Meadow.Foundation.Sensors.Light.Alspt19315C

Alspt19315C
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

The ALS-PT19-315C is a low cost analog ambient light sensor, consisting of phototransistor in a miniature SMD.

Code Example

Alspt19315C sensor;

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

    // configure our sensor
    sensor = new Alspt19315C(Device.Pins.A03);

    //==== IObservable Pattern with an optional notification filter
    var consumer = Alspt19315C.CreateObserver(
        handler: result => Resolver.Log.Info($"Observer filter satisfied: {result.New.Volts:N2}V, old: {result.Old?.Volts:N2}V"),

        // only notify if the change is greater than 0.5V
        filter: result =>
        {
            if (result.Old is { } old)
            {
                return (result.New - old).Abs().Volts > 0.5; // returns true if > 0.5V change.
            }
            return false;
        }
    );
    sensor.Subscribe(consumer);

    //==== Classic Events Pattern
    sensor.Updated += (sender, result) =>
    {
        Resolver.Log.Info($"Voltage Changed, new: {result.New.Volts:N2}V, old: {result.Old?.Volts:N2}V");
    };

    return Task.CompletedTask;
}

public override async Task Run()
{
    var result = await sensor.Read();
    Resolver.Log.Info($"Initial temp: {result.Volts:N2}V");

    sensor.StartUpdating(TimeSpan.FromMilliseconds(1000));
}

Sample project(s) available on GitHub

Wiring Example

The ALS-PT19C is a simple analog device requiring only three connections:

Class Alspt19315C

Represents an Alspt19315C analog light sensor

Assembly: Alspt19315C.dll

View Source

Declaration

public class Alspt19315C : SamplingSensorBase<Voltage>, IObservable<IChangeResult<Voltage>>, ISamplingSensor<Voltage>, ISensor<Voltage>, ISensor, ISamplingSensor

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

Implements:
System.IObservable<Meadow.IChangeResult<Meadow.Units.Voltage>>, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Voltage>, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Voltage>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor

Properties

Voltage

The current voltage reading of the sensor

View Source

Declaration

public Voltage Voltage { get; protected set; }

Methods

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. |

StopUpdating()

Stops sampling the sensor

View Source

Declaration

public override void StopUpdating()

ReadSensor()

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

View Source

Declaration

protected override Task<Voltage> ReadSensor()

Returns

System.Threading.Tasks.Task<Meadow.Units.Voltage>: A float value that's an average value of all the samples taken.

Implements

• System.IObservable<Meadow.IChangeResult<Meadow.Units.Voltage>>
• Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Voltage>
• Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Voltage>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor