#define AO_PIN 32  // ESP32's pin GP34 connected to the MQ2 sensor's analog output

const int led_merah = 4;  // Pin for red LED
const int led_hijau = 2;  // Pin for green LED

void setup() {
  // Initialize serial communication
  Serial.begin(9600);

  // Set the ADC attenuation to 11 dB (up to ~3.3V input)
  analogSetAttenuation(ADC_11db);

  Serial.println("Warming up the MQ2 sensor");

  // Initialize LED pins as outputs
  pinMode(led_hijau, OUTPUT);
  pinMode(led_merah, OUTPUT);

  // Wait for the MQ2 sensor to warm up (20 seconds)
  delay(20000); 
}

void loop() {
  // Read the gas value from the MQ2 sensor
  int gasValue = analogRead(AO_PIN);

  // Print the gas value to the Serial Monitor
  Serial.print("MQ2 sensor AB value: ");
  Serial.println(gasValue);

  // Check if the gas value exceeds the threshold
  if (gasValue > 300) {
    digitalWrite(led_hijau, HIGH);  // Turn on the green LED
    digitalWrite(led_merah, LOW);   // Turn off the red LED
    delay(500);  // Delay for half a second

    digitalWrite(led_hijau, LOW);   // Turn off the green LED
    digitalWrite(led_merah, HIGH);  // Turn on the red LED
    delay(500);  // Delay for half a second
  } else {
    digitalWrite(led_hijau, LOW);   // Turn off the green LED
    digitalWrite(led_merah, LOW);   // Turn off the red LED
  }
}