#include <LiquidCrystal.h>
#include "DHT.h"

// Define pins for the LCD
const int rs = 23, en = 22, d4 = 21, d5 = 19, d6 = 18, d7 = 5;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

// Define DHT sensor
#define DHTPIN 15       // Pin connected to the DHT22
#define DHTTYPE DHT22   // DHT 22 (AM2302)
DHT dht(DHTPIN, DHTTYPE);

// Define LDR pins
const int ldrAnalogPin = 34; // LDR analog pin (A0)
const int ldrDigitalPin = 26; // LDR digital pin (D0)

// Define other sensors' pins if needed (example for MQ-135, change pins accordingly)
const int mq135Pin = 36; // Example pin for MQ-135

void setup() {
  // Initialize the LCD
  lcd.begin(16, 2);
  
  // Initialize the DHT sensor
  dht.begin();
  
  // Set up the LDR digital pin
  pinMode(ldrDigitalPin, INPUT);
  
  // Set up MQ-135 analog pin
  pinMode(mq135Pin, INPUT);
  
  // Print an initial message to the LCD
  lcd.print("Initializing...");
  delay(2000);
}

void loop() {
  // Read temperature and humidity from DHT22
  float humidity = dht.readHumidity();
  float temperature = dht.readTemperature();
  
  // Read LDR values
  int ldrAnalogValue = analogRead(ldrAnalogPin);
  int ldrDigitalValue = digitalRead(ldrDigitalPin);
  
  // Example reading from MQ-135 (replace with actual logic if needed)
  int mq135Value = analogRead(mq135Pin);
  
  // Clear the LCD for fresh output
  lcd.clear();
  
  // Display temperature and humidity
  lcd.setCursor(0, 0);
  lcd.print("Temp: ");
  lcd.print(temperature);
  lcd.print(" C");

  lcd.setCursor(0, 1);
  lcd.print("Humidity: ");
  lcd.print(humidity);
  lcd.print(" %");

  // Display LDR analog value
  lcd.setCursor(0, 0);
  lcd.print("LDR: ");
  lcd.print(ldrAnalogValue);

  // Check if light threshold is crossed based on LDR digital pin
  if (ldrDigitalValue == HIGH) {
    lcd.setCursor(0, 1);
    lcd.print("Light detected");
  } else {
    lcd.setCursor(0, 1);
    lcd.print("Low light");
  }

  // If using MQ-135, display the value as well
  lcd.setCursor(0, 0);
  lcd.print("MQ-135: ");
  lcd.print(mq135Value);
  
  // Delay before next reading
  delay(2000);
}