Added LLC200D3SH binding (#1090)

* Add Llc200d3sh device

Adding a binding for the LLC200D3SH Optomax digital liquid level switch

* Update README.md

Correct spelling mistake

* Code Review Changes

Updates from pull request code review

* Remove code

Remove copy of old code

* Update README.md

Update readme file

* Update README.md

Update readme

* Code Review Changes

Changes from the code review

* Code Review Changes

Changes from code review
Co-authored-by: NDarren Fahy <dfahy@tvcl.co.uk>

src/devices/LiquidLevel/LiquidLevel.csproj

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+
+  <ItemGroup>
+    <Compile Include="*.cs" />
+    <Compile Remove="samples\**" />
+    <None Include="README.md" />
+	  <ProjectReference Include="$(MainLibraryPath)System.Device.Gpio.csproj" />
+  </ItemGroup>
+  
+</Project>

src/devices/LiquidLevel/LiquidLevel.sln

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src/devices/LiquidLevel/LiquidLevelSwitch.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Device.Gpio;
+
+namespace Iot.Device.LiquidLevel
+{
+    /// <summary>
+    /// Supports any single pin output digital liquid level switch which is configured
+    /// </summary>
+    public class LiquidLevelSwitch : IDisposable
+    {
+        private readonly int _dataPin;
+        private readonly PinValue _liquidPresentPinState;
+        private readonly bool _shouldDispose;
+
+        private GpioController _controller;
+
+        /// <summary>Creates a new instance of the LiquidLevelSwitch.</summary>
+        /// <param name="dataPin">The data pin</param>
+        /// <param name="liquidPresentPinState">Data pin state representing liquid being present</param>
+        /// <param name="pinNumberingScheme">Use the logical or physical pin layout</param>
+        /// <param name="gpioController">A Gpio Controller if you want to use a specific one</param>
+        /// <param name="shouldDispose">True to dispose the Gpio Controller</param>
+        public LiquidLevelSwitch(int dataPin, PinValue liquidPresentPinState, GpioController gpioController = null, PinNumberingScheme pinNumberingScheme = PinNumberingScheme.Logical, bool shouldDispose = true)
+        {
+            _controller = gpioController ?? new GpioController(pinNumberingScheme);
+            _dataPin = dataPin;
+            _liquidPresentPinState = liquidPresentPinState;
+
+            _controller.OpenPin(_dataPin, PinMode.Input);
+
+            _shouldDispose = shouldDispose || gpioController == null;
+        }
+
+        /// <summary>
+        /// Determines whether liquid is present.
+        /// </summary>
+        /// <returns><code>true</code> if liquid is present, otherwise <code>false</code>.</returns>
+        public bool IsLiquidPresent()
+        {
+            return _controller.Read(_dataPin) == _liquidPresentPinState;
+        }
+
+        /// <summary>
+        /// Dispose Buzzer.
+        /// </summary>
+        public void Dispose()
+        {
+            if (_shouldDispose)
+            {
+                _controller?.Dispose();
+                _controller = null;
+            }
+        }
+    }
+}

src/devices/LiquidLevel/Llc200d3sh.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Device.Gpio;
+
+namespace Iot.Device.LiquidLevel
+{
+    /// <summary>
+    /// Optomax LLC200D3SH digital liquid level switch
+    /// </summary>
+    public class Llc200d3sh : LiquidLevelSwitch
+    {
+        /// <summary>Creates a new instance of the Llc200d3sh.</summary>
+        /// <param name="pin">The data pin</param>
+        /// <param name="pinNumberingScheme">Use the logical or physical pin layout</param>
+        /// <param name="gpioController">A Gpio Controller if you want to use a specific one</param>
+        /// <param name="shouldDispose">True to dispose the Gpio Controller</param>
+        public Llc200d3sh(int pin, GpioController gpioController = null, PinNumberingScheme pinNumberingScheme = PinNumberingScheme.Logical, bool shouldDispose = true)
+            : base(pin, PinValue.Low, gpioController, pinNumberingScheme, shouldDispose)
+        {
+        }
+    }
+}

src/devices/LiquidLevel/README.md

+# Digital liquid level switch
+
+Digital liquid level switches are devices that can detect the presence of liquid/water. GPIO can be used to communicate with the devices.
+
+## Device Family
+
+The implementation supports any single pin output digital liquid level switch.
+
+## Usage
+```c#
+using (LiquidLevelSwitch sensor = new LiquidLevelSwitch(23, PinValue.Low))
+{
+    while (true)
+    {
+        // read liquid level switch
+        Console.WriteLine($"Detected: {sensor.IsLiquidPresent()}");
+        Console.WriteLine();
+
+        Thread.Sleep(1000);
+    }
+}
+```
+
+An example on how to use the specific LLC200D3SH device binding is available in the [samples](samples) folder.

src/devices/LiquidLevel/samples/LiquidLevelSwitch.Sample.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <EnableDefaultItems>false</EnableDefaultItems>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Remove="rpi-llc200d3sh.fzz" />
+    <None Remove="rpi-llc200d3sh_bb.png" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Compile Include="LiquidLevelSwitch.sample.cs" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\LiquidLevel.csproj" />
+    <ProjectReference Include="$(MainLibraryPath)System.Device.Gpio.csproj" />
+  </ItemGroup>
+  
+</Project>

src/devices/LiquidLevel/samples/LiquidLevelSwitch.sample.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Device.Gpio;
+using System.Threading;
+using Iot.Device.LiquidLevel;
+
+namespace LiquidLevel.Sample
+{
+    internal class Program
+    {
+        public static void Main(string[] args)
+        {
+            using (LiquidLevelSwitch sensor = new LiquidLevelSwitch(23, PinValue.Low))
+            {
+                while (true)
+                {
+                    // read liquid level switch
+                    Console.WriteLine($"Detected: {sensor.IsLiquidPresent()}");
+                    Console.WriteLine();
+
+                    Thread.Sleep(1000);
+                }
+            }
+        }
+    }
+}

src/devices/LiquidLevel/samples/Llc200d3sh.Sample.csproj

+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <EnableDefaultItems>false</EnableDefaultItems>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Remove="rpi-llc200d3sh.fzz" />
+    <None Remove="rpi-llc200d3sh_bb.png" />
+  </ItemGroup>
+  
+  <ItemGroup>
+    <Compile Include="Llc200d3sh.sample.cs" />
+  </ItemGroup>
+  
+  <ItemGroup>
+    <ProjectReference Include="..\LiquidLevel.csproj" />
+    <ProjectReference Include="$(MainLibraryPath)System.Device.Gpio.csproj" />
+  </ItemGroup>
+  
+</Project>

src/devices/LiquidLevel/samples/Llc200d3sh.sample.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Threading;
+
+namespace Iot.Device.LiquidLevel.Samples
+{
+    internal class Program
+    {
+        public static void Main(string[] args)
+        {
+            using (Llc200d3sh sensor = new Llc200d3sh(23))
+            {
+                while (true)
+                {
+                    // read liquid level switch
+                    Console.WriteLine($"Detected: {sensor.IsLiquidPresent()}");
+                    Console.WriteLine();
+
+                    Thread.Sleep(1000);
+                }
+            }
+        }
+    }
+}

src/devices/LiquidLevel/samples/README.md

+# Digital liquid level switch Samples
+
+## LLC200D3SH Circuit
+
+The following fritzing diagram illustrates one way to wire up the Optomax LLC200D3SH digital liquid level switch with a Raspberry Pi.
+
+![Raspberry Pi Breadboard diagram](rpi-llc200d3sh_bb.png)
+
+## Code
+
+Define the LLC200D3SH sensor using the LiquidLevelSwitch class.
+
+```C#
+using (Llc200d3sh sensor = new Llc200d3sh(23))
+{
+    while (true)
+    {
+        // read liquid level switch
+        Console.WriteLine($"Detected: {sensor.IsLiquidPresent()}");
+        Console.WriteLine();
+
+        Thread.Sleep(1000);
+    }
+}
+```
+
+## References
+
+- LLC200D3SH sensor ([Datasheet](https://cdn-shop.adafruit.com/product-files/3397/3397_datasheet_actual.pdf))