add absoluteHumidity + boiling functions (#20)

- add **absoluteHumidity(TC, RH)** from relative humidity
- add **boilingFahrenheit(feet)** boiling temperature Fahrenheit at height in feet.
- add **boilingCelsius(meter)** boiling temperature Celsius at height in meter.
- add **boilingMeter(Celsius)** inverse function of above.
- add example
- update keywords.txt
- update readme.md
- update GitHub actions
- update license 2023
- minor edits

CHANGELOG.md

@@ -6,13 +6,25 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.3.6] - 2023-02-17
+- add **absoluteHumidity(TC, RH)** from relative humidity
+- add **boilingFahrenheit(feet)** boiling temperature Fahrenheit at height in feet.
+- add **boilingCelsius(meter)** boiling temperature Celsius at height in meter.
+- add **boilingMeter(Celsius)** inverse function of above.
+- add example
+- update keywords.txt
+- update readme.md
+- update GitHub actions
+- update license 2023
+- minor edits
+
+
 ## [0.3.5] - 2022-11-26
 - added RP2040 to build-CI
 - simplified changelog
 - optimized Steadman's formula (HeatIndex).
 - update readme.md
 
-
 ## [0.3.4] - 2022-04-15
 - fix #16 Split .h in .h and .cpp 
 

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017-2023 Rob Tillaart
+Copyright (c) 2015-2023 Rob Tillaart
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -24,6 +24,9 @@ Note: pre-0.3.1 versions have incorrect heat-index.
 
 ## Interface
 
+```cpp
+#include "temperature.h"
+```
 
 ### Conversion
 
@@ -65,6 +68,13 @@ Indicative table
 |   > 130      |   > 54    |  extreme hot  |    purple     |
 
 
+### Absolute Humidity
+
+- **float absoluteHumidity(float Celsius, float relHumidity)**
+Converts relative humidity and temperature to absolute humidity.
+Return unit is grams/m3.
+
+
 ### WindChill
 
 Wind speed @ 10 meter, if **convert** is true => wind speed will be converted to 1.5 meter
@@ -86,9 +96,33 @@ Indicative table (subjective).
 |    < -55        |  serious dangerous     |
 
 
+### Boiling temperature water
+
+When you are in the mountains the cooking point of water drops.
+This can be so much that you can't boil an egg on mount Everest.
+
+Temperature in F and C at which water cooks.
+Based upon: https://en.wikipedia.org/wiki/High-altitude_cooking
+
+- **boilingFahrenheit(feet)** boiling temperature Fahrenheit at height in feet.
+- **boilingCelsius(meter)** boiling temperature Celsius at height in meter.
+- **boilingMeter(Celsius)** returns height in meters for a given the boiling point in Celsius.
+Note this is an approximation by reversing the formula.
+Do not expect it to be very exact.
+
+
+For Celsius from feet call:
+```cpp
+C = boilingCelsius(feet * 0.3048);
+```
+For Fahrenheit from meters call:
+```cpp
+F = boilingFahrenheit(meter * 3.2808);  //  * 3.280839895  == / 0.3048
+```
+
 ----
 
-# temperatureConverter class
+# TemperatureConverter class
 
 Since version 0.3.2 a temperature convertor class is added to convert to and from 
 other (less known) temperature scales. 
@@ -118,6 +152,10 @@ prevents to have 8 x 7 optimized functions.
 
 ## Interface
 
+```cpp
+#include "temperature.h"
+```
+
 #### Constructor
 
 - **temperatureConverter()** Constructor sets the default to zero degrees C.
@@ -158,14 +196,24 @@ See examples for typical usage.
 
 # Future
 
-#### must
+#### Must
+
+- split of TemperatureConversion class as a library of its own.
+  - 0.4.0
+
+#### Should
 
-#### should
 - improve documentation
-  - add short explanation?
-- add formula for water boiling height 
-  - https://en.wikipedia.org/wiki/High-altitude_cooking
-  - multiMap needed?
+  - add short explanation per conversion unit? 
+  - freeze/boil temps.
+- unit tests
+  - absoluteHumidity
+  - boiling tests.
+
+#### Could
+
+- TEMPERATURE_VERSION => TEMPERATURE_LIB_VERSION
+  - when split of the converter? 0.4.0
 
-#### could
+#### Wont
 

examples/boilingPoint_test/boilingPoint_test.ino

@@ -0,0 +1,73 @@
+//
+//    FILE: boilingPoint_test.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: Demo for boiling point formula
+//     URL: https://github.com/RobTillaart/Temperature
+//
+
+
+#include "temperature.h"
+
+uint32_t stop, start;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("TEMPERATURE_VERSION: ");
+  Serial.println(TEMPERATURE_VERSION);
+  Serial.println();
+
+  for (int meters = 0; meters < 5000; meters += 100)
+  {
+    Serial.print(meters);
+    Serial.print("\t");
+    Serial.print(boilingCelsius(meters));
+    Serial.print("\t");
+    Serial.print(boilingFahrenheit(meters * 3.2808));
+    Serial.print("\n");
+  }
+  Serial.println();
+
+
+  for (int feet = 0; feet <= 15000; feet += 100)
+  {
+    Serial.print(feet);
+    Serial.print("\t");
+    Serial.print(boilingCelsius(feet * 0.3048));
+    Serial.print("\t");
+    Serial.print(boilingFahrenheit(feet));
+    Serial.print("\n");
+  }
+  Serial.println();
+
+
+  for (float temp = 100; temp >= 80; temp -= 1)
+  {
+    Serial.print(temp);
+    Serial.print("\t");
+    Serial.print(boilingMeter(temp));
+    Serial.print("\n");
+  }
+  Serial.println();
+
+  for (float temp = 100; temp >= 98; temp -= 0.1)
+  {
+    Serial.print(temp);
+    Serial.print("\t");
+    Serial.print(boilingMeter(temp));
+    Serial.print("\n");
+  }
+  Serial.println();
+
+}
+
+
+void loop()
+{
+
+}
+
+
+//  -- END OF FILE --

keywords.txt

@@ -9,15 +9,25 @@ temperatureConverter	KEYWORD1
 Fahrenheit	KEYWORD2
 Celsius	KEYWORD2
 Kelvin	KEYWORD2
+
 dewPoint	KEYWORD2
 dewPointFast	KEYWORD2
 humidex	KEYWORD2
+
 heatIndex	KEYWORD2
 heatIndexC	KEYWORD2
+
 WindChill_F_mph	KEYWORD2
 WindChill_C_kmph	KEYWORD2
 WindChill_C_mps	KEYWORD2
 
+absoluteHumidity	KEYWORD2
+
+boilingFahrenheit	KEYWORD2
+boilingCelsius	KEYWORD2
+boilingMeter	KEYWORD2
+
+
 
 # temperatureConverter class
 setKelvin	KEYWORD2

library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/Temperature"
   },
-  "version": "0.3.5",
+  "version": "0.3.6",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",

library.properties

@@ -1,5 +1,5 @@
 name=Temperature
-version=0.3.5
+version=0.3.6
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Library with weather and temperature conversion functions.

temperature.cpp

@@ -1,8 +1,10 @@
 //
 //    FILE: temperature.cpp
-// VERSION: 0.3.5
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.3.6
 //    DATE: 2015-03-29
 // PURPOSE: collection temperature functions
+//     URL: https://github.com/RobTillaart/Temperature
 
 
 #include "temperature.h"
@@ -74,7 +76,7 @@ float humidex(float celsius, float dewPoint)
 }
 
 
-//  0.3.0 => https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml 
+//  0.3.0 => https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml
 //           previous  https://en.wikipedia.org/wiki/Heat_index
 //  TF = temp in Fahrenheit
 //  RH = relative humidity in %
@@ -118,7 +120,7 @@ float heatIndex(float TF, float RH)
 }
 
 
-//  0.3.0 => https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml 
+//  0.3.0 => https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml
 //           previous  https://en.wikipedia.org/wiki/Heat_index
 //  TC = temp in Celsius
 //  RH = relative humidity in %
@@ -148,6 +150,21 @@ float heatIndexC(float TC, float RH)
 }
 
 
+//  https://carnotcycle.wordpress.com/2012/08/04/how-to-convert-relative-humidity-to-absolute-humidity/
+//  Absolute Humidity (grams/m3) = 6.112 × e^[(17.67 × T)/(T+243.5)] × rh × 2.1674
+//                                 -----------------------------------------------
+//                                                 (273.15+T)
+float absoluteHumidity(float Celsius, float relHumidity)
+{
+  float TC = Celsius;
+  float AH = (2.1674 * 6.112) * relHumidity;
+  AH *= exp((17.67 * TC)/(243.5 + TC));
+  AH /=  (273.15 + TC);
+  return AH;
+}
+
+
+
 //  https://en.wikipedia.org/wiki/Wind_chill
 //     US     = Fahrenheit / miles / hour
 //     METRIC = Celsius    / meter / hour (sec)
@@ -217,5 +234,27 @@ float altitudeToSeaLevel( float pressure, float celsius, float altitude)
 }
 
 
+//  https://en.wikipedia.org/wiki/High-altitude_cooking
+float boilingFahrenheit(float feet)
+{
+  if (feet >= 0) return 212.1309 - feet * 1.86176954e-3;
+  return 212;
+}
+
+
+float boilingCelsius(float meter)
+{
+  if (meter > 0) return 100.08143 - meter * 3.39670635e-3;
+  return 100;
+}
+
+//  Celsius = 80..100
+float boilingMeter(float Celsius)
+{
+  if (Celsius >= 100) return 0;
+  return 29458.542 - Celsius * 294.34149;
+}
+
+
 //  -- END OF FILE --
 

temperature.h

@@ -1,15 +1,17 @@
 #pragma once
 //
 //    FILE: temperature.h
-// VERSION: 0.3.5
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.3.6
 //    DATE: 2015-03-29
 // PURPOSE: collection temperature functions
+//     URL: https://github.com/RobTillaart/Temperature
 
 
 #include "Arduino.h"
 
 
-#define TEMPERATURE_VERSION         (F("0.3.5"))
+#define TEMPERATURE_VERSION         (F("0.3.6"))
 
 
 float Fahrenheit(float celsius);
@@ -56,6 +58,12 @@ float heatIndex(float TF, float RH);
 float heatIndexC(float TC, float RH);
 
 
+//  https://carnotcycle.wordpress.com/2012/08/04/how-to-convert-relative-humidity-to-absolute-humidity/
+//  Absolute Humidity (grams/m3) = 6.112 × e^[(17.67 × T)/(T+243.5)] × rh × 2.1674
+//                                 -----------------------------------------------
+//                                                 (273.15+T)
+float absoluteHumidity(float Celsius, float relHumidity);
+
 
 //  https://en.wikipedia.org/wiki/Wind_chill
 //     US     = Fahrenheit / miles / hour
@@ -90,7 +98,20 @@ float altitudeToSeaLevel( float pressure, float celsius, float altitude);
 
 
 
-/////////////////////////////////////////////////////////////
+//  https://en.wikipedia.org/wiki/High-altitude_cooking
+//  temperature at which water cooks
+//  1 feet = 0.3048 meter
+float boilingFahrenheit(float feet);   //  feet  = 0..15000
+float boilingCelsius(float meter);     //  meter = 0..4500 
+
+//  inverse function 
+//  Celsius = 80°..100°
+float boilingMeter(float Celsius);
+
+
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
 //
 //  TEMPERATURE CONVERTER CLASS
 //