Remarks
| Mpl3115a2 | |
|---|---|
| Status |  |
| Source code | GitHub |
| Datasheet(s) | GitHub |
| NuGet package |  |
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($"Observer: Temp changed by threshold; new temp: {result.New.Temperature?.Celsius:N2}C, old: {result.Old?.Temperature?.Celsius:N2}C");
},
filter: result =>
{
//c# 8 pattern match syntax. checks for !null and assigns var.
if (result.Old?.Temperature is { } oldTemp &&
result.New.Temperature is { } newTemp)
{
return (newTemp - oldTemp).Abs().Celsius > 0.5; // returns true if > 0.5°C change.
}
return false;
}
);
sensor.Subscribe(consumer);
sensor.Updated += (sender, result) => {
Resolver.Log.Info($" 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:
Syntax
public class Mpl3115a2 : ByteCommsSensorBase<(Units.Temperature? Temperature, Pressure? Pressure)>, ISamplingSensor<(Units.Temperature? Temperature, Pressure? Pressure)>, ISamplingSensor<(Units.Temperature? Temperature, Pressure? Pressure)>, IDisposable, ITemperatureSensor, IBarometricPressureSensorConstructors
Mpl3115a2(II2cBus, Byte)
Create a new MPL3115A2 object with the default address and speed settings
Declaration
public Mpl3115a2(II2cBus i2cBus, byte address = null)Parameters
| Type | Name | Description |
|---|---|---|
| II2cBus | i2cBus | I2cBus (Maximum is 400 kHz) |
| System.Byte | address | Address of the sensor (default = 0x60) |
Properties
Pressure
The pressure, from the last reading.
Declaration
public Pressure? Pressure { get; }Property Value
| Type | Description |
|---|---|
| System.Nullable<Pressure> |
Standby
Check if the part is in standby mode or change the standby mode.
Declaration
public bool Standby { get; set; }Property Value
| Type | Description |
|---|---|
| System.Boolean |
Remarks
Changes the SBYB bit in Control register 1 to put the device to sleep or to allow measurements to be made.
Status
Get the status register from the sensor
Declaration
public byte Status { get; }Property Value
| Type | Description |
|---|---|
| System.Byte |
Temperature
The temperature, from the last reading.
Declaration
public Units.Temperature? Temperature { get; }Property Value
| Type | Description |
|---|---|
| System.Nullable<Units.Temperature> |
Methods
RaiseEventsAndNotify(IChangeResult<(Nullable<Units.Temperature> Temperature, Nullable<Pressure> Pressure)>)
Inheritance-safe way to raise events and notify observers.
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()
Update the temperature and pressure from the sensor and set the Pressure property.
Declaration
protected override Task<(Units.Temperature? Temperature, Pressure? Pressure)> ReadSensor()Returns
| Type | Description |
|---|---|
| Task<System.ValueTuple<System.Nullable<Units.Temperature>, System.Nullable<Pressure>>> |
Overrides
Reset()
Reset the sensor
Declaration
public void Reset()Events
PressureUpdated
Event raised when pressure value changes
Declaration
public event EventHandler<IChangeResult<Pressure>> PressureUpdatedEvent Type
| Type | Description |
|---|---|
| EventHandler<IChangeResult<Pressure>> |
TemperatureUpdated
Event raised when temperature value changes
Declaration
public event EventHandler<IChangeResult<Units.Temperature>> TemperatureUpdatedEvent Type
| Type | Description |
|---|---|
| EventHandler<IChangeResult<Units.Temperature>> |