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Adding a simple Dew Point function to Adafruit DHT library

Open TeddyMcSnuggins opened this issue 4 months ago • 2 comments

Hi. I am an astronomer/astrophotographer. I am currently building a control board for my Celestron telescope and one of the metrics I want to collect is the Dew Point. I will use this in deciding the power level I will supply to my Dew Heater on the telescope. I have found a simple Dew Point calculation, which would be great to be able to reference from a DHT sensor. The calculation can be found at https://iridl.ldeo.columbia.edu/dochelp/QA/Basic/dewpoint.html.

Would this be something that you would consider adding to the current library? I have provided my code below for your reference. This was tested on the following:

  • Arduino board: *ARDUINO/UNO R3
  • Arduino IDE version (found in Arduino -> About Arduino menu): 1.8.19
  • Adafruit DHT11 and DHT22 sensors

DHT.h float computeDewPointSimple(float temperature, float percentHumidity, bool isFahrenheit = true);

DHT.cpp /*!

  • @brief Compute Dew Point - Simple Method

  •  			Using formula was proposed in a 2005 article by Mark G. Lawrence in the Bulletin of the American Meteorological Society:
    
  •  			(https://iridl.ldeo.columbia.edu/dochelp/QA/Basic/dewpoint.html)
    
  • @param temperature

  •      temperature in selected scale
    
  • @param percentHumidity

  •      humidity in percent
    
  • @param isFahrenheit

  •  			true if fahrenheit, false if celcius
    
  • @return float dew point */ float DHT::computeDewPointSimple(float temperature, float percentHumidity, bool isFahrenheit) {

    float hi;

if (!isFahrenheit) temperature = convertCtoF(temperature);

hi = temperature-((100 - percentHumidity) / 5);

return isFahrenheit ? hi : convertFtoC(hi);

}

There is a more complex function that gives greater accuracy, which is detailed on the web page provided above, but I have yet compiled that function.

Kind regards Teddy

TeddyMcSnuggins avatar Sep 29 '24 06:09 TeddyMcSnuggins