first commit

Software/CSharp/GrovePi/Sensors/TemperatureAndHumiditySensor.cs

@@ -0,0 +1,46 @@
+using System;
+
+namespace GrovePi.Sensors
+{
+    public interface ITemperatureAndHumiditySensor
+    {
+        double TemperatureInCelsius();
+    }
+
+    /// <summary>
+    /// Specifies the model of sensor. 
+    /// DHT11 - blue one - comes with the GrovePi+ Starter Kit.
+    /// DHT22 - white one, aka DHT Pro or AM2302.
+    /// DHT21 - black one, aka AM2301.
+    /// </summary>
+    public enum Model
+    {
+        /* 
+        */
+        Dht11 = 3975,
+        Dht21 = 4250,
+        Dht22 = 4250
+    }
+
+    internal class TemperatureAndHumiditySensor : ITemperatureAndHumiditySensor
+    {
+        private readonly IGrovePi _device;
+        private readonly Model _model;
+        private readonly Pin _pin;
+
+        internal TemperatureAndHumiditySensor(IGrovePi device, Pin pin, Model model)
+        {
+            if (device == null) throw new ArgumentNullException(nameof(device));
+            _device = device;
+            _pin = pin;
+            _model = model;
+        }
+
+        public double TemperatureInCelsius()
+        {
+            var result = (double) _device.AnalogRead(_pin);
+            var resistance = (1023 - result)*10000/result;
+            return 1/(Math.Log(resistance/10000)/(int) _model + 1/298.15) - 273.15;
+        }
+    }
+}