#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#include <ESP32Servo.h>

// I2C address of LCD
#define LCD_I2C_ADDRESS 0x27

// Ultrasonic sensor pins
#define TRIG_PIN 4
#define ECHO_PIN 2

// Buzzer pin
#define BUZZER_PIN 15

// DHT22 sensor pin
#define DHT_PIN 18

// Servo motor pin
#define SERVO_PIN 27

// LCD object
LiquidCrystal_I2C lcd(LCD_I2C_ADDRESS, 16, 2);

// DHT object
DHT dht(DHT_PIN, DHT22);

// Servo object
Servo servoMotor;

void setup() {
  // Initialize LCD
  lcd.init();
  lcd.backlight();

  // Set trigger pin as output
  pinMode(TRIG_PIN, OUTPUT);

  // Set echo pin as input
  pinMode(ECHO_PIN, INPUT);

  // Set buzzer pin as output
  pinMode(BUZZER_PIN, OUTPUT);

  // Attach the servo object to the servo pin
  servoMotor.attach(SERVO_PIN);

  // Initialize DHT sensor
  dht.begin();
}

void loop() {
  // Generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Measure duration of pulse from ECHO pin
  float duration_us = pulseIn(ECHO_PIN, HIGH);

  // Calculate the distance
  float distance_cm = 0.017 * duration_us;

  // Read temperature and humidity from DHT22
  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Clear LCD
  lcd.clear();

  // Print distance on the first line of LCD
  lcd.setCursor(0, 0);
  lcd.print("Distance:");
  lcd.print(distance_cm);
  lcd.print("cm");

  // Print temperature and humidity on the second line of LCD with decimal format
  lcd.setCursor(0, 1);
  lcd.print("T:");
  lcd.print(temperature, 1); // Display temperature with 1 decimal place
  lcd.print((char)223);
  lcd.print("C | H:");
  lcd.print(humidity, 0); // Display humidity with 1 decimal place
  lcd.print("%"); // Use "P" instead of "%"

  // If the distance is less than a threshold, activate the buzzer and move the servo
  if (distance_cm < 10) {
    digitalWrite(BUZZER_PIN, HIGH); // Turn on the buzzer
    servoMotor.write(90);  // Rotate the servo to 90 degrees
  } else {
    digitalWrite(BUZZER_PIN, LOW); // Turn off the buzzer
    servoMotor.write(0);   // Rotate the servo to 0 degrees
  }

  // Delay for 200ms
  delay(200);
}