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

#define trigPin 9
#define echoPin 8
#define buzzerPin 10
#define ledAlertPin 11
#define ledClearPin 12

// Initialize the LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);  // Address 0x27, 16 chars, 2 rows

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledAlertPin, OUTPUT);
  pinMode(ledClearPin, OUTPUT);
  Serial.begin(9600);
  
  // Initialize the LCD
  lcd.init();
  lcd.backlight();  // Turn on the backlight
  lcd.setCursor(0, 0);
  lcd.print("Parking System");
  delay(2000);  // Display the message for 2 seconds
  lcd.clear();
}

void loop() {
  // Clear the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);

  // Set the trigPin high for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read the echoPin and calculate the distance
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  // Display the distance on the LCD
  lcd.setCursor(0, 0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm   ");  // Clear remaining characters

  // If the distance is less than 100 cm, activate the continuous beep and alert LED
  if (distance < 300 && distance > 0) { // Adjust if necessary
    tone(buzzerPin, 1000);  // Produce continuous beep at 1000 Hz
    digitalWrite(ledAlertPin, HIGH);
    digitalWrite(ledClearPin, LOW);
    
    // Display alert message on the LCD
    lcd.setCursor(0, 1);  // Move to second row
    lcd.print("Vehicle Detected");
  } else {
    // Otherwise, stop the beep and show clear status
    noTone(buzzerPin);  // Stop the beep
    digitalWrite(ledAlertPin, LOW);
    digitalWrite(ledClearPin, HIGH);
    
    // Display clear road message on the LCD
    lcd.setCursor(0, 1);
    lcd.print("Road is Clear   ");  // Clear remaining characters
  }

  delay(500);  // Delay for half a second
}