int buzzer = 7;
  int smokeA0 = A0;
  int sensorThres=440 ;

  int ledPin = 9;
  int ldrPin = A5;
  int thershold1 =150;
  int thershold2 = 100;


  int PIRsensor = 11;
  int state = LOW;
  int val = 0;




  void setup (){

  pinMode (buzzer, OUTPUT) ;
  pinMode (smokeA0, INPUT) ;

  pinMode(ledPin, OUTPUT);
  pinMode(ldrPin, INPUT);

  pinMode(PIRsensor, INPUT);

  Serial.begin (9600) ;
  }

  void loop (){
  int analogSensor = analogRead (smokeA0) ;
  Serial.print ("Gas value:");
  Serial.println (analogSensor) ;

  int ldrStatus = analogRead(ldrPin);

   Serial.print ("LDR value:");
   Serial.println(ldrStatus);

  val = digitalRead(PIRsensor);
  Serial.print ("Motion value:");
  Serial.println(val);


  if (analogSensor > sensorThres)
  {
  digitalWrite (buzzer, HIGH);
  }

  else if (ldrStatus < thershold2) {

  analogWrite(ledPin, 255);

  Serial.println(ldrStatus);

  } else if(ldrStatus < thershold1) {

  analogWrite(ledPin, 55);

  Serial.println(ldrStatus);

  }




   else if (val == HIGH) {
      digitalWrite(ledPin, HIGH);
      delay(500);

      if (state == LOW) {
        Serial.println("Motion detected!");
        state = HIGH;
      }
    }

    else {
        digitalWrite(ledPin, LOW);
        delay(500);

        if (state == HIGH){
          Serial.println("Motion stopped!");
          state = LOW;
      }



  digitalWrite (buzzer, LOW) ;
   digitalWrite(ledPin, LOW);



  }

  delay(100);
  }