.. highlight:: csharp

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 <http://www.mouser.com/ds/2/239/Lite-On_LTR-329ALS-01%20DS_ver1.1-348647.pdf>`_ device from 
Lite-On, represented by the 
`IAmbientLightLtr329 <http://mbientlab.com/docs/metawear/csharp/1/interfaceMbientLab_1_1MetaWear_1_1Sensor_1_1IAmbientLightLtr329.html>`_ interface.

::

    using MbientLab.MetaWear.Sensor;

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


Configuration
-------------
The sensor has three configurable parameters, set with the module's 
`Configure <http://mbientlab.com/docs/metawear/csharp/1/interfaceMbientLab_1_1MetaWear_1_1Sensor_1_1IAmbientLightLtr329.html#a8619ff98388784c57e36e3008ef9c143>`_ 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>()))
    );