SHT75 Sensirion Humidity and Temperature Sensors - Help!

i buy this sensor and i try to connect with Arduino Uno, i have problems with library :

http://playground.arduino.cc/Code/Sensirion

error is: #Include “WConstants.h”:

the next step i try this library :

With this example work the sensor but with out Draw Point and Wet Bulb

also i found in the google this model Mastech MS6508 this tool work with SHT75 sensor and this read Wet Bulb. .

Can i read wet bulb and Draw point in Arduino with SHT 75?

The original code is

/**
 * ReadSHT1xValues
 *
 * Read temperature and humidity values from an SHT1x-series (SHT10,
 * SHT11, SHT15) sensor.
 *
 * Copyright 2009 Jonathan Oxer <jon@oxer.com.au>
 * www.practicalarduino.com
 */

#include <SHT1x.h>

// Specify data and clock connections and instantiate SHT1x object
#define dataPin  10
#define clockPin 11
SHT1x sht1x(dataPin, clockPin);

void setup()
{
   Serial.begin(9600); // Open serial connection to report values to host
   Serial.println("Starting up");
}

void loop()
{
  float temp_c;
  float temp_f;
  float humidity;

  // Read values from the sensor
  temp_c = sht1x.readTemperatureC();
  temp_f = sht1x.readTemperatureF();
  humidity = sht1x.readHumidity();

  // Print the values to the serial port
  Serial.print("Temperature: ");
  Serial.print(temp_c, DEC);
  Serial.print("C / ");
  Serial.print(temp_f, DEC);
  Serial.print("F. Humidity: ");
  Serial.print(humidity);
  Serial.println("%");

  delay(2000);
}/code]

if you know the temperature, I think you get that from the SHT15 and you know the humidity, you get that from the SHT15 you can calculate wet bulb. depending on the size of your temperature range, you can either do it with math, or use a look-up table. then once you have wet bulb and your dry bulb, you can calculate for dew point

please note that if you are trying to find dew point, then you should ask how to find dew point. asking to find wet bulb so you can calculate dew point is only a stop on the way.