int inputPin = 2; // Pin for the motion sensor input
int pirState = LOW; // Initial state for motion detection
int val = 0; // Variable to store the input state
int pinSpeaker = 9; // Pin connected to the buzzer
int ledPin = 10; // LED pin

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(inputPin, INPUT);
  pinMode(pinSpeaker, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  val = digitalRead(inputPin);
  if (val == HIGH) { // If motion is detected
    digitalWrite(ledPin, HIGH); // Turn on LED
    delay(150); // Short delay

    if (pirState == LOW) {
      Serial.println("Metal Detected!");
      pirState = HIGH;
      // Play a tone when motion is detected
      playTone(100, 5); // Play tone for 100ms with a frequency of 5Hz
    }
  } else {
    digitalWrite(ledPin, LOW); // Turn off LED
    delay(300); // Longer delay

    if (pirState == HIGH) {
      Serial.println("No Metal Detected!");
      pirState = LOW;
    }
  }
}

void playTone(long duration, int freq) {
  duration *= 1000;
  int period = (1.0 / freq) * 1000000;
  long elapsed_time = 0;
  while (elapsed_time < duration) {
    digitalWrite(pinSpeaker, HIGH);
    delayMicroseconds(period / 2);
    digitalWrite(pinSpeaker, LOW);
    delayMicroseconds(period / 2);
    elapsed_time += (period);
  }
}