Skip to main content

Meadow.Foundation.Sensors.Atmospheric.Mpl3115a2

Mpl3115a2
StatusStatus badge: working
Source codeGitHub
Datasheet(s)GitHub
NuGet packageNuGet Gallery for Meadow.Foundation.Sensors.Atmospheric.Mpl3115a2

The MPL3115A2 is a barometric pressure sensor capable of reading both temperature and temperature compensated pressure reading. This sensor includes the following features:

  • I2C digital interface
  • 24-bit ADC
  • Altitude and pressure measurements
  • Temperature sensor

Sample projects available on GitHub

Purchasing​

The MPL3115A2 is available on breakout boards and a weather shield:

Code Example​

Mpl3115a2? sensor;

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

    sensor = new Mpl3115a2(Device.CreateI2cBus());

    var consumer = Mpl3115a2.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; // returns true if > 0.5°C change.
            }
            return false;
        }
    );
    sensor.Subscribe(consumer);

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

    return Task.CompletedTask;
}

public override async Task Run()
{
    if (sensor == null) { return; }

    var conditions = await sensor.Read();
    Resolver.Log.Info($"Temperature: {conditions.Temperature?.Celsius}°C, Pressure: {conditions.Pressure?.Pascal}Pa");

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

Sample project(s) available on GitHub

Interrupt Mode​

The application below connects the MPL3115A2 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 100 milliseconds (the default for the updatePeriod).

public class MeadowApp : App<F7Micro, MeadowApp>
{
    public MeadowApp()
    {
        Console.WriteLine("MPL3115A2 Interrupt Example");
        var mpl3115a2 = new MPL3115A2(temperatureChangeNotificationThreshold: 0.1F);
        mpl3115a2.TemperatureChanged += (s, e) =>
        {
            Console.WriteLine("Temperature: " + mpl3115a2.Temperature.ToString("f2"));
        };
        mpl3115a2.PressureChanged += (s, e) =>
        {
            Console.WriteLine("Pressure: " + mpl3115a2.Pressure.ToString("f2")); 
        };
        Thread.Sleep(Timeout.Infinite);
    }
}

Polling Mode​

The following application reads the temperature and pressure every second and displays the result on the debug console:

public class MeadowApp : App<F7Micro, MeadowApp>
{
    public MeadowApp()
    {
        Console.WriteLine("MPL3115A2 Polling Example");
        var mpl3115a2 = new MPL3115A2(updateInterval: 0);
        while (true)
        {
            mpl3115a2.Update();
            Console.WriteLine("Temperature: " + mpl3115a2.Temperature.ToString("f2") + ", Pressure: " + mpl3115a2.Pressure.ToString("f2"));
            Thread.Sleep(1000);
        }
    }
}

Wiring Example​

MPL3115A2 configured for polling more data reads:

Class Mpl3115a2

Driver for the MPL3115A2 pressure and humidity sensor

Assembly: Mpl3115a2.dll​
View Source​
Declaration
public class Mpl3115a2 : ByteCommsSensorBase<(Temperature? Temperature, Pressure? Pressure)>, IObservable<IChangeResult<(Temperature? Temperature, Pressure? Pressure)>>, ISamplingSensor<(Temperature? Temperature, Pressure? Pressure)>, ISensor<(Temperature? Temperature, Pressure? Pressure)>, IDisposable, ITemperatureSensor, ISamplingSensor<Temperature>, ISensor<Temperature>, IBarometricPressureSensor, ISamplingSensor<Pressure>, ISensor<Pressure>, ISensor, ISamplingSensor, II2cPeripheral

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>>>, System.IDisposable, 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.II2cPeripheral

Properties​

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; }

Standby​

Check if the part is in standby mode or change the standby mode.

View Source​
Declaration
public bool Standby { get; set; }

Status​

Get the status register from the sensor

View Source​
Declaration
public byte Status { get; }

DefaultI2cAddress​

The default I2C address for the peripheral

View Source​
Declaration
public byte DefaultI2cAddress { get; }

Methods​

ReadSensor()​

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

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>>>

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

Inheritance-safe way to raise events and notify observers.

View Source​
Declaration
protected override void RaiseEventsAndNotify(IChangeResult<(Temperature? Temperature, Pressure? Pressure)> changeResult)
Parameters​
TypeName
Meadow.IChangeResult<System.ValueTuple<System.Nullable<Meadow.Units.Temperature>,System.Nullable<Meadow.Units.Pressure>>>changeResult

Reset()​

Reset the sensor

View Source​
Declaration
public void Reset()

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>>>
  • System.IDisposable
  • 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.II2cPeripheral