/*
  Wokwi | general
  Alexia - Thursday, May 28, 2026 11:56 PM
  Hii, i really need help please https://wokwi.com/projects/465324356872092673
*/

const int LED_PINS[] = {7, 6, 5, 4, 3};
const int BUZZ_PIN = 2;
const int MQ2_PIN = A0;

void setup() {
  int sensorVal = 0;

  Serial.begin(9600);
  for (int i = 0; i < 5; i++) {
    pinMode(LED_PINS[i], OUTPUT);
  }
  pinMode(BUZZ_PIN, OUTPUT);
  while (sensorVal == 0)  {
    sensorVal = analogRead(MQ2_PIN);
    Serial.println("Waiting for sensor to stabilize");
    Serial.println(sensorVal);
    delay(1000);
  }
}

void loop() {
  int sensorMQ2 = map(analogRead(A0), 210, 1010, 0, 100);
  Serial.print("MQ2 sensor value: ");
  Serial.println(sensorMQ2);
  // reset output indicators
  for (int i = 0; i < 5; i++) {
    digitalWrite(LED_PINS[i], LOW);
  }
  noTone(BUZZ_PIN);
  // set output indicators
  if (sensorMQ2 <= 20) {
    digitalWrite(LED_PINS[0], HIGH);
  } else if (sensorMQ2 <= 40) {
    digitalWrite(LED_PINS[1], HIGH);
  }  else if (sensorMQ2 <= 60) {
    digitalWrite(LED_PINS[2], HIGH);
  }  else if (sensorMQ2 <= 80) {
    digitalWrite(LED_PINS[3], HIGH);
  }  else if (sensorMQ2 <= 100) {
    digitalWrite(LED_PINS[4], HIGH);
    tone(BUZZ_PIN, 440, 500);
  }
  delay(1000);
}