// where is the humidity sensor connected to?
int humPin = 0;

void setup()
{
  // initialise the serial output
  Serial.begin(115200);
}

void loop()
{
  // fix temperature (if you can get it from a temperatur sensor, please do so!)
  double temperatureC = 20;
  
  // read the value from the pin
  int humReading = analogRead(humPin); 
  // convert it into voltage (Vcc = 5V)
  double volt = humReading / 1023.0 * 5;
  // calculate the sensor humitidy
  double sensorRH = 161.*volt/5 - 25.8;
  // adapt this for the given temperature
  double trueRH = sensorRH / (1.0546 - 0.0026*temperatureC);  
 
  // print it to the serial output
  Serial.println(trueRH);
  
  // wait a second
  delay(1000);            
}