Remarks

MPL115A2
Status	Untested
Source code	GitHub
NuGet package	Not published

The MPL115A2 is a low cost device for reading barometric pressure.

• I2C digital interface (address: 0x60)
• Resolution: 1.5 hPa
• Range: 100-1150 hPa up to 10Km

Sample projects available on GitHub

Purchasing

The MPL115A2 sensor is available on a breakout board from Adafruit

• Adafruit MPL115A2 Breakout Board

The application below connects the MPL115A2 to two interrupt handlers. These interrupt handlers (events) will display the Temperature and Pressure properties when the handlers are triggered. The sensor is checked every 500 milliseconds.

Wiring Example

Connecting the MPL115A2 to Meadow requires four connections:

In this diagram, the shutdown (SDWN) and reset (RST) pins have been left floating. Both of these pins are active low and can be tied to V_cc in normal operation.

Note that the Adafruit breakout board has 10K pull-up resistors on the SDA and SCK lines.

Characteristic	Locus
Inheritance	System.Object FilterableChangeObservableBase<AtmosphericConditionChangeResult, AtmosphericConditions> > Mpl115a2
Implements	System.IObservable<AtmosphericConditionChangeResult> IAtmosphericSensor ITemperatureSensor IBarometricPressureSensor
Inherited Members	FilterableChangeObservableBase<AtmosphericConditionChangeResult, AtmosphericConditions>._observers FilterableChangeObservableBase<AtmosphericConditionChangeResult, AtmosphericConditions>.NotifyObservers(AtmosphericConditionChangeResult) FilterableChangeObservableBase<AtmosphericConditionChangeResult, AtmosphericConditions>.Subscribe(IObserver<AtmosphericConditionChangeResult>) System.Object.ToString() System.Object.Equals(System.Object) System.Object.Equals(System.Object, System.Object) System.Object.ReferenceEquals(System.Object, System.Object) System.Object.GetHashCode() System.Object.GetType() System.Object.MemberwiseClone()
Namespace	Meadow.Foundation.Sensors.Atmospheric
Assembly	MPL115A2.dll

Syntax

public class Mpl115a2 : FilterableChangeObservableBase<AtmosphericConditionChangeResult, AtmosphericConditions>, IObservable<AtmosphericConditionChangeResult>, IAtmosphericSensor, ITemperatureSensor, IBarometricPressureSensor

Constructors

Mpl115a2(II2cBus, Byte)

Create a new MPL115A2 temperature and humidity sensor object.

Declaration

public Mpl115a2(II2cBus i2cBus, byte address = 96)

Parameters

Type	Name	Description
II2cBus	i2cBus	I2CBus (default to 100 KHz).
System.Byte	address	Sensor address (default to 0x60).

Properties

Conditions

The AtmosphericConditions from the last reading.

Declaration

public AtmosphericConditions Conditions { get; protected set; }

Property Value

Type	Description
AtmosphericConditions

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

The humidity, in percent relative humidity, from the last reading..

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

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()

Update()

Update the temperature and pressure from the sensor and set the Pressure property.

Declaration

public Task Update()

Returns

Type	Description
System.Threading.Tasks.Task

Events

Updated

Declaration

public event EventHandler<AtmosphericConditionChangeResult> Updated

Event Type

Type	Description
System.EventHandler<AtmosphericConditionChangeResult>