Meadow.Foundation.Sensors.Light.Si1145

Si1145
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

The SI1145 is a low power infrared, ultraviolet and ambient light sensor with an I2C interface.

• Ultraviolet / Infrared / ambient light sensor
• Proximity sensor
• Independent LED drivers
• I2C interface up to 3.4 MBps

Sample projects available on GitHub

Purchasing

• SI1145 from Adafruit

The following application reads the sensor output Infrared, Ultraviolet and Visibility once per second and outputs the result on the output console:

Code Example

Si1145 sensor;

public override Task Initialize()
{
    Resolver.Log.Info("Initialize...");

    sensor = new Si1145(Device.CreateI2cBus());

    // Example that uses an IObservable subscription to only be notified when the filter is satisfied
    var consumer = Si1145.CreateObserver(
        handler: result => Resolver.Log.Info($"Observer: filter satisfied: {result.New.VisibleLight?.Lux:N2}Lux, old: {result.Old?.VisibleLight?.Lux:N2}Lux"),

        // only notify if the visible light changes by 100 lux (put your hand over the sensor to trigger)
        filter: result =>
        {
            if (result.Old is { } old)
            {
                // returns true if > 100lux change
                return ((result.New.VisibleLight.Value - old.VisibleLight.Value).Abs().Lux > 100);
            }
            return false;
        });

    sensor.Subscribe(consumer);

    // classical .NET events can also be used:
    sensor.Updated += (sender, result) =>
    {
        Resolver.Log.Info($" Visible Light: {result.New.VisibleLight?.Lux:N2}Lux");
        Resolver.Log.Info($" Infrared Light: {result.New.Infrared?.Lux:N2}Lux");
        Resolver.Log.Info($" UV Index: {result.New.UltravioletIndex:N2}Lux");
    };

    return Task.CompletedTask;
}

public override async Task Run()
{
    var (VisibleLight, UltravioletIndex, Infrared) = await sensor.Read();

    Resolver.Log.Info("Initial Readings:");
    Resolver.Log.Info($" Visible Light: {VisibleLight?.Lux:N2}Lux");
    Resolver.Log.Info($" Infrared Light: {Infrared?.Lux:N2}Lux");
    Resolver.Log.Info($" UV Index: {UltravioletIndex:N2}Lux");

    sensor.StartUpdating(TimeSpan.FromSeconds(1));
}

Sample project(s) available on GitHub

Wiring Example

Class Si1145

Represents a SiLabs Proximity, UV, and ambient light sensor

Assembly: Si1145.dll

View Source

Declaration

public class Si1145 : ByteCommsSensorBase<(Illuminance? VisibleLight, double? UltravioletIndex, Illuminance? Infrared)>, IObservable<IChangeResult<(Illuminance? VisibleLight, double? UltravioletIndex, Illuminance? Infrared)>>, ISamplingSensor<(Illuminance? VisibleLight, double? UltravioletIndex, Illuminance? Infrared)>, ISensor<(Illuminance? VisibleLight, double? UltravioletIndex, Illuminance? Infrared)>, ISensor, ISamplingSensor, IDisposable, II2cPeripheral

Inheritance: System.Object -> Meadow.Foundation.ObservableBase<UNIT>

Implements:
System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>>, Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>, Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor, System.IDisposable, Meadow.Hardware.II2cPeripheral

Properties

DefaultI2cAddress

The default I2C address for the peripheral

View Source

Declaration

public byte DefaultI2cAddress { get; }

Methods

ReadSensor()

Read data from the sensor

View Source

Declaration

protected override Task<(Illuminance? VisibleLight, double? UltravioletIndex, Illuminance? Infrared)> ReadSensor()

Returns

System.Threading.Tasks.Task<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>: Returns visible, ultraviolet index and infrared data

Implements

• System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>>
• Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>
• Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Illuminance>,System.Nullable<System.Double>,System.Nullable<Meadow.Units.Illuminance>>>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor
• System.IDisposable
• Meadow.Hardware.II2cPeripheral