read a humidity sensor

h.ino

//From the bildr article http://bildr.org/2012/11/hih4030-arduino/

int HIH4030_Pin = A0; //analog pin 0

void setup(){
  Serial.begin(9600);
}

void loop(){

  //To properly caculate relative humidity, we need the temperature.
  float temperature = 25; //replace with a thermometer reading if you have it
  float relativeHumidity  = readSensor();

  Serial.println(relativeHumidity);

  delay(100); //just here to slow it down so you can read it
}


int readSensor(){
  //caculate relative humidity
  float supplyVolt = 5.0;

  // read the value from the sensor:
  int HIH4030_Value = analogRead(HIH4030_Pin);
  //float voltage = HIH4030_Value/1023. * supplyVolt; // convert to voltage value

  // convert the voltage to a relative humidity
  // - the equation is derived from the HIH-4030/31 datasheet
  // - it is not calibrated to your individual sensor
  //  Table 2 of the sheet shows the may deviate from this line
  //float sensorRH = 161.0 * voltage / supplyVolt - 25.8;
  //float trueRH = sensorRH / (1.0546 - 0.0026 * degreesCelsius); //temperature adjustment 

  //return trueRH;
}

s.ino

/******************************************************************************
 * sound_detector_demo.ino
 * Sound detector sample sketch
 * Byron Jacquot @ SparkFun Electronics
 * February 19, 2014
 * https://github.com/sparkfun/Sound_Detector
 * 
 * This sketch demonstrates the use of the Sparkfun Sound Detector board.
 *
 * The Sound Detector is a small board that combines a microphone and some 
 * processing circuitry.  It provides not only an audio output, but also a 
 * binary indication of the presence of sound and an analog representation 
 * of it's amplitude.  
 *
 * This sketch demonstrates two different modes of usage for the Sound
 * Detector.  The gate output (a binary indication that is high when sound
 * is present, and low when conditions are quiet) is used to fire a pin-change 
 * ISR, which lights an LED when the sound is present.  The envelope output 
 * (an analog voltage to rises to indicate the amplitude of the sound) is 
 * sampled in the loop(), and it prints an indication of the level to the 
 * serial terminal. 
 *
 * For more details about the Sound Detector, please check the hookup guide.
 *
 * Connections:
 * The Sound Detector is connected to the Adrduino as follows:
 * (Sound Detector -> Arduino pin)
 * GND → GND
 * VCC → 5V
 * Gate → Pin 2
 * Envelope → A0
 * 
 * Resources:
 * Additional library requirements: none
 * 
 * Development environment specifics:
 * Using Arduino IDe 1.0.5
 * Tested on Redboard, 3.3v/8MHz and 5v/16MHz ProMini hardware.
 * 
 * This code is beerware; if you see me (or any other SparkFun employee) at the
 * local, and you've found our code helpful, please buy us a round!
 * 
 * Distributed as-is; no warranty is given.
 ******************************************************************************/

 // Define hardware connections
#define PIN_GATE_IN 2
#define IRQ_GATE_IN  0
#define PIN_LED_OUT 13
#define PIN_ANALOG_IN A0

// soundISR()
// This function is installed as an interrupt service routine for the pin
// change interrupt.  When digital input 2 changes state, this routine
// is called.
// It queries the state of that pin, and sets the onboard LED to reflect that 
// pin's state.
void soundISR()
{
  int pin_val;

  pin_val = digitalRead(PIN_GATE_IN);
  digitalWrite(PIN_LED_OUT, pin_val);   
}

void setup()
{
  Serial.begin(9600);

  //  Configure LED pin as output
  pinMode(PIN_LED_OUT, OUTPUT);

  // configure input to interrupt
  pinMode(PIN_GATE_IN, INPUT);
  attachInterrupt(IRQ_GATE_IN, soundISR, CHANGE);

  // Display status
  Serial.println("Initialized");
}

void loop()
{
  int value;

  // Check the envelope input
  value = analogRead(PIN_ANALOG_IN);

  // Convert envelope value into a message
  Serial.print("Status: ");
  if(value <= 10)
  {
    Serial.println("Quiet.");
  }
  else if( (value > 10) && ( value <= 30) )
  {
    Serial.println("Moderate.");
  }
  else if(value > 30)
  {
    Serial.println("Loud.");
  }

  // pause for 1 second
  delay(1000);
}