DHT library
Fork of DHT by
Revision 1:6d97d5338f91, committed 2016-08-21
- Comitter:
- SomeRandomBloke
- Date:
- Sun Aug 21 17:48:16 2016 +0000
- Parent:
- 0:9b5b3200688f
- Commit message:
- First
Changed in this revision
DHT.cpp | Show annotated file Show diff for this revision Revisions of this file |
--- a/DHT.cpp Mon Jul 09 19:47:43 2012 +0000 +++ b/DHT.cpp Sun Aug 21 17:48:16 2016 +0000 @@ -32,7 +32,9 @@ #include "DHT.h" -#define DHT_DATA_BIT_COUNT 41 +//extern Serial pc; +// was 41 +#define DHT_DATA_BIT_COUNT 40 DHT::DHT(PinName pin,int DHTtype) { _pin = pin; @@ -134,12 +136,19 @@ DHT_data[i]=b; } - if (DHT_data[4] == ((DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3]) & 0xFF)) { + if (DHT_data[4] == ((DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3]) & 0xFF) || + DHT_data[4] == ((DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3]-1) & 0xFF)) { _lastReadTime = currentTime; _lastTemperature=CalcTemperature(); _lastHumidity=CalcHumidity(); } else { +/*for( int i=0; i < 5; i++ ) { + pc.printf("%02X ",DHT_data[i]); + } + pc.printf("\n"); + pc.printf("%04X\n",(DHT_data[0] + DHT_data[1] + DHT_data[2] + DHT_data[3])); +*/ err = ERROR_CHECKSUM; } @@ -148,12 +157,12 @@ } float DHT::CalcTemperature() { - int v; + float v; switch (_DHTtype) { case DHT11: v = DHT_data[2]; - return float(v); + return v; case DHT22: v = DHT_data[2] & 0x7F; v *= 256; @@ -161,7 +170,7 @@ v /= 10; if (DHT_data[2] & 0x80) v *= -1; - return float(v); + return v; } return 0; } @@ -171,25 +180,25 @@ } float DHT::ConvertCelciustoFarenheit(float celsius) { - return celsius * 9 / 5 + 32; + return celsius * 9 / 5 + 32.0f; } float DHT::ConvertCelciustoKelvin(float celsius) { - return celsius + 273.15; + return celsius + 273.15f; } // dewPoint function NOAA // reference: http://wahiduddin.net/calc/density_algorithms.htm float DHT::CalcdewPoint(float celsius, float humidity) { - float A0= 373.15/(273.15 + celsius); - float 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) ; + float A0= 373.15f/(273.15f + celsius); + float SUM = -7.90298f * (A0-1); + SUM += 5.02808f * log10(A0); + SUM += -1.3816e-7 * (pow(10, (11.344f*(1-1/A0)))-1) ; + SUM += 8.1328e-3f * (pow(10,(-3.49149f*(A0-1.0f)))-1) ; SUM += log10(1013.246); float VP = pow(10, SUM-3) * humidity; - float T = log(VP/0.61078); // temp var - return (241.88 * T) / (17.558-T); + float T = log(VP/0.61078f); // temp var + return (241.88f * T) / (17.558f-T); } // delta max = 0.6544 wrt dewPoint() @@ -214,18 +223,18 @@ } float DHT::CalcHumidity() { - int v; + float v; switch (_DHTtype) { case DHT11: v = DHT_data[0]; - return float(v); + return v; case DHT22: v = DHT_data[0]; v *= 256; v += DHT_data[1]; v /= 10; - return float(v); + return v; } return 0; }