// Define Pin Allocations
const int pirSensorPin = 7;  // PIR motion output pin
const int greenLedPin = 2;   // Secure indicator
const int redLedPin = 3;     // Alarm indicator
const int buzzerPin = 4;     // Audible siren

// Variable to track motion state
int motionStatus = LOW;

void setup() {
  // Setup output devices
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  
  // Setup input device
  pinMode(pirSensorPin, INPUT);
  
  // Open communication to Serial Monitor
  Serial.begin(9600);
  Serial.println("--- PIR Motion Security System Active ---");
}

void loop() {
  // Read the digital state of the PIR sensor
  motionStatus = digitalRead(pirSensorPin);
  
  if (motionStatus == HIGH) {
    // MOTION DETECTED!
    digitalWrite(greenLedPin, LOW);   // Kill secure light
    digitalWrite(redLedPin, HIGH);    // Trigger alert light
    
    // Play an alternating security siren (800Hz to 1200Hz)
    tone(buzzerPin, 1200, 150);
    delay(150);
    tone(buzzerPin, 800, 150);
    
    Serial.println("[INTRUSION ALERT] Motion detected in the secured zone!");
  } 
  else {
    // SYSTEM SECURE
    digitalWrite(greenLedPin, HIGH);  // Keep secure light alive
    digitalWrite(redLedPin, LOW);     // Ensure alert light is dead
    
    noTone(buzzerPin);                // Silence the siren
  }
  
  // Small delay to allow simulation processing
  delay(100);
}