first commit

Software/CSharp/GrovePi/Sensors/UltrasonicRangerSensor.cs

@@ -0,0 +1,40 @@
+using GrovePi.Common;
+
+namespace GrovePi.Sensors
+{
+    public interface IUltrasonicRangerSensor
+    {
+        int MeasureInCentimeters();
+    }
+
+    internal class UltrasonicRangerSensor : IUltrasonicRangerSensor
+    {
+        private const byte CommandAddress = 7;
+        private readonly GrovePi _device;
+        private readonly Pin _pin;
+
+        internal UltrasonicRangerSensor(GrovePi device, Pin pin)
+        {
+            _device = device;
+            _pin = pin;
+        }
+
+        public int MeasureInCentimeters()
+        {
+            var buffer = new byte[4] {CommandAddress, (byte) _pin, Constants.Unused, Constants.Unused};
+            var result = _device.DirectAccess.WritePartial(buffer);
+            if (result.Status != Windows.Devices.I2c.I2cTransferStatus.FullTransfer)
+            {
+                return -1;
+            }
+            Delay.Milliseconds(50);
+            buffer = new byte[3];
+            result = _device.DirectAccess.ReadPartial(buffer);
+            if (result.Status != Windows.Devices.I2c.I2cTransferStatus.FullTransfer)
+            {
+                return -1;
+            }
+            return buffer[1]*256 + buffer[2];
+        }
+    }
+}