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

const char* ssid = "Wokwi-GUEST ";
const char* password = "";
const char* token = "YOUR TOKEN";

// Define pins for MQ135, LEDs, and buzzer
#define MQ135_PIN 34        // Analog pin for MQ135 sensor
#define STATUS_LED_PIN 13   // Status LED
#define ALERT_LED_PIN 12    // Alert LED
#define BUZZER_PIN 14       // Buzzer

// Initialize the LCD with I2C address 0x27
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Threshold for MQ135 gas concentration level to trigger alert
const int gasThreshold = 500;
const int sensorThres = 100;

void setup() {
  // Begin Serial communication
  Serial.begin(115200);

  // Initialize LCD
  lcd.init();
  lcd.backlight();
  lcd.print("Air Quality:");

  // Set up LED and buzzer pins as outputs
  pinMode(STATUS_LED_PIN, OUTPUT);
  pinMode(ALERT_LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  // Turn on Status LED to show the system is active
  digitalWrite(STATUS_LED_PIN, HIGH);

  // Short delay for system initialization
  delay(1000);
}

void loop() {
  // Read MQ135 sensor value
  int mq135Value = analogRead(MQ135_PIN);
  Serial.print("MQ135 Reading: ");
  Serial.println(mq135Value);

  // Display the reading on the LCD
  lcd.setCursor(0, 1);  // Move to the second row
  lcd.print("Reading: ");
  lcd.print(mq135Value);
  lcd.print("    "); // Clear extra characters

  // Check if gas level exceeds the threshold
  if (mq135Value > gasThreshold) {
    digitalWrite(ALERT_LED_PIN, HIGH);  // Turn on Alert LED
    digitalWrite(BUZZER_PIN, HIGH);     // Turn on buzzer
  } else {
    digitalWrite(ALERT_LED_PIN, LOW);   // Turn off Alert LED
    digitalWrite(BUZZER_PIN, LOW);      // Turn off buzzer
  }

  delay(1000);  // 1 second delay before next reading
}