int REDpin=11;int GREENpin=12;int BUZZERpin=10;
int SensorPin =A3; int SensorValue; int total=0;
float average;
void setup() {
  Serial.begin(9600); 
  pinMode(BUZZERpin, OUTPUT); pinMode(REDpin, OUTPUT); pinMode(GREENpin, OUTPUT);

  //Callibration
  Serial.print("\nCallibrating the Sensor");
  //pinMode (SensorPin,INPUT);
  for (int n=1;n<=10;n++){
    total=total+analogRead(SensorPin);
    delay(2000);Serial.print(",");
  }
  average= total/10;
}

void loop() {
  SensorValue=analogRead(SensorPin);

  if (SensorValue<average+10) {
    Serial.println("Normal Mode ");
    digitalWrite(GREENpin, HIGH); delay(1000);
    digitalWrite(GREENpin, LOW); delay(1000);
    digitalWrite(REDpin, LOW);
  }
  else if (SensorValue<average+30){
    Serial.println("Warning Gas Detected");
    int LEDValue = map(SensorValue,average-10,average+100,0,255);
    digitalWrite(REDpin,LEDValue);delay(100);
  }
  else {
    Serial.println("Danger!");
    digitalWrite(BUZZERpin,HIGH);delay(200);
    digitalWrite(BUZZERpin,LOW);delay(200);
  } 
  /*Serial.print("Sensor value is "); Serial.print(SensorValue); Serial.print(", typical Value "); Serial.println(average);
  int LEDValue = map(SensorValue,average-10,average+100,0,255);
  analogWrite(11,LEDValue);
  delay(100);*/

}