const int trigPin = 22;
const int echoPin = 23;
const int buzzerPin = 2;
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(2, OUTPUT);
Serial.begin(9600); 		// Starts the serial communication
}


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;

if (distance < 100) {
	// digitalWrite(2, HIGH);
	tone(buzzerPin, 10000);
} else {
	noTone(buzzerPin);
	// digitalWrite(2, LOW);
}
	// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.print(distance);
Serial.println("cm");
delay(500);  //500 m.sec = 0.5 sec
}