Arduino - Slave Node

byte expected_sensor_type_byte = 0x33;
byte expected_hello_byte = 0x32;
byte expected_datarequest_byte = 0x31;

float temperature, humidity, pressure;

void setup() {
  //Initiating serial communication and flushing serial port, just for good measure
  Serial.begin(9600);
  Serial.flush();
  randomSeed(analogRead(A0));

}

void loop() {
  // Check if there is something on the serial port
  if (Serial.available()) {
    //read available data, save to recieved_data
    int recieved_data = Serial.read();

    //Did we recieve the hello byte?
    //This is used by the Raspberry PI to ensure a stable connection
    if (recieved_data == expected_hello_byte) {
      Serial.print("HELLO");
      delay(50);
    }
    //Did we recieve the sensor type byte?
    if (recieved_data == expected_sensor_type_byte) {
      //These lines defines the values to be logged in the csv-file
      //First line is the name of your Arduino Node
      //The following lines are optional, and you can add or remove as many as you want
      //For each Serial.print("name of value") + Serial.print("\t") a column will be generated.
      Serial.print("TempNode");
      Serial.print("\t");
      Serial.print("Temp [C]");
      Serial.print("\t");
      Serial.print("Humidity [%]");
      Serial.print("\t");
      Serial.print("Pressure [kPa]");
      delay(50);
    }
    //Did we recieve the data request byte?
    if (recieved_data == expected_datarequest_byte) {
      //Reading sensor values
      temperature = random(-30, 3000)/100.00;
      humidity = random(3000,9000)/100.00;
      pressure = random(95000, 105000)/100.00;

      //Printing them to the serial port.
      //This has to be the same order as the names from last if.
      Serial.print(temperature);
      Serial.print(";");
      Serial.print(humidity);
      Serial.print(";");
      Serial.print(pressure);
      Serial.print(";");
    }
  }
}