#define TRIG_PIN 7
#define ECHO_PIN 6
#define BUZZER_PIN 8

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
}

void loop() {
  long duration, distance;
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  distance = (duration / 2) / 29.1; // Calculate distance in cm

  if (distance < 10) { // Adjust the threshold as needed
    Serial.println("Intruder detected!");
    digitalWrite(BUZZER_PIN, HIGH); // Sound the buzzer
    delay(1000); // Buzzer duration
    digitalWrite(BUZZER_PIN, LOW);
  } else {
    Serial.println("No intruders.");
    digitalWrite(BUZZER_PIN, LOW); // Ensure buzzer is off
  }

  delay(500); // Adjust the delay based on your application
}