int gas=32;
int led=15;
int threshold=400;
void setup(){
  pinMode(gas,INPUT);
  pinMode(led,OUTPUT); 
  Serial.begin(9600);
}
void loop(){
  int g=analogRead(gas);
  Serial.println(g);
  if(g>threshold){
    Serial.println("harmful gas detected");
    digitalWrite(led,1);

  }
  else{
    Serial.println("No gas detected");
    digitalWrite(led,0);
  }
}