void setup() {
  // put your setup code here, to run once:
pinMode(A1, INPUT);
pinMode(7, OUTPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
int gas_level=analogRead(A1);
Serial.println(gas_level);
if(gas_level>400){
digitalWrite(7, HIGH);
}
else{
  digitalWrite(7, LOW);
}
delay(1000);
}
// MQ2 SENSOR - USED TO DETECT CO2 OR O2 GAS LEAKAGE