void setup() 

{

  pinMode(10,  OUTPUT);

  pinMode(A5, INPUT);

  Serial.begin(9600);

}

​

void  loop() 

{

  int sensor_read = analogRead(A5);   

  if (sensor_read > 60)

  {

    Serial.print("Gas Sensor Value:");

    Serial.println(sensor_read);

    tone(10,500, 100); //piezo rings 

  }

  else

  {

    noTone(10); //peizo wont ring

  }

  delay(50);

}