Bump library to 1.2.2 version.

As correctly stated by Mausy5043, the division is quite slow in most
microcontrollers, so I have replaced them with multiplications.

DHT.cpp

@@ -46,7 +46,7 @@ float DHT::readTemperature(bool S, bool force) {
       f = data[2] & 0x7F;
       f *= 256;
       f += data[3];
-      f /= 10;
+      f *= 0.1;
       if (data[2] & 0x80) {
         f *= -1;
       }
@@ -60,11 +60,11 @@ float DHT::readTemperature(bool S, bool force) {
 }
 
 float DHT::convertCtoF(float c) {
-  return c * 9 / 5 + 32;
+  return c * 1.8 + 32;
 }
 
 float DHT::convertFtoC(float f) {
-  return (f - 32) * 5 / 9;
+  return (f - 32) * 0.55555;
 }
 
 float DHT::readHumidity(bool force) {
@@ -79,7 +79,7 @@ float DHT::readHumidity(bool force) {
       f = data[0];
       f *= 256;
       f += data[1];
-      f /= 10;
+      f *= 0.1;
       break;
     }
   }
@@ -88,23 +88,17 @@ float DHT::readHumidity(bool force) {
 
 //boolean isFahrenheit: True == Fahrenheit; False == Celcius
 float DHT::computeHeatIndex(float temperature, float percentHumidity, bool isFahrenheit) {
-  // Adapted from equation at: https://github.com/adafruit/DHT-sensor-library/issues/9 and
-  // Wikipedia: http://en.wikipedia.org/wiki/Heat_index
-  if (!isFahrenheit) {
-    // Celsius heat index calculation.
-    return -8.784695 +
-             1.61139411 * temperature +
-             2.338549   * percentHumidity +
-            -0.14611605 * temperature*percentHumidity +
-            -0.01230809 * pow(temperature, 2) +
-            -0.01642482 * pow(percentHumidity, 2) +
-             0.00221173 * pow(temperature, 2) * percentHumidity +
-             0.00072546 * temperature*pow(percentHumidity, 2) +
-            -0.00000358 * pow(temperature, 2) * pow(percentHumidity, 2);
-  }
-  else {
-    // Fahrenheit heat index calculation.
-    return -42.379 +
+  // Using both Rothfusz and Steadman's equations
+  // http://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml
+  float hi;
+
+  if (!isFahrenheit)
+    temperature = convertCtoF(temperature);
+
+  hi = 0.5 * (temperature + 61.0 + ((temperature - 68.0) * 1.2) + (percentHumidity * 0.094)); 
+
+  if (hi > 79) {
+    hi = -42.379 +
              2.04901523 * temperature +
             10.14333127 * percentHumidity +
             -0.22475541 * temperature*percentHumidity +
@@ -113,7 +107,15 @@ float DHT::computeHeatIndex(float temperature, float percentHumidity, bool isFah
              0.00122874 * pow(temperature, 2) * percentHumidity +
              0.00085282 * temperature*pow(percentHumidity, 2) +
             -0.00000199 * pow(temperature, 2) * pow(percentHumidity, 2);
+
+    if((percentHumidity < 13) && (temperature >= 80.0) && (temperature <= 112.0))
+      hi -= ((13.0 - percentHumidity) * 0.25) * sqrt((17.0 - abs(temperature - 95.0)) * 0.05882);
+
+    else if((percentHumidity > 85.0) && (temperature >= 80.0) && (temperature <= 87.0))
+      hi += ((percentHumidity - 85.0) * 0.1) * ((87.0 - temperature) * 0.2);
   }
+
+  return isFahrenheit ? hi : convertFtoC(hi);
 }
 
 boolean DHT::read(bool force) {

library.properties

@@ -1,5 +1,5 @@
 name=DHT sensor library
-version=1.2.0
+version=1.2.2
 author=Adafruit
 maintainer=Adafruit <info@adafruit.com>
 sentence=Arduino library for DHT11, DHT22, etc Temp & Humidity Sensors