SGP40 sensor driver

Source/Meadow.Foundation.Peripherals/Sensors.Atmospheric.Sgp40/Driver/Sensors.Atmospheric.Sgp40.csproj

@@ -0,0 +1,32 @@
+<Project Sdk="Meadow.Sdk/1.1.0">
+  <PropertyGroup>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+    <PackageIcon>icon.png</PackageIcon>
+    <Authors>Wilderness Labs, Inc</Authors>
+    <TargetFramework>netstandard2.1</TargetFramework>
+    <OutputType>Library</OutputType>
+    <AssemblyName>Sgp40</AssemblyName>
+    <Company>Wilderness Labs, Inc</Company>
+    <PackageProjectUrl>http://developer.wildernesslabs.co/Meadow/Meadow.Foundation/</PackageProjectUrl>
+    <PackageId>Meadow.Foundation.Sensors.Atmospheric.Sgp40</PackageId>
+    <RepositoryUrl>https://github.com/WildernessLabs/Meadow.Foundation</RepositoryUrl>
+    <PackageTags>Meadow.Foundation, Atmospheric, SGP40, Sensiron</PackageTags>
+    <Version>0.1.44</Version>
+    <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
+    <Description>SGP40 VOC sensor driver</Description>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <LangVersion>8.0</LangVersion>
+    <DefineConstants>TRACE;JETSON</DefineConstants>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <LangVersion>8.0</LangVersion>
+  </PropertyGroup>
+  <ItemGroup>
+    <None Include="..\..\..\icon.png" Pack="true" PackagePath="" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Meadow.Foundation" Version="0.33.1" />
+  </ItemGroup>
+</Project>

Source/Meadow.Foundation.Peripherals/Sensors.Atmospheric.Sgp40/Driver/Sgp40.Enums.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace Meadow.Foundation.Sensors.Atmospheric
+{
+    public partial class Sgp40
+    {
+        /// <summary>
+        /// Valid addresses for the sensor
+        /// </summary>
+        public enum Address : byte
+        {
+            /// <summary>
+            /// Bus address 0x59
+            /// </summary>
+            Address_0x59 = 0x59,
+            /// <summary>
+            /// Bus address 0x59
+            /// </summary>
+            Default = Address_0x59
+        }
+
+        private static byte[] sgp40_measure_raw_signal = { 0x26, 0x0f };
+        private static byte[] sgp40_measure_raw_signal_uncompensated = { 0x26, 0x0F, 0x80, 0x00, 0xA2, 0x66, 0x66, 0x93 };
+        private static byte[] sgp40_execute_self_test = { 0x28, 0x0e };
+        private static byte[] sgp4x_turn_heater_off = { 0x36, 0x15 };
+        private static byte[] sgp4x_get_serial_number = { 0x36, 0x82 };
+
+    }
+}

Source/Meadow.Foundation.Peripherals/Sensors.Atmospheric.Sgp40/Driver/Sgp40.cs

@@ -0,0 +1,164 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using Meadow.Hardware;
+using Meadow.Peripherals.Sensors;
+using Meadow.Units;
+using HU = Meadow.Units.RelativeHumidity.UnitType;
+using TU = Meadow.Units.Temperature.UnitType;
+
+namespace Meadow.Foundation.Sensors.Atmospheric
+{
+    /// <summary>
+    /// Provides access to the Sensiron SGP40 VOC sensor
+    /// </summary>
+    public partial class Sgp40 :
+        ByteCommsSensorBase<int>
+    {
+        /// <summary>
+        /// </summary>
+        public event EventHandler<ChangeResult<int>> VocIndexUpdated = delegate { };
+
+        /// <summary>
+        /// The VOC Index, from the last reading.
+        /// </summary>
+        public int VocIndex => Conditions;
+
+        /// <summary>
+        /// Serial number of the device.
+        /// </summary>
+        public ulong SerialNumber { get; private set; }
+
+        private byte[]? _compensationData = null;
+
+        /// <summary>
+        /// Creates a new SGP40 VOC sensor.
+        /// </summary>
+        /// <param name="address">Sensor address (default to 0x40).</param>
+        /// <param name="i2cBus">I2CBus.</param>
+        public Sgp40(II2cBus i2cBus, byte address = (byte)Address.Default)
+            : base(i2cBus, address, 9, 8)
+        {
+            Initialize();
+        }
+
+        protected void Initialize()
+        {
+            // write buffer for initialization commands only can be two bytes.
+            Span<byte> tx = WriteBuffer.Span[0..2];
+
+            Peripheral.Write(sgp4x_get_serial_number);
+
+            Thread.Sleep(1); // per the data sheet
+
+            Peripheral.Read(ReadBuffer.Span[0..9]);
+
+            var bytes = ReadBuffer.ToArray();
+
+            SerialNumber = (ulong)(bytes[0] << 40 | bytes[1] << 32 | bytes[3] << 24 | bytes[4] << 16 | bytes[6] << 8 | bytes[7] << 0);
+        }
+
+        /// <summary>
+        /// This command triggers the built-in self-test checking for integrity of both hotplate and MOX material
+        /// </summary>
+        /// <returns>true on sucessful test, otherwise false</returns>
+        public bool RunSelfTest()
+        {
+            Peripheral.Write(sgp40_execute_self_test);
+
+            Thread.Sleep(325); // test requires 320ms to complete
+
+            Peripheral.Read(ReadBuffer.Span[0..3]);
+
+            return ReadBuffer.Span[0..1][0] == 0xd4;
+        }
+
+        protected async override Task<int> ReadSensor()
+        {
+            return await Task.Run(() =>
+            {
+                if(_compensationData != null)
+                {
+                    Peripheral.Write(_compensationData);
+                }
+                else
+                {
+                    Peripheral.Write(sgp40_measure_raw_signal_uncompensated);
+                }
+
+                Thread.Sleep(30); // per the data sheet
+
+                Peripheral.Read(ReadBuffer.Span[0..3]);
+
+                var data = ReadBuffer.Span[0..3].ToArray();
+
+                return data[0] << 8 | data[1];
+            });
+        }
+
+        /// <summary>
+        /// Inheritance-safe way to raise events and notify observers.
+        /// </summary>
+        /// <param name="changeResult"></param>
+        protected override void RaiseEventsAndNotify(IChangeResult<int> changeResult)
+        {
+            VocIndexUpdated?.Invoke(this, new ChangeResult<int>(VocIndex, changeResult.Old));
+
+            base.RaiseEventsAndNotify(changeResult);
+        }
+
+        /// <summary>
+        /// This command turns the hotplate off and stops the measurement. Subsequently, the sensor enters idle mode.
+        /// </summary>
+        public void TurnHeaterOff()
+        {
+            Peripheral.Write(sgp4x_turn_heater_off);
+        }
+
+        public void SetCompensationData(RelativeHumidity humidity, Meadow.Units.Temperature temperature)
+        {
+            _compensationData = new byte[8];
+
+            Array.Copy(sgp40_measure_raw_signal, 0, _compensationData, 0, 2);
+
+            var rh = BitConverter.GetBytes(System.Net.IPAddress.HostToNetworkOrder((ushort)(humidity.Percent * 65535 / 100)));
+            _compensationData[2] = rh[0];
+            _compensationData[3] = rh[1];
+            _compensationData[4] = Crc(rh);
+
+            var t = BitConverter.GetBytes(System.Net.IPAddress.HostToNetworkOrder((ushort)(temperature.Celsius * 65535 / 175)));
+            _compensationData[5] = t[0];
+            _compensationData[6] = t[1];
+            _compensationData[7] = Crc(t);
+
+        }
+
+        public void ClearCompensationData()
+        {
+            _compensationData = null;
+        }
+
+        private byte Crc(byte[] data)
+        {
+            if (data.Length != 2) throw new ArgumentException();
+
+            byte crc = 0xFF;
+            for (int i = 0; i < 2; i++)
+            {
+                crc ^= data[i];
+                for (byte bit = 8; bit > 0; --bit)
+                {
+                    if ((crc & 0x80) != 0)
+                    {
+                        crc = (byte)((crc << 1) ^ 0x31);
+                    }
+                    else
+                    {
+                        crc = (byte)(crc << 1);
+                    }
+                }
+            }
+            return crc;
+        }
+    }
+}

Source/Meadow.Foundation.Peripherals/Sensors.Atmospheric.Sgp40/Samples/Sgp40_Sample/MeadowApp.cs

@@ -0,0 +1,73 @@
+using Meadow;
+using Meadow.Devices;
+using Meadow.Foundation.Sensors.Atmospheric;
+using System;
+using System.Threading.Tasks;
+
+namespace BasicSensors.Atmospheric.SI7021_Sample
+{
+    public class MeadowApp : App<F7FeatherV1>
+    {
+        //<!=SNIP=>
+
+        Sgp40 sensor;
+
+        public MeadowApp()
+        {
+        }
+
+        public override Task Initialize()
+        {
+            Resolver.Log.Info("Initializing...");
+
+            sensor = new Sgp40(Device.CreateI2cBus());
+
+            Resolver.Log.Info($"Sensor SN: {sensor.SerialNumber:x6}");
+
+            if (sensor.RunSelfTest())
+            {
+                Resolver.Log.Info("Self test successful");
+            }
+            else
+            {
+                Resolver.Log.Warn("Self test failed");
+            }
+
+            var consumer = Sgp40.CreateObserver(
+                handler: result =>
+                {
+                    Resolver.Log.Info($"Observer: VOC changed by threshold; new index: {result.New}");
+                },
+                filter: result =>
+                {
+                    //c# 8 pattern match syntax. checks for !null and assigns var.
+                    return Math.Abs(result.New - result.Old ?? 0) > 10;
+                }
+            );
+            sensor.Subscribe(consumer);
+
+            sensor.Updated += (sender, result) =>
+            {
+                Resolver.Log.Info($"  VOC: {result.New}");
+            };
+
+            return base.Initialize();
+        }
+
+        public override async Task Run()
+        {
+            await ReadConditions();
+
+            sensor.StartUpdating(TimeSpan.FromSeconds(1));
+        }
+
+        async Task ReadConditions()
+        {
+            var result = await sensor.Read();
+            Resolver.Log.Info("Initial Readings:");
+            Resolver.Log.Info($"  Temperature: {result}");
+        }
+
+        //<!=SNOP=>
+    }
+}

Source/Meadow.Foundation.Peripherals/Sensors.Atmospheric.Sgp40/Samples/Sgp40_Sample/Program.cs

@@ -0,0 +1,17 @@
+using Meadow;
+using System.Threading;
+
+namespace BasicSensors.Atmospheric.SI7021_Sample
+{
+    class Program
+    {
+        static IApp? app;
+
+        public static void Main(string[] args)
+        {
+            app = new MeadowApp();
+
+            Thread.Sleep(Timeout.Infinite);
+        }
+    }
+}

Source/Meadow.Foundation.Peripherals/Sensors.Atmospheric.Sgp40/Samples/Sgp40_Sample/Sgp40_Sample.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Meadow.Sdk/1.1.0">
+  <PropertyGroup>
+    <RepositoryUrl>https://github.com/WildernessLabs/Meadow.Foundation</RepositoryUrl>
+    <Company>Wilderness Labs, Inc</Company>
+    <Authors>Wilderness Labs, Inc</Authors>
+    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
+    <TargetFramework>netstandard2.1</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <AssemblyName>App</AssemblyName>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <LangVersion>8.0</LangVersion>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <LangVersion>8.0</LangVersion>
+  </PropertyGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\..\..\Meadow.Core\source\Meadow.F7\Meadow.F7.csproj" />
+    <ProjectReference Include="..\..\Driver\Sensors.Atmospheric.Sgp40.csproj" />
+  </ItemGroup>
+</Project>

Source/Meadow.Foundation.sln

@@ -1046,6 +1046,14 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{494A
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Bh1900Nux_Sample", "Meadow.Foundation.Peripherals\Sensors.Atmospheric.Bh1900Nux\Samples\Bh1900Nux_Sample\Bh1900Nux_Sample.csproj", "{43DA872D-F7E2-4CD6-A5F9-3E50FFBE73B3}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Sensors.Atmospheric.Sgp40", "Sensors.Atmospheric.Sgp40", "{B98533B9-CA48-4F0D-961B-C95BD5158391}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{F2ECD777-3B3B-4EF1-B68C-E31AAADBF2B5}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Sensors.Atmospheric.Sgp40", "Meadow.Foundation.Peripherals\Sensors.Atmospheric.Sgp40\Driver\Sensors.Atmospheric.Sgp40.csproj", "{71EBC24D-5B32-4E76-ADF3-DE0017946108}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Sgp40_Sample", "Meadow.Foundation.Peripherals\Sensors.Atmospheric.Sgp40\Samples\Sgp40_Sample\Sgp40_Sample.csproj", "{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -2446,6 +2454,18 @@ Global
 		{43DA872D-F7E2-4CD6-A5F9-3E50FFBE73B3}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{43DA872D-F7E2-4CD6-A5F9-3E50FFBE73B3}.Release|Any CPU.Build.0 = Release|Any CPU
 		{43DA872D-F7E2-4CD6-A5F9-3E50FFBE73B3}.Release|Any CPU.Deploy.0 = Release|Any CPU
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108}.Release|Any CPU.Build.0 = Release|Any CPU
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108}.Release|Any CPU.Deploy.0 = Release|Any CPU
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493}.Release|Any CPU.Deploy.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -2966,6 +2986,10 @@ Global
 		{71FE0FFA-F897-4067-8687-A033B5D0BB5D} = {6E207804-A991-42DD-BE14-AB8E18940162}
 		{494AAADA-7CF7-44A4-AFB2-4AEC664151E3} = {6E207804-A991-42DD-BE14-AB8E18940162}
 		{43DA872D-F7E2-4CD6-A5F9-3E50FFBE73B3} = {494AAADA-7CF7-44A4-AFB2-4AEC664151E3}
+		{B98533B9-CA48-4F0D-961B-C95BD5158391} = {64623FCA-6086-4F0A-A59D-2BF372EA38AA}
+		{F2ECD777-3B3B-4EF1-B68C-E31AAADBF2B5} = {B98533B9-CA48-4F0D-961B-C95BD5158391}
+		{71EBC24D-5B32-4E76-ADF3-DE0017946108} = {B98533B9-CA48-4F0D-961B-C95BD5158391}
+		{1ACC6BA0-8108-4BFA-9A75-9063B5E07493} = {F2ECD777-3B3B-4EF1-B68C-E31AAADBF2B5}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {AF7CA16F-8C38-4546-87A2-5DAAF58A1520}