Meadow.Foundation.Sensors.Light.Max44009

Max44009
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

The Max44009 is an analog ambient light sensor.

Code Example

Max44009 sensor;

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

    sensor = new Max44009(Device.CreateI2cBus());

    // Example that uses an IObservable subscription to only be notified when the filter is satisfied
    var consumer = Max44009.CreateObserver(
        handler: result => Resolver.Log.Info($"Observer: filter satisfied: {result.New.Lux:N2}Lux, old: {result.Old?.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 - old).Abs().Lux > 100;
            }
            return false;
        });

    sensor.Subscribe(consumer);

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

    return Task.CompletedTask;
}

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

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

Sample project(s) available on GitHub

Wiring Example

To wire a Max44009 to your Meadow board, connect the following:

Max44009	Meadow Pin
SCL	D08
SDA	D07
GND	GND
VCC	3V3

It should look like the following diagram:

Class Max44009

Driver for the Max44009 light-to-digital converter

Assembly: Max44009.dll

View Source

Declaration

public class Max44009 : ByteCommsSensorBase<Illuminance>, IObservable<IChangeResult<Illuminance>>, ISamplingSensor<Illuminance>, ISensor<Illuminance>, ISensor, ISamplingSensor, IDisposable, II2cPeripheral

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

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

Initialize()

Initialize the sensor

View Source

Declaration

protected void Initialize()

ReadSensor()

Reads data from the sensor

View Source

Declaration

protected override Task<Illuminance> ReadSensor()

Returns

System.Threading.Tasks.Task<Meadow.Units.Illuminance>: The latest sensor reading

Implements

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