/*
  MSJ Researchers World
  Date - 18th NOV 2024
  Mentor - Mr. Siranjeevi M
  Contact - 7373771991
*/

// Define pins for PIR sensor and buzzer
const int pirPin = 3;    // PIR sensor output pin
const int buzzerPin = 5; // Buzzer pin

// Variable to store PIR sensor state
int pirState = LOW;

void setup() {
  // Initialize pins
  pinMode(pirPin, INPUT);
  pinMode(buzzerPin, OUTPUT);

  // Initialize serial communication (optional for debugging)
  Serial.begin(9600);
}

void loop() {
  // Read PIR sensor state
  pirState = digitalRead(pirPin);

  // If motion is detected
  if (pirState == HIGH) {
    Serial.println("Motion detected!");

    // Generate emergency alert tone
    for (int i = 0; i < 3; i++) { // Repeat the alert tone 3 times
      tone(buzzerPin, 1000, 500); // Frequency: 1000 Hz, Duration: 500ms
      delay(600);                 // Wait slightly longer than tone duration
      tone(buzzerPin, 1500, 500); // Frequency: 1500 Hz, Duration: 500ms
      delay(600);                 // Wait slightly longer than tone duration
    }

    delay(1000); // Cooldown period before sensing again
  } else {
    // No motion detected
    Serial.println("No motion");
    noTone(buzzerPin); // Ensure the buzzer is off
  }

  delay(100); // Short delay for sensor stabilization
}