const int trigPin = 9;
const int echoPin = 10;
const int buzzer = 11;
const int ledPin = 13;

long duration;
int distance;
int printCounter = 0; 
const int printInterval = 10; 

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(20);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  if (distance <= 200) {
    tone(buzzer, HIGH);
    digitalWrite(ledPin, HIGH);
    if (printCounter % printInterval == 0) { 
      Serial.println("Intruder Alert");
      Serial.println(distance);
    }
  } else {
    noTone(buzzer); 
    digitalWrite(ledPin, LOW);
    if (printCounter % printInterval == 0) { 
      Serial.print("Distance: ");
      Serial.println(distance);
    }
  }

  printCounter++; 
  if (printCounter >= printInterval) {
    printCounter = 0; 
  }
  delay(100); 
}