/*?DHT?library?

MIT?license*/

#include?“DHT.h“

DHT::DHT（uint8_t?pin?uint8_t?type?uint8_t?count）?{
??_pin?=?pin;
??_type?=?type;
??_count?=?count;
??firstreading?=?true;
}

void?DHT::begin（void）?{
??//?set?up?the?pins!
??pinMode（_pin?INPUT）;
??digitalWrite（_pin?HIGH）;
??_lastreadtime?=?0;
}

//boolean?S?==?Scale.??True?==?Farenheit;?False?==?Celcius
float?DHT::readTemperature（bool?S）?{
??float?f;

??if?（read（））?{
????switch?（_type）?{
????case?DHT11:
??????f?=?data[2];
??????if（S）
??????	f?=?convertCtoF（f）;
??????	
??????return?f;
????case?DHT22:
????case?DHT21:
??????f?=?data[2]?&?0x7F;
??????f?*=?256;
??????f?+=?data[3];
??????f?/=?10;
??????if?（data[2]?&?0x80）
	f?*=?-1;
??????if（S）
	f?=?convertCtoF（f）;

??????return?f;
????}
??}
??return?NAN;
}

float?DHT::convertCtoF（float?c）?{
	return?c?*?9?/?5?+?32;
}

float?DHT::convertFtoC（float?f）?{
??return?（f?-?32）?*?5?/?9;?
}

float?DHT::readHumidity（void）?{
??float?f;
??if?（read（））?{
????switch?（_type）?{
????case?DHT11:
??????f?=?data[0];
??????return?f;
????case?DHT22:
????case?DHT21:
??????f?=?data[0];
??????f?*=?256;
??????f?+=?data[1];
??????f?/=?10;
??????return?f;
????}
??}
??return?NAN;
}

float?DHT::computeHeatIndex（float?tempFahrenheit?float?percentHumidity）?{
??//?Adapted?from?equation?at:?https://github.com/adafruit/DHT-sensor-library/issues/9?and
??//?Wikipedia:?http://en.wikipedia.org/wiki/Heat_index
??return?-42.379?+?
???????????2.04901523?*?tempFahrenheit?+?
??????????10.14333127?*?percentHumidity?+
??????????-0.22475541?*?tempFahrenheit*percentHumidity?+
??????????-0.00683783?*?pow（tempFahrenheit?2）?+
??????????-0.05481717?*?pow（percentHumidity?2）?+?
???????????0.00122874?*?pow（tempFahrenheit?2）?*?percentHumidity?+?
???????????0.00085282?*?tempFahrenheit*pow（percentHumidity?2）?+
??????????-0.00000199?*?pow（tempFahrenheit?2）?*?pow（percentHumidity?2）;
}


boolean?DHT::read（void）?{
??uint8_t?laststate?=?HIGH;
??uint8_t?counter?=?0;
??uint8_t?j?=?0?i;
??unsigned?long?currenttime;

??//?Check?if?sensor?was?read?less?than?two?seconds?ago?and?return?early
??//?to?use?last?reading.
??currenttime?=?millis（）;
??if?（currenttime?????//?ie?there?was?a?rollover
????_lastreadtime?=?0;
??}
??if?（!firstreading?&&?（（currenttime?-?_lastreadtime）?????return?true;?//?return?last?correct?measurement
????//delay（2000?-?（currenttime?-?_lastreadtime））;
??}
??firstreading?=?false;
??/*
????Serial.print（“Currtime:?“）;?Serial.print（currenttime）;
????Serial.print（“?Lasttime:?“）;?Serial.print（_lastreadtime）;
??*/
??_lastreadtime?=?millis（）;

??data[0]?=?data[1]?=?data[2]?=?data[3]?=?data[4]?=?0;
??
??//?pull?the?pin?high?and?wait?250?milliseconds
??digitalWrite（_pin?HIGH）;
??delay（250）;

??//?now?pull?it?low?for?~20?milliseconds
??pinMode（_pin?OUTPUT）;
??digitalWrite（_pin?LOW）;
??delay（20）;
??noInterrupts（）;
??digitalWrite（_pin?HIGH）;
??delayMicroseconds（40）;
??pinMode（_pin?INPUT）;

??//?read?in?timings
??for?（?i=0;?i????counter?=?0;
????while?（

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\
?????文件?????????177??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\.gitignore
?????文件????????3980??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\DHT.cpp
?????文件?????????735??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\DHT.h
?????目錄???????????0??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\DHTtester\
?????文件????????2262??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\DHTtester\DHTtester.ino
?????文件???????18026??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\LICENSE
?????文件?????????138??2014-08-05?15:12??temperature-and-humidity-sensor-AM2301-master\README.md