Ambient Light Sensor

Ambient light sensors convert light intensity into a digital signal using a combination of photodiodes and analog-to-digital converters. The light sensor of choice on select boards is the LTR-329ALS device from Lite-On, represented by the IAmbientLightLtr329 interface.

using MbientLab.MetaWear.Sensor;

IAmbientLightLtr329 alsLtr329 = metawear.GetModule<IAmbientLightLtr329>();

Configuration

The sensor has three configurable parameters, set with the module’s Configure function:

Parameter	Description
Gain	Controls data range and resolution
Integration Time	Measurement time for each cycle
Measurement Rate	How frequently to update illuminance data

using MbientLab.MetaWear.Sensor.AmbientLightLtr329;

// Set the gain to 8x
// Set integration time to 250ms
// Set measurement rate to 50ms
alsLtr329.Configure(gain: Gain._8x, time: IntegrationTime._250ms, rate: MeasurementRate._50ms);

Illuminance Data

Illuminance data is categorized as an async data producer; data is interpreted as a float value and is in units of lux (lx).

await als.Illuminance.AddRouteAsync(source =>
    source.Stream(data => Console.WriteLine("illuminance = " + data.Value<float>()))
);