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### Topic: Help with DHT11 (Read 15349 times)previous topic - next topic

#### robtillaart

#15
##### Mar 17, 2012, 09:50 pm

- http://arduino.cc/playground/Main/DHTLib -

is 1.0 compatible but I have to update

- http://arduino.cc/playground/Main/DHT11Lib -

going to fix it now ...
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

#### robtillaart

#16
##### Mar 17, 2012, 10:10 pm
done.
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

#### Duckie58

#17
##### Mar 17, 2012, 11:01 pm
If you are looking for dew point and conversions, I use this code:
Code: [Select]
`// dewPoint function NOAA// reference: 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);}// delta max = 0.6544 wrt dewPoint()// 5x faster than dewPoint()// reference: http://en.wikipedia.org/wiki/Dew_pointdouble 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;}//Celsius to Fahrenheit conversionfloat Fahrenheit(float celsius){  return 1.8 * celsius + 32;}`

duckie

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