Remarks

Bmp180
Status
Source code	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

public class MeadowApp : App<F7Micro, MeadowApp>
{
    Bmp180 bmp180;

    public MeadowApp()
    {
        Console.WriteLine("Initializing...");

        // configure our BME280 on the I2C Bus
        var i2c = Device.CreateI2cBus();
        bmp180 = new Bmp180(i2c);

        // Example that uses an IObersvable subscription to only be notified
        // when the temperature changes by at least a degree, and humidty by 5%.
        // (blowing hot breath on the sensor should trigger)
        bmp180.Subscribe(new FilterableObserver<AtmosphericConditionChangeResult, AtmosphericConditions>(
            h => {
                Console.WriteLine($"Temp and pressure changed by threshold; new temp: {h.New.Temperature}, old: {h.Old.Temperature}");
            },
            e => {
                return (
                    (Math.Abs(e.Delta.Temperature) > 1)
                    &&
                    (Math.Abs(e.Delta.Pressure) > 5)
                    );
            }
            ));

        // classical .NET events can also be used:
        bmp180.Updated += (object sender, AtmosphericConditionChangeResult e) => {
            Console.WriteLine($"Temperature: {e.New.Temperature}°C, Pressure: {e.New.Pressure}hPa");
        };

        // get an initial reading
        ReadConditions().Wait();

        // start updating continuously
        bmp180.StartUpdating();
    }

    protected async Task ReadConditions()
    {
        var conditions = await bmp180.Read();
        Console.WriteLine($"Temperature: {conditions.Temperature}°C, Pressure: {conditions.Pressure}hPa");
    }
}

Sample projects 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 > Bmp180
Implements	IAtmosphericSensor IBarometricPressureSensor ITemperatureSensor
Namespace	Meadow.Foundation.Sensors.Atmospheric
Assembly	Bmp180.dll

Syntax

public class Bmp180 : FilterableChangeObservableBase<AtmosphericConditionChangeResult, AtmosphericConditions>, IAtmosphericSensor, IBarometricPressureSensor, ITemperatureSensor

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 = 119, Bmp180.DeviceMode deviceMode = Bmp180.DeviceMode.Standard)

Parameters

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

Properties

Conditions

The AtmosphericConditions from the last reading.

Declaration

public AtmosphericConditions Conditions { get; protected set; }

Property Value

Type	Description
AtmosphericConditions

DEFAULT_SPEED

Declaration

public static int DEFAULT_SPEED { get; }

Property Value

Type	Description
System.Int32

IsSampling

Gets a value indicating whether the analog input port is currently sampling the ADC. Call StartSampling() to spin up the sampling process.

Declaration

public bool IsSampling { get; protected set; }

Property Value

Type	Description
System.Boolean	true if sampling; otherwise, false.

Pressure

Pressure

Declaration

public float Pressure { get; }

Property Value

Type	Description
System.Single

Temperature

The temperature, in degrees celsius (°C), from the last reading.

Declaration

public float Temperature { get; }

Property Value

Type	Description
System.Single

Methods

Dispose()

Declaration

public void Dispose()

RaiseChangedAndNotify(AtmosphericConditionChangeResult)

Declaration

protected void RaiseChangedAndNotify(AtmosphericConditionChangeResult changeResult)

Parameters

Type	Name	Description
AtmosphericConditionChangeResult	changeResult

Read()

Convenience method to get the current sensor readings. For frequent reads, use StartSampling() and StopSampling() in conjunction with the SampleBuffer.

Declaration

public Task<AtmosphericConditions> Read()

Returns

Type	Description
System.Threading.Tasks.Task<AtmosphericConditions>

StartUpdating(Int32)

Declaration

public void StartUpdating(int standbyDuration = 1000)

Parameters

Type	Name	Description
System.Int32	standbyDuration

StopUpdating()

Stops sampling the temperature.

Declaration

public void StopUpdating()

Events

Updated

Declaration

public event EventHandler<AtmosphericConditionChangeResult> Updated

Event Type

Type	Description
System.EventHandler<AtmosphericConditionChangeResult>