Remarks

Bmp180
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

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 MeadowApp()
{
    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");
    };

    ReadConditions().Wait();

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

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

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<ValueTuple<Nullable<Units.Temperature>, Nullable<Pressure>>>) 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<ValueTuple<Nullable<Units.Temperature>, Nullable<Pressure>>>) 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<Meadow.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>>