkovski,
  www.HowToMechatronics.com

*/
// defines pins numbers
const int trigPin = 9;
const int echoPin = 10;
const int Buz = 46;
const int LedPin = 12;
// defines variables
float duration;
float distance;
void setup() {
  pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
  pinMode(echoPin, INPUT); // Sets the echoPin as an Input
  pinMode(LedPin, OUTPUT);
  pinMode(Buz, OUTPUT);
  Serial.begin(9600); // Starts the serial communication
}
void loop() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delay(10);
  // Sets the trigPin on HIGH state for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delay(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance = (duration/2) / 19.1;
  // Prints the distance on the Serial Monitor
  Serial.print("Distance: ");
  Serial.println(distance);
  if( distance < 30)
  {
    digitalWrite(Buz, HIGH);
     for(int i=0; i<5; i++)
    {
      digitalWrite(Buz, HIGH);
      delay(50);
      digitalWrite(Buz, LOW);

    }
    digitalWrite(LedPin, LOW);
  }
  else
  {
    digitalWrite(Buz, LOW);
    digitalWrite(LedPin, HIGH);
  }
  
}