材料：
1.DHT11
2.LCD1602
3.LCD1602 转接板
4.Arduino UNO
5.Arduino 传感器扩展版

那个Arduino UNO 我当初挑类个便宜的山寨货买，结果发来和正版的长得一样 O(∩_∩)O吓死我了，，，，

double Fahrenheit(double celsius)

{

        return 1.8 * celsius + 32;

}    //摄氏温度度转化为华氏温度

double Kelvin(double celsius)

{

        return celsius + 273.15;

}     //摄氏温度转化为开氏温度

// 露点（点在此温度时，空气饱和并产生露珠）

// 参考: [url=http://wahiduddin.net/calc/density_algorithms.htm]http://wahiduddin.net/calc/density_algorithms.htm[/url]

double dewPoint(double celsius, double humidity)

{

        double A0= 373.15/(273.15 + celsius);

        double SUM = -7.90298 * (A0-1);

        SUM += 5.02808 * log10(A0);

        SUM += -1.3816e-7 * (pow(10, (11.344*(1-1/A0)))-1) ;

        SUM += 8.1328e-3 * (pow(10,(-3.49149*(A0-1)))-1) ;

        SUM += log10(1013.246);

        double VP = pow(10, SUM-3) * humidity;

        double T = log(VP/0.61078);   // temp var

        return (241.88 * T) / (17.558-T);

}

// 快速计算露点，速度是5倍dewPoint()

// 参考: [url=http://en.wikipedia.org/wiki/Dew_point]http://en.wikipedia.org/wiki/Dew_point[/url]

double dewPointFast(double celsius, double humidity)

{

        double a = 17.271;

        double b = 237.7;

        double temp = (a * celsius) / (b + celsius) + log(humidity/100);

        double Td = (b * temp) / (a - temp);

        return Td;

}

#include <dht11.h>

#include <Wire.h>

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27,16,2); // set the LCD address to 0x27 for a 16 chars and 2 line display

dht11 DHT11;

#define DHT11PIN 2

void setup()

{

  lcd.init();                      // initialize the lcd

  lcd.backlight();

  lcd.print("Waiting...");

  Serial.begin(9600);

}

void loop()

{

  int chk = DHT11.read(DHT11PIN);

  switch (chk)

  {

    case DHTLIB_OK:

                lcd.setCursor(0, 0);

                lcd.print("Temp:");

                lcd.print((float)DHT11.temperature,2);

                lcd.write(0xDF);

                lcd.print("C");

                lcd.setCursor(0, 1);

                lcd.print("Humidity:");

                lcd.print((float)DHT11.humidity,2);

                lcd.print("%");

                break;

    case DHTLIB_ERROR_CHECKSUM:

                lcd.clear();

                lcd.print("Checksum error");

                delay(1000);

                lcd.clear();

                break;

    case DHTLIB_ERROR_TIMEOUT:

                lcd.clear();

                lcd.print("Time out error");

                delay(1000);

                lcd.clear();

                break;

    default:

                lcd.clear();

                lcd.print("Unknown error");

                delay(1000);

                lcd.clear();

                break;

  }

  delay(1000);

}