Meadow.Foundation.Sensors.Atmospheric.MPL115A2

Mpl115a2
Status
Source code	GitHub
Datasheet(s)	GitHub
NuGet package

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

Code Example

Mpl115a2 sensor;

public override Task Initialize()
{
    Console.WriteLine("Initializing...");

    sensor = new Mpl115a2(Device.CreateI2cBus());

    var consumer = Mpl115a2.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?.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) => {
        Console.WriteLine($"  Temperature: {result.New.Temperature?.Celsius:N2}C");
        Console.WriteLine($"  Pressure: {result.New.Pressure?.Bar:N2}Bar");
    };

    return Task.CompletedTask;
}

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

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

Sample project(s) available on GitHub

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.