---

int smokeSensor = A0;
int fanPin = 7;
int buzzerPin = 8;
int ledPin = 9;

void setup() {
  pinMode(fanPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  int smokeLevel = analogRead(smokeSensor);

  if (smokeLevel > 300) {
    digitalWrite(fanPin, HIGH);
    digitalWrite(buzzerPin, HIGH);
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(fanPin, LOW);
    digitalWrite(buzzerPin, LOW);
    digitalWrite(ledPin, LOW);
  }

  delay(500);
}