// Define pins
const int pirPin = 2; // PIR motion sensor pin
const int soundPin = 8; // Piezo buzzer pin

// Variables
int pirState = LOW;
int lastPirState = LOW;

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  
  // Set PIR pin as input
  pinMode(pirPin, INPUT);
  
  // Set sound pin as output
  pinMode(soundPin, OUTPUT);
}

void loop() {
  // Read PIR sensor state
  pirState = digitalRead(pirPin);
  
  // If motion detected
  if (pirState == HIGH && lastPirState == LOW) {
    // Print message
    Serial.println("Motion detected!");
    
    // Play alarm
    while (pirState == HIGH) {
      // Pulse the buzzer
      tone(soundPin, 500); // You can adjust the frequency as needed
      delay(500); // Pulse duration
      noTone(soundPin);
      delay(300); // Delay between pulses
      
      // Read PIR sensor state again
      pirState = digitalRead(pirPin);
    }
    
    // Print message when motion stops
    Serial.println("Motion stopped.");
    
    // Update last state
    lastPirState = LOW;
  }
}