DH11数字温湿度传感器是一种集温度、湿度一体的复合传感器，它能把温度和湿度物理量通过温、湿度敏感元件和相应电路转化成方便计算机、PLC、智能仪表等数据采集设备直接读取的数字量。DHT11由电阻式感湿器件和NTC系数感温器件构成，具有校准数字信号输出功能，采用单总线串行接口，输出数据一共5个字节，分别表示：湿度整数位、湿度小数位，温度整数位、温度小数位及校验和，其中检验和为湿度与温度之和的最低八位数据。
|
arduino引脚 |
模块引脚 |
|
D2 |
S |
|
5V |
VCC |
|
GND |
GND |
double Fahrenheit(double celsius)
{
return 1.8 * celsius + ;
} //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-);
SUM += 5.02808 * log10(A0);
SUM += -1.3816e-7 * (pow(, (11.344*(-/A0)))-) ;
SUM += 8.1328e-3 * (pow(,(-3.49149*(A0-)))-) ;
SUM += log10(1013.246);
double VP = pow(, SUM-) * 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/);
double Td = (b * temp) / (a - temp);
return Td;
} #include <dht11.h> dht11 DHT11; #define DHT11PIN 2 void setup()
{
Serial.begin();
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, ); Serial.print("Temperature (oC): ");
Serial.println((float)DHT11.temperature, ); Serial.print("Temperature (oF): ");
Serial.println(Fahrenheit(DHT11.temperature), ); Serial.print("Temperature (K): ");
Serial.println(Kelvin(DHT11.temperature), ); 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();
}