/*
* Ultrasonic Sensor HC-SR04 and Arduino Tutorial
*/
	// defines pins numbers
const int trigPin = 2;
const int echoPin = 4;
const int buzzer=5;
const int led=19;
const int irSensorPin = 2; 
const int ledPin = 13;     
	// defines variables
long duration;
int distance;
int Distance;

void setup() 
{
pinMode(trigPin, OUTPUT); 	// Sets the trigPin as an Output
pinMode(echoPin, INPUT); 
pinMode(led, OUTPUT); 	// Sets the echoPin as an Input
//Serial.begin(9600); 		// Starts the serial communication

 pinMode(irSensorPin, INPUT); 
  pinMode(ledPin, OUTPUT);     
  Serial.begin(9600);     
}
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");
if(distance<250){
  tone(buzzer,1000);
  digitalWrite(led ,HIGH);
  delay(1000);
  noTone(buzzer);
  // digitalWrite(led, LOW);
   delay(250);
}
else
{
   digitalWrite(led, LOW);
}
//delay(500);  //500 m.sec = 0.5 sec
}
//  int obstacleDetected = digitalRead(irSensorPin); 

//   if (obstacleDetected == HIGH) {
//     digitalWrite(ledPin, HIGH); 
//     Serial.println("Obstacle detected!");
//   } else {
//     digitalWrite(ledPin, LOW); 
//     Serial.println("No obstacle detected.");
//   }

//   delay(1000); 
// }