const int trigPin = 2;
const int echoPin = 4;
const int buzzerPin=15;

	// 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
Serial.begin(9600); 		// Starts the serial communication
pinMode(buzzerPin, OUTPUT);
pinMode(5, OUTPUT);
}

void loop() 
{	// Clears the trigPin
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 microsec.
duration = pulseIn(echoPin, HIGH);
	// Calculating the distance
distance= (duration*0.034)/2;
	// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.print(distance);
Serial.println("cm");
delay(500);  //500 m.sec = 0.5 sec

if(distance>200){
  tone(buzzerPin, 31);
 
  delay(1000);
  
  noTone(buzzerPin);
 
  delay(1000);

  
  delay(2000);
   digitalWrite(5,HIGH);
  delay(50); 
   digitalWrite(5,LOW);
   delay(50); 
}else if(distance<100){
  tone(buzzerPin, 31);
 
  delay(1000);
  
  noTone(buzzerPin);
 
  delay(1000);

  
  delay(2000);
   digitalWrite(5,HIGH);
  delay(50); 
   digitalWrite(5,LOW);
   delay(50); 
}
}