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

LiquidCrystal lcd(12, 11, 5, 4, 3, 2); // Pins attached to LCD screen

Servo doorServo; // Servo motor object

const int motionSensorPin = A0; // Analog pin attached to motion sensor
int motionSensorState = 0; // Variable for motion sensor
int doorState = 0; // Variable for servo motor
unsigned long doorOpenTime;
unsigned long lastMotion;
const unsigned long doorOpenPeriod = 2000; // Indicates time the door is open

void setup() {
  doorServo.attach(9); // Pin attached to servo motor
  doorServo.write(0); // Initial position for servo motor
  lcd.begin(16, 2); 
  lcd.print("The door is");
  lcd.setCursor(0, 1); // Setting next message on next row
  lcd.print("closed"); // Indicates initial position of "door"
}

void loop() {
  motionSensorState = analogRead(motionSensorPin); // Read the motion sensor value
  
  // Check if motion is detected
  if (motionSensorState > 500) {
    lastMotion = millis(); // Starts counting from the last detected motion
    if (doorState == 0) {
      doorOpenTime = millis();
      doorServo.write(90); // Open the door
      lcd.clear();
      lcd.print("The door is");
      lcd.setCursor(0, 1); // Setting next message on next row
      lcd.print("open"); // Open door message
      delay(10);
      doorState = 1; // Update state of servo
    }
  } else {
    if (doorOpenTime - lastMotion >= doorOpenPeriod && doorState == 1) {
      doorServo.write(0); // Close the door
      doorState = 0; // Update state of servo
      lcd.clear();
      lcd.print("The door is");
      lcd.setCursor(0, 1); // Setting next message on next row
      lcd.print("closed"); // Closed door message
      }
    }
  }