#include <LiquidCrystal.h>
#include <Servo.h>

// Pin definitions
#define PIR_PIN 2
#define RELAY_PIN 8
#define SERVO_PIN 9

// Initialize LCD (RS, E, D4, D5, D6, D7)
LiquidCrystal lcd(12, 11, 5, 4, 3, 7);

// Initialize Servo
Servo doorServo;

// Variables
bool motionDetected = false;
bool systemArmed = true;
int servoLockPos = 0;     // Locked position
int servoUnlockPos = 90;  // Unlocked position

void setup() {
  // Initialize serial communication
  Serial.begin(9600);
  
  // Initialize pins
  pinMode(PIR_PIN, INPUT);
  pinMode(RELAY_PIN, OUTPUT);
  
  // Initialize servo
  doorServo.attach(SERVO_PIN);
  doorServo.write(servoLockPos); // Start in locked position
  
  // Initialize LCD
  lcd.begin(16, 2);
  lcd.print("Security System");
  lcd.setCursor(0, 1);
  lcd.print("Armed & Ready");
  
  // Initialize relay (OFF)
  digitalWrite(RELAY_PIN, LOW);
  
  Serial.println("Smart Security System Initialized");
  Serial.println("System Status: ARMED");
  
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read PIR sensor
  motionDetected = digitalRead(PIR_PIN);
  
  if (motionDetected && systemArmed) {
    // Motion detected - trigger security response
    Serial.println("ALERT: Motion Detected!");
    
    // Display alert on LCD
    lcd.clear();
    lcd.print("MOTION DETECTED!");
    lcd.setCursor(0, 1);
    lcd.print("Security Alert");
    
    // Activate alarm via relay
    digitalWrite(RELAY_PIN, HIGH);
    Serial.println("Alarm Activated");
    
    // Unlock door (servo response)
    doorServo.write(servoUnlockPos);
    Serial.println("Door Unlocked");
    
    // Keep alarm on for 3 seconds
    delay(3000);
    
    // Turn off alarm
    digitalWrite(RELAY_PIN, LOW);
    Serial.println("Alarm Deactivated");
    
    // Lock door again
    doorServo.write(servoLockPos);
    Serial.println("Door Locked");
    
    // Update LCD
    lcd.clear();
    lcd.print("System Reset");
    lcd.setCursor(0, 1);
    lcd.print("Monitoring...");
    
    // Wait before next detection
    delay(5000);
    
  } else {
    // No motion - normal monitoring
    lcd.clear();
    lcd.print("Security System");
    lcd.setCursor(0, 1);
    lcd.print("Monitoring...");
    
    // Ensure door is locked
    doorServo.write(servoLockPos);
  }
  
  delay(1000); // Check every second
}