Realtime air temperature measuring added

pumpkin-motion-trigger.ino

@@ -1,9 +1,36 @@
+class Thermistor
+{
+  int analogPin;
+
+  public:
+  Thermistor(int analogPin)
+  {
+    this->analogPin = analogPin;
+    pinMode(analogPin, INPUT);
+  }
+
+  double getDegrees()
+  {
+    double temp = log(10000.0 * (1024.0 / analogRead(this->analogPin) - 1));
+    temp = 1 / (0.001129148 + (0.000234125 + (0.0000000876741 * temp * temp)) * temp) - 273.15;
+
+    return temp;
+  }
+};
+
+Thermistor thermistor(15);
+
 class HCSR04
 {
   int pinTrigger;
   int pinEcho;
   double soundMetresPerMillisecond = 0.343;
 
+  double getMetersPerMillisecond()
+  {
+    return (331 + 0.6 * thermistor.getDegrees()) / 1000.0;
+  }
+
   public:
   HCSR04(int pinTrigger, int pinEcho)
   {
@@ -27,7 +54,7 @@ class HCSR04
 
   double getMetres()
   {
-    return this->getMilliseconds() * this->soundMetresPerMillisecond * 0.5;
+    return this->getMilliseconds() * this->getMetersPerMillisecond() * 0.5;
   }
 
   double getCentimeters()