Meadow.Foundation.Sensors.Atmospheric.Bmp280

Bmp280
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

Code Example

Bmp280 sensor;

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

    //CreateSpiSensor();
    CreateI2CSensor();

    var consumer = Bmp280.CreateObserver(
        handler: result =>
        {
            Resolver.Log.Info($"Observer: Temp changed by threshold; new temp: {result.New.Temperature?.Celsius:N2}C, old: {result.Old?.Temperature?.Celsius:N2}C");
        },
        filter: result =>
        {
            if (result.Old?.Temperature is { } oldTemp &&
                result.New.Temperature is { } newTemp)
            {
                return (newTemp - oldTemp).Abs().Celsius > 0.5;
            }
            return false;
        }
    );
    sensor.Subscribe(consumer);

    sensor.Updated += (sender, result) =>
    {
        try
        {
            Resolver.Log.Info($"  Temperature: {result.New.Temperature?.Celsius:N2}C");
            Resolver.Log.Info($"  Pressure: {result.New.Pressure?.Millibar:N2}mbar ({result.New.Pressure?.Pascal:N2}Pa)");
        }
        catch (Exception ex)
        {
            Resolver.Log.Error(ex, "Error reading sensor");
        }
    };

    return Task.CompletedTask;
}

public override async Task Run()
{
    var conditions = await sensor.Read();
    Resolver.Log.Info("Initial Readings:");
    Resolver.Log.Info($"  Temperature: {conditions.Temperature?.Celsius:N2}C");
    Resolver.Log.Info($"  Pressure: {conditions.Pressure?.Bar:N2}hPa");

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

void CreateSpiSensor()
{
    Resolver.Log.Info("Create BME280 sensor with SPI...");

    var spi = Device.CreateSpiBus();
    sensor = new Bmp280(spi, Device.Pins.D00.CreateDigitalOutputPort());
}

void CreateI2CSensor()
{
    Resolver.Log.Info("Create BME280 sensor with I2C...");

    var i2c = Device.CreateI2cBus();
    sensor = new Bmp280(i2c, (byte)Bmx280.Addresses.Default); // SDA pulled up

}

Sample project(s) available on GitHub

Wiring Example

The BMP280 can be connected using I2C or SPI. Only 4 wires are required when using I2C:

• 3.3V
• Ground
• SDA
• SCL

Class Bmp280

BMP280 Temperature and Pressure Sensor

Assembly: Bmx280.dll

View Source

Declaration

public class Bmp280 : PollingSensorBase<(Temperature? Temperature, Pressure? Pressure)>, IObservable<IChangeResult<(Temperature? Temperature, Pressure? Pressure)>>, ISamplingSensor<(Temperature? Temperature, Pressure? Pressure)>, ISensor<(Temperature? Temperature, Pressure? Pressure)>, ITemperatureSensor, ISamplingSensor<Temperature>, ISensor<Temperature>, IBarometricPressureSensor, ISamplingSensor<Pressure>, ISensor<Pressure>, ISensor, ISamplingSensor, ISpiPeripheral, II2cPeripheral, IDisposable

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

Implements:

Expand

System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>>, Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>, Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>, Meadow.Peripherals.Sensors.ITemperatureSensor, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Temperature>, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Temperature>, Meadow.Peripherals.Sensors.Atmospheric.IBarometricPressureSensor, Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Pressure>, Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Pressure>, Meadow.Peripherals.Sensors.ISensor, Meadow.Peripherals.Sensors.ISamplingSensor, Meadow.Hardware.ISpiPeripheral, Meadow.Hardware.II2cPeripheral, System.IDisposable

Properties

IsDisposed

Is the object disposed

View Source

Declaration

public bool IsDisposed { get; }

TemperatureSampleCount

Temperature oversample count

View Source

Declaration

public Bmx280.Oversample TemperatureSampleCount { get; set; }

PressureSampleCount

Pressure oversample count

View Source

Declaration

public Bmx280.Oversample PressureSampleCount { get; set; }

Temperature

The temperature from the last reading

View Source

Declaration

public Temperature? Temperature { get; }

Pressure

The pressure from the last reading

View Source

Declaration

public Pressure? Pressure { get; }

DefaultSpiBusSpeed

The default SPI bus speed for the device

View Source

Declaration

public Frequency DefaultSpiBusSpeed { get; }

SpiBusSpeed

The SPI bus speed for the device

View Source

Declaration

public Frequency SpiBusSpeed { get; set; }

DefaultSpiBusMode

The default SPI bus mode for the device

View Source

Declaration

public SpiClockConfiguration.Mode DefaultSpiBusMode { get; }

SpiBusMode

The SPI bus mode for the device

View Source

Declaration

public SpiClockConfiguration.Mode SpiBusMode { get; set; }

DefaultI2cAddress

The default I2C address for the peripheral

View Source

Declaration

public byte DefaultI2cAddress { get; }

Fields

readBuffer

The read buffer

View Source

Declaration

protected Memory<byte> readBuffer

writeBuffer

The write buffer

View Source

Declaration

protected Memory<byte> writeBuffer

Methods

Initialize()

Initialize the sensor

View Source

Declaration

protected void Initialize()

RaiseEventsAndNotify(IChangeResult<(Temperature? Temperature, Pressure? Pressure)>)

Raise events for subscribers and notify of value changes

View Source

Declaration

protected override void RaiseEventsAndNotify(IChangeResult<(Temperature? Temperature, Pressure? Pressure)> changeResult)

Parameters

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

ReadSensor()

Update the sensor information from the BME280.

View Source

Declaration

protected override Task<(Temperature? Temperature, Pressure? Pressure)> ReadSensor()

Returns

System.Threading.Tasks.Task<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>

Reset()

Reset the sensor.

View Source

Declaration

public void Reset()

GetChipID()

Get the chip ID

View Source

Declaration

public byte GetChipID()

Returns

System.Byte: The ID as a byte### StartUpdating(TimeSpan?) Start updating

View Source

Declaration

public override void StartUpdating(TimeSpan? updateInterval = null)

Parameters

Type	Name	Description
System.Nullable<System.TimeSpan>	updateInterval	The update inverval

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

View Source

Declaration

public void Dispose()

Dispose(bool)

Dispose of the object

View Source

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing	Is disposing

Implements

• System.IObservable<Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>>
• Meadow.Peripherals.Sensors.ISamplingSensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>
• Meadow.Peripherals.Sensors.ISensor<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>
• Meadow.Peripherals.Sensors.ITemperatureSensor
• Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Temperature>
• Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Temperature>
• Meadow.Peripherals.Sensors.Atmospheric.IBarometricPressureSensor
• Meadow.Peripherals.Sensors.ISamplingSensor<Meadow.Units.Pressure>
• Meadow.Peripherals.Sensors.ISensor<Meadow.Units.Pressure>
• Meadow.Peripherals.Sensors.ISensor
• Meadow.Peripherals.Sensors.ISamplingSensor
• Meadow.Hardware.ISpiPeripheral
• Meadow.Hardware.II2cPeripheral
• System.IDisposable