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

// Pin Definitions
#define DHTPIN 2
#define DHTTYPE DHT11
#define MQ135PIN A0
#define LDRPIN A1
#define LEDPIN 5
#define BUZZERPIN 4

// Initialize DHT sensor
DHT dht(DHTPIN, DHTTYPE);

// Initialize LCD
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  // Begin serial communication
  Serial.begin(9600);
  
  // Initialize sensors and peripherals
  dht.begin();
  lcd.begin(16,2);
  lcd.backlight();
  
  pinMode(MQ135PIN, INPUT);
  pinMode(LDRPIN, INPUT);
  pinMode(LEDPIN, OUTPUT);
  pinMode(BUZZERPIN, OUTPUT);

  // Display startup message
  lcd.setCursor(0, 0);
  lcd.print("Smart Helmet");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read temperature and humidity
  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  // Read gas level
  int gasLevel = analogRead(MQ135PIN);

  // Read light intensity
  int lightLevel = analogRead(LDRPIN);

  // Display data on LCD
  lcd.setCursor(0, 0);
  lcd.print("T:");
  lcd.print(temp);
  lcd.print(" H:");
  lcd.print(hum);

  lcd.setCursor(0, 1);
  lcd.print("Gas:");
  lcd.print(gasLevel);

  // Alert for high gas level
  if (gasLevel > 600) { // Adjust threshold as needed
    digitalWrite(BUZZERPIN, HIGH);
  } else {
    digitalWrite(BUZZERPIN, LOW);
  }

  // Automated light control
  if (lightLevel < 500) { // Adjust threshold for low light
    digitalWrite(LEDPIN, HIGH); // Turn on LED
  } else {
    digitalWrite(LEDPIN, LOW); // Turn off LED
  }

  delay(1000); // Update interval
}