基于Arduino的温湿度实时显示实验（I2C12864显示屏、DHT11）

#include <RSCG12864B.h>//引用库文件
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: http://wahiduddin.net/calc/density_algorithms.htm
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: http://en.wikipedia.org/wiki/Dew_point
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>//程序中调用了dht11的库

dht11 DHT11;//定义一个名字叫做DHT11，类型为dht11的值。

#define DHT11PIN 2//定义DHT11的引脚号为D2。
void setup()
{
Serial.begin(9600);//设置串口波特率9600
RSCG12864B.begin();//串口初始化
    RSCG12864B.brightness(255);//屏幕亮度
Serial.println("DHT11 TEST PROGRAM ");
Serial.print("LIBRARY VERSION: ");
Serial.println(DHT11LIB_VERSION);
Serial.println();
}
void loop()
{
Serial.println("\n");

int chk = DHT11.read(DHT11PIN);

Serial.print("Read sensor: ");
switch (chk)
{
case DHTLIB_OK:
Serial.println("OK");
break;
case DHTLIB_ERROR_CHECKSUM:
Serial.println("Checksum error");
break;
case DHTLIB_ERROR_TIMEOUT:
Serial.println("Time out error");
break;
default:
Serial.println("Unknown error");
break;
}

Serial.print("Humidity (%): ");
Serial.println((float)DHT11.humidity, 2);

Serial.print("Temperature (oC): ");
Serial.println((float)DHT11.temperature, 2);

Serial.print("Temperature (oF): ");
Serial.println(Fahrenheit(DHT11.temperature), 2);

Serial.print("Temperature (K): ");
Serial.println(Kelvin(DHT11.temperature), 2);

Serial.print("Dew Point (oC): ");
Serial.println(dewPoint(DHT11.temperature, DHT11.humidity));

Serial.print("Dew PointFast (oC): ");
Serial.println(dewPointFast(DHT11.temperature, DHT11.humidity));

delay(2000);
unsigned char i;
    char chn[]={  0xCE, 0xC2,0xB6, 0xC8,0xA3, 0xBA,0,};//温度
    char zay[]={  0xCA, 0xAA,0xB6, 0xC8,0xA3, 0xBA,0,};//湿度

    RSCG12864B.clear();//屏幕清屏
    RSCG12864B.print_string_16_xy(0,0,chn);//坐标0,0，显示chn里的内容
    RSCG12864B.print_string_16_xy(0,20,zay);//坐标0,20，显示zay里的内容
   char text[5];
   {
     dtostrf(DHT11.temperature,5,2,text);//dtostrf函数很好用，可以将字符变成字符串显示。
    RSCG12864B.print_string_12_xy(40,5,text);//定义字符串坐标。
     }
char work[5];
     dtostrf(DHT11.humidity,5,2,work);//dtostrf函数很好用，可以将字符变成字符串显示。
     RSCG12864B.print_string_12_xy(40,25,work);//定义字符串坐标。

}