Abbasi taklif - Hightechrobo bin

void setup() {
  Serial.begin(9600);
  sensors.begin();
  pinMode(heater,OUTPUT);
  pinMode(fan,OUTPUT);
  pinMode(7,OUTPUT);
  pinMode(8,OUTPUT);
  pinMode(9,OUTPUT);
  pinMode(10,OUTPUT);

}
int i = 0;
void loop() {
  if(i == 0){
  int a = random(7,11);
  i = 1;
  }
  int dn = analogRead(ldr);
  sensors.requestTemperatures(); 
  float temp = sensors.getTempCByIndex(0);
    if (temp != DEVICE_DISCONNECTED_C)
  {
  Serial.print("Temperature is: ");
  Serial.println(temp);
    if(temp <= 20){
      digitalWrite(heater, HIGH);
      digitalWrite(fan, LOW);
    }
    if(temp >= 28){
      digitalWrite(heater, LOW);
      digitalWrite(fan, HIGH);
    }
    if(temp < 28 && temp > 20){
      digitalWrite(heater, LOW);
      digitalWrite(fan, LOW);
    }
    if(dn < 400){
      digitalWrite(a,HIGH);
      i =1;
    }
    if(dn >= 400){
      i =0;
      digitalWrite(7,LOW);
      digitalWrite(8,LOW);
      digitalWrite(9,LOW);
      digitalWrite(10,LOW);
    }
  }
  else
  {
    Serial.println("Error to reading data");
  }

}