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

// LCD: RS, E, D4, D5, D6, D7
LiquidCrystal lcd(7, 6, 5, 4, 3, 2);
Servo doorServo;

const int trigPin = 8;
const int echoPin = 9;
const int servoPin = 10;

long duration;
int distance;

void setup() {
  lcd.begin(16, 2);
  lcd.print("Auto Door System");
  delay(2000);
  lcd.clear();

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  doorServo.attach(servoPin);
  doorServo.write(0); // Door closed
}

void loop() {
  // Trigger the ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Measure echo pulse duration
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm ");

  if (distance < 20) {
    lcd.setCursor(0, 1);
    lcd.print("Person Detected  ");
    doorServo.write(90); // Open door
    delay(2000);
    lcd.setCursor(0, 1);
    lcd.print("Door Opened      ");
    delay(2000);
  } else {
    lcd.setCursor(0, 1);
    lcd.print("No One Nearby    ");
    doorServo.write(0); // Close door
  }

  delay(500);
}