#include <WiFi.h>
#include "ThingSpeak.h"
#include <LiquidCrystal_I2C.h>

#define WIFI_SSID "Wokwi-GUEST"      // ganti dengan nama jaringan WiFi kamu
#define WIFI_PASSWORD ""             // ganti dengan kata sandi WiFi kamu

#define SECRET_CH_ID 2331756         // ganti dengan nomor channel kamu
#define SECRET_WRITE_APIKEY "QOCITVGF62V1BB7I"   // ganti dengan API Key write channel kamu

#define MQ2 34   // pin analog MQ2
#define LED 14   // pin LED
#define BUZZER_PIN 4   // pin Buzzer

WiFiClient client;
unsigned long myChannelNumber = SECRET_CH_ID;
const char *myWriteAPIKey = SECRET_WRITE_APIKEY;

int gas;
unsigned long dataMillis = 0;

LiquidCrystal_I2C lcd(0x27, 16, 2);  // Inisialisasi LCD (0x27 adalah alamat I2C)

void setup() {
  Serial.begin(115200);  // Inisialisasi serial

  pinMode(MQ2, INPUT);
  pinMode(LED, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);

  digitalWrite(LED, LOW);
  digitalWrite(BUZZER_PIN, LOW);

  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.print("Connecting to Wi-Fi");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print(".");
    delay(300);
  }
  Serial.println();
  Serial.print("Connected with IP: ");
  Serial.println(WiFi.localIP());
  Serial.println();

  ThingSpeak.begin(client);  // Inisialisasi ThingSpeak

  lcd.init();  // Inisialisasi LCD
  lcd.backlight();   // Hidupkan backlight
  lcd.setCursor(0, 0);
  lcd.print("Gas: ");
}

void loop() {
  gas = analogRead(MQ2);

  Serial.printf("Gas: %d\n", gas);

  ThingSpeak.setField(3, gas);

  if (millis() - dataMillis > 20000) {
    int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
    if (x == 200) {
      Serial.println("Channel update successful.");
    } else {
      Serial.println("Problem updating channel. HTTP error code " + String(x));
    }
    dataMillis = millis();
  }

  if (gas > 500) {
    digitalWrite(LED, HIGH);
    tone(BUZZER_PIN, 1000); // Aktifkan buzzer dengan frekuensi 1000Hz
    lcd.setCursor(5, 1);
    lcd.print("Gas detected!");
  } else {
    digitalWrite(LED, LOW);
    noTone(BUZZER_PIN); // Pastikan buzzer mati
    lcd.setCursor(5, 1);
    lcd.print("              "); // Hapus pesan sebelumnya
  }

  lcd.setCursor(5, 0);  // Posisi kursor di baris 0, kolom 5
  lcd.print("     ");   // Hapus nilai sebelumnya
  lcd.setCursor(5, 0);
  lcd.print(gas);

  delay(2000);  // Tampilkan setiap 2 detik sekali
}