Meadow.Foundation.Sensors.Atmospheric.Ccs811

Ccs811
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

Code Example

Ccs811 sensor;

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

    var i2cBus = Device.CreateI2cBus(Meadow.Hardware.I2cBusSpeed.Fast);
    sensor = new Ccs811(i2cBus);

    var consumer = Ccs811.CreateObserver(
        handler: result =>
        {
            Resolver.Log.Info($"Observer triggered:");
            Resolver.Log.Info($"   new CO2: {result.New.Co2?.PartsPerMillion:N1}ppm, old: {result.Old?.Co2?.PartsPerMillion:N1}ppm.");
            Resolver.Log.Info($"   new VOC: {result.New.Voc?.PartsPerBillion:N1}ppb, old: {result.Old?.Voc?.PartsPerBillion:N1}ppb.");
        },
        filter: result =>
        {
            if (result.Old is { } old)
            {
                return (
                (result.New.Co2.Value - old.Co2.Value).Abs().PartsPerMillion > 1000 // 1000ppm
                  &&
                (result.New.Voc.Value - old.Voc.Value).Abs().PartsPerBillion > 100 // 100ppb
                );
            }
            return false;
        }
    );
    sensor.Subscribe(consumer);

    sensor.Updated += (sender, result) =>
    {
        Resolver.Log.Info($"CO2: {result.New.Co2.Value.PartsPerMillion:n1}ppm, VOC: {result.New.Voc.Value.PartsPerBillion:n1}ppb");
    };

    return Task.CompletedTask;
}

public override async Task Run()
{
    var result = await sensor.Read();
    Resolver.Log.Info("Initial Readings:");
    Resolver.Log.Info($"  CO2: {result.Co2.Value.PartsPerMillion:n1}ppm");
    Resolver.Log.Info($"  VOC: {result.Voc.Value.PartsPerBillion:n1}ppb");

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

Sample project(s) available on GitHub

Wiring Example

To wire a Ccs811 to your Meadow board, connect the following:

Ccs811	Meadow Pin
GND	GND
VCC	3V3
SCL	D08
SDA	D07

It should look like the following diagram:

Class Ccs811

Provide access to the CCS811 C02 and VOC Air Quality Sensor

Assembly: Ccs811.dll

View Source

Declaration

public class Ccs811 : PollingSensorBase<(Concentration? Co2, Concentration? Voc)>, IObservable<IChangeResult<(Concentration? Co2, Concentration? Voc)>>, ISamplingSensor<(Concentration? Co2, Concentration? Voc)>, ISensor<(Concentration? Co2, Concentration? Voc)>, ICo2Sensor, IVocSensor, ISamplingSensor<Concentration>, ISensor<Concentration>, ISensor, ISamplingSensor, II2cPeripheral

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

Implements:

Expand

System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>>, Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>, Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>, Meadow.Peripherals.Sensors.Atmospheric.ICo2Sensor, Meadow.Peripherals.Sensors.Atmospheric.IVocSensor, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Concentration>, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Concentration>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor, Meadow.Hardware.II2cPeripheral

Properties

Co2

The measured CO2 concentration

View Source

Declaration

public Concentration? Co2 { get; }

Voc

The measured VOC concentration

View Source

Declaration

public Concentration? Voc { get; }

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()

Exceptions

System.Exception
Raised if HW_ID register returns an invalid id

GetBaseline()

Get baseline value

View Source

Declaration

public ushort GetBaseline()

Returns

System.UInt16: The baseline value### SetBaseline(ushort) Set the baseline value

View Source

Declaration

public void SetBaseline(ushort value)

Parameters

Type	Name	Description
System.UInt16	value	The new baseline

GetMeasurementMode()

Get the current measurement mode

View Source

Declaration

public Ccs811.MeasurementMode GetMeasurementMode()

Returns

Meadow.Foundation.Sensors.Atmospheric.Ccs811.MeasurementMode: The measurement mode### SetMeasurementMode(MeasurementMode) Set the Measurement mode

View Source

Declaration

public void SetMeasurementMode(Ccs811.MeasurementMode mode)

Parameters

Type	Name	Description
Meadow.Foundation.Sensors.Atmospheric.Ccs811.MeasurementMode	mode	The new mode

ReadSensor()

Reads data from the sensor

View Source

Declaration

protected override Task<(Concentration? Co2, Concentration? Voc)> ReadSensor()

Returns

System.Threading.Tasks.Task<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>: The latest sensor reading### RaiseEventsAndNotify(IChangeResult<(Concentration? Co2, Concentration? Voc)>) Raise events for subscribers and notify of value changes

View Source

Declaration

protected override void RaiseEventsAndNotify(IChangeResult<(Concentration? Co2, Concentration? Voc)> changeResult)

Parameters

Type	Name	Description
Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>	changeResult	The updated sensor data

Events

VocUpdated

Event raised when the VOC concentration value changes

View Source

Declaration

public event EventHandler<ChangeResult<Concentration>> VocUpdated

Event Type

System.EventHandler<Meadow.ChangeResult<Meadow.Units.Concentration>>

Implements

• System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>>
• Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>
• Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Concentration>,System.Nullable<Meadow.Units.Concentration>>>
• Meadow.Peripherals.Sensors.Atmospheric.ICo2Sensor
• Meadow.Peripherals.Sensors.Atmospheric.IVocSensor
• Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Concentration>
• Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Concentration>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor
• Meadow.Hardware.II2cPeripheral