#include <Servo.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

Servo gate;

const int trigPin = 7;
const int echoPin = 6;
const int servoPin = 9;
const int relayPin = 8;

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(relayPin, OUTPUT);
  
  gate.attach(servoPin);
  gate.write(0);  // Initial closed gate
  
  lcd.init();
  lcd.backlight();
  
  Serial.begin(9600);
}

void loop() {
  // Ultrasonic distance calculation
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

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

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  if (distance < 15) {  
    gate.write(90);            
    digitalWrite(relayPin, HIGH);
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Car Detected");
    lcd.setCursor(0, 1);
    lcd.print("Gate Open");
  } else {
    gate.write(0);             
    digitalWrite(relayPin, LOW);  
    
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("No Car");
    lcd.setCursor(0, 1);
    lcd.print("Gate Closed");
  }
  delay(500);
}