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

#define DHTPIN 2             // DHT sensor pin
#define DHTTYPE DHT11        // DHT sensor type
#define LDR_PIN A0           // LDR sensor pin
#define MQ135_PIN A1         // MQ-135 sensor pin
#define BUZZER_PIN 3         // Buzzer pin
#define LED_PIN 4            // LED/headlight pin

LiquidCrystal lcd(5, 6, 7, 8, 9, 10);
DHT dht(DHTPIN, DHTTYPE);

int gasThreshold = 300;      // Gas threshold
float tempThreshold = 40.0;  // Temperature threshold for alert

void setup() {
  dht.begin();
  lcd.begin(16, 2);
  pinMode(BUZZER_PIN, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  lcd.print("Smart Helmet");
  delay(2000);
  lcd.clear();
}

void loop() {
  // Read sensor data
  int ldrValue = analogRead(LDR_PIN);
  int gasValue = analogRead(MQ135_PIN);
  float temp = dht.readTemperature();
  float humidity = dht.readHumidity();

  // Display data on LCD
  lcd.setCursor(0, 0);
  lcd.print("T: " + String(temp) + "C ");
  lcd.print("H: " + String(humidity) + "%");

  lcd.setCursor(0, 1);
  lcd.print("Gas: " + String(gasValue));

  // Light control using LDR
  if (ldrValue < 500) { // Adjust threshold as needed
    digitalWrite(LED_PIN, HIGH);
  } else {
    digitalWrite(LED_PIN, LOW);
  }

  // Gas and temperature alerts
  if (gasValue > gasThreshold || temp > tempThreshold) {
    digitalWrite(BUZZER_PIN, HIGH); // Turn on buzzer
    lcd.setCursor(10, 1);
    lcd.print("ALERT!");
  } else {
    digitalWrite(BUZZER_PIN, LOW); // Turn off buzzer
    lcd.setCursor(10, 1);
    lcd.print("      "); // Clear "ALERT!" message
  }

  delay(1000);
}