abc

int LED=A1;
const int gas=0;
int MQ2pin=A0;
void setup()
{
  Serial.begin(9600);
  pinMode(9, OUTPUT);
}

void loop()
{
  float sensorvalue,MQ2pin;
  sensorvalue=analogRead(MQ2pin);
  if(sensorvalue>=400)
  {
    digitalWrite(LED,HIGH);
    digitalWrite(9,HIGH);
    Serial.print(sensorvalue);
    Serial.println(“/SMOKE DETECTED”);
  }
  else
  {
    digitalWrite(LED,LOW);
    digitalWrite(9,LOW);
    Serial.println(“Sensor value:”);
    Serial.println(sensorvalue);
  }
  delay(500);
}
float getsensorValue(int pin)
{
  return(analogRead(pin));
}