Meadow.Foundation.Sensors.Light.AnalogLightSensor

AnalogLightSensor
Status
Source code	GitHub
NuGet package

Code Example

AnalogLightSensor analogLightSensor;

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

    // configure our AnalogLightSensor sensor
    analogLightSensor = new AnalogLightSensor(
        analogPin: Device.Pins.A03);

    //==== IObservable Pattern with an optional notification filter.
    var consumer = AnalogLightSensor.CreateObserver(
        handler: result => Resolver.Log.Info($"Observer filter satisfied: {result.New.Lux:N2} lux, old: {result.Old.Value.Lux:N2} lux"),

        // only notify if the change is greater than 0.5
        filter: result =>
        {
            if (result.Old is { } old)
            {
                return (result.New - old).Abs().Lux > 0.5; // returns true if > 0.5  change.
            }
            return false;
        }
        // if you want to always get notified, pass null for the filter:
        //filter: null
    );
    analogLightSensor.Subscribe(consumer);

    // classical .NET events can also be used:
    analogLightSensor.IlluminanceUpdated += (sender, result) =>
        Resolver.Log.Info($"Lux changed: {result.New.Lux:N2} lux, old: {result.Old?.Lux:N2} lux");

    //==== One-off reading use case/pattern
    ReadIlluminance().Wait();

    // Spin up the sampling thread so that events are raised and IObservable notifications are sent.
    analogLightSensor.StartUpdating(TimeSpan.FromMilliseconds(1000));

    return Task.CompletedTask;
}

protected async Task ReadIlluminance()
{
    var illuminance = await analogLightSensor.Read();
    Resolver.Log.Info($"Initial lux: {illuminance.Lux:N2} lux");
}

Sample project(s) available on GitHub

Class AnalogLightSensor

Represents an analog light sensor

Assembly: Meadow.Foundation.dll

View Source

Declaration

public class AnalogLightSensor : SamplingSensorBase<Illuminance>, IObservable<IChangeResult<Illuminance>>, ILightSensor, ISamplingSensor<Illuminance>, ISensor<Illuminance>, ISensor, ISamplingSensor, IDisposable

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

Implements:
System.IObservable<Meadow.IChangeResult<Meadow.Units.Illuminance>>, Meadow.Peripherals.Sensors.Light.ILightSensor, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Illuminance>, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Illuminance>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor, System.IDisposable

Properties

AnalogInputPort

Analog port connected to sensor

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Declaration

protected IAnalogInputPort AnalogInputPort { get; }

LuminanceCalibration

Illuminance sensor calibration

View Source

Declaration

public AnalogLightSensor.Calibration LuminanceCalibration { get; protected set; }

Illuminance

Current illuminance value read by sensor

View Source

Declaration

public Illuminance? Illuminance { get; }

IsDisposed

Is the object disposed

View Source

Declaration

public bool IsDisposed { get; }

Methods

ReadSensor()

Convenience method to get the current luminance. For frequent reads, use StartSampling() and StopSampling() in conjunction with the SampleBuffer.

View Source

Declaration

protected override Task<Illuminance> ReadSensor()

Returns

System.Threading.Tasks.Task<Meadow.Units.Illuminance>

StartUpdating(TimeSpan?)

Starts continuously sampling the sensor.

This method also starts raising Changed events and IObservable subscribers getting notified. Use the readIntervalDuration parameter to specify how often events and notifications are raised/sent.

View Source

Declaration

public override void StartUpdating(TimeSpan? updateInterval)

Parameters

Type	Name	Description
System.Nullable<System.TimeSpan>	updateInterval	A TimeSpan that specifies how long to

 wait between readings. This value influences how often `*Updated`
 events are raised and `IObservable` consumers are notified.
 The default is 5 seconds. |

StopUpdating()

Stops sampling the temperature.

View Source

Declaration

public override void StopUpdating()

VoltageToLuminance(Voltage)

Converts a voltage value to a level in centimeters, based on the current calibration values.

View Source

Declaration

protected Illuminance VoltageToLuminance(Voltage voltage)

Returns

Meadow.Units.Illuminance

Parameters

Type	Name
Meadow.Units.Voltage	voltage

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

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Declaration

public void Dispose()

Dispose(bool)

Dispose of the object

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Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	Is disposing

Implements

• System.IObservable<Meadow.IChangeResult<Meadow.Units.Illuminance>>
• Meadow.Peripherals.Sensors.Light.ILightSensor
• Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Illuminance>
• Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Illuminance>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor
• System.IDisposable