// ESP32 + MQ135 Custom Chip (multi-gas version)
// IN  -> GPIO34 (ADC input)
// OUT -> GPIO25 (digital input)

const int PIN_IN  = 34;  // ADC
const int PIN_OUT = 25;  // digital

void setup() {
  Serial.begin(115200);
  pinMode(PIN_OUT, INPUT);
}

void loop() {
  // baca analog (0..4095)
  int raw = analogRead(PIN_IN);
  float voltage = (raw / 4095.0f) * 5.0f;

  // konversi ke ppm_total (model di chip: 0-5V -> 0-5000 ppm)
  float ppm_total = (voltage / 5.0f) * 5000.0f;

  // baca digital output
  int outVal = digitalRead(PIN_OUT);

  Serial.print("ADC=");
  Serial.print(raw);
  Serial.print("  V=");
  Serial.print(voltage, 3);
  Serial.print(" V  Total PPM≈");
  Serial.print(ppm_total, 1);
  Serial.print("  OUT=");
  Serial.println(outVal ? "HIGH (>= threshold)" : "LOW (< threshold)");

  delay(500);
}