Remarks

Bmp180
Status Status badge: working
Source code GitHub
Datasheet(s) GitHub
NuGet package NuGet Gallery for Meadow.Foundation.Sensors.Atmospheric.Bmp180

The BMP180 is a high-precision, low-power barometric pressure sensor. The BMP180 offers a measuring range of 300 to 1100 hPa with an absolute accuracy of down to 0.03 hPa. It's based on piezo-resistive technology for EMC robustness, high accuracy and linearity as well as long term stability. It is designed to be connected directly to a micro-controller via the I2C bus.

Code Example

Bmp180 sensor;

public override Task Initialize()
{
    Console.WriteLine("Initializing...");

    sensor = new Bmp180(Device.CreateI2cBus());

    var consumer = Bmp180.CreateObserver(
        handler: result =>
        {
            Console.WriteLine($"Observer: Temp changed by threshold; new temp: {result.New.Temperature?.Celsius:N2}C, old: {result.Old?.Temperature?.Celsius:N2}C");
        },
        filter: result =>
        {
            //c# 8 pattern match syntax. checks for !null and assigns var.
            if (result.Old is { } old)
            {
                return (
                (result.New.Temperature.Value - old.Temperature.Value).Abs().Celsius > 0.5);
            }
            return false;
        }
    );
    sensor.Subscribe(consumer);

    sensor.Updated += (sender, result) =>
    {
        Console.WriteLine($"  Temperature: {result.New.Temperature?.Celsius:N2}C");
        Console.WriteLine($"  Pressure: {result.New.Pressure?.Bar:N2}bar");
    };

    return Task.CompletedTask;
}

public override async Task Run()
{
    var conditions = await sensor.Read();
    Console.WriteLine($"Temperature: {conditions.Temperature?.Celsius}°C, Pressure: {conditions.Pressure?.Pascal}Pa");

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

Sample project(s) available on GitHub

Wiring Example

To wire a BMP180 to your Meadow board, connect the following:

BMP180 Meadow Pin
GND GND
SCL D08 (SCL)
SDA D07 (SDA)
VCC 3V3

It should look like the following diagram:

Characteristic Locus
Inheritance System.Object ObservableBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>> SensorBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>> SamplingSensorBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>> ByteCommsSensorBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>> > Bmp180
Implements IDisposable ITemperatureSensor IBarometricPressureSensor
Inherited Members ByteCommsSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Peripheral ByteCommsSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.ReadBuffer ByteCommsSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.WriteBuffer ByteCommsSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Init(Int32, Int32) ByteCommsSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Dispose(Boolean) ByteCommsSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Dispose() SamplingSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.StartUpdating(Nullable<TimeSpan>) SamplingSensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.StopUpdating() SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Updated SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.samplingLock SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.SamplingTokenSource SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Conditions SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.IsSampling SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.UpdateInterval SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.ReadSensor() SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.RaiseEventsAndNotify(IChangeResult<>) SensorBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.Read() ObservableBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.observers ObservableBase<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>.NotifyObservers(IChangeResult<>) Meadow.Foundation.ObservableBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>>.Subscribe(IObserver<>) Meadow.Foundation.ObservableBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>>.CreateObserver(Action<>, System.Nullable<Predicate<IChangeResult<UNIT>>>)
Namespace Meadow.Foundation.Sensors.Atmospheric
Assembly Bmp180.dll

Syntax

public class Bmp180 : ByteCommsSensorBase<(Units.Temperature? Temperature, Pressure? Pressure)>, IDisposable, ITemperatureSensor, IBarometricPressureSensor

Constructors

Bmp180(II2cBus, Byte, Bmp180.DeviceMode)

Provide a mechanism for reading the temperature and humidity from a Bmp085 temperature / humidity sensor.

Declaration
public Bmp180(II2cBus i2cBus, byte address = null, Bmp180.DeviceMode deviceMode = default(Bmp180.DeviceMode))

Parameters

Type Name Description
II2cBus i2cBus
System.Byte address
Bmp180.DeviceMode deviceMode

Fields

DEFAULT_SPEED

Declaration
public const int DEFAULT_SPEED = null

Field Value

Type Description
System.Int32

Properties

Pressure

Last value read from the Pressure sensor.

Declaration
public Pressure? Pressure { get; }

Property Value

Type Description
System.Nullable<Pressure>

Temperature

Last value read from the Pressure sensor.

Declaration
public Units.Temperature? Temperature { get; }

Property Value

Type Description
System.Nullable<Units.Temperature>

Methods

RaiseEventsAndNotify(IChangeResult<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>)

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

Parameters

Type Name Description
IChangeResult<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>> changeResult

ReadSensor()

Calculates the compensated pressure and temperature.

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

Returns

Type Description
Task<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>>

Overrides

Meadow.Foundation.SensorBase<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>>.ReadSensor()

Events

PressureUpdated

Declaration
public event EventHandler<IChangeResult<Pressure>> PressureUpdated

Event Type

Type Description
EventHandler<IChangeResult<Pressure>>

TemperatureUpdated

Declaration
public event EventHandler<IChangeResult<Units.Temperature>> TemperatureUpdated

Event Type

Type Description
EventHandler<IChangeResult<Units.Temperature>>