Meadow.Foundation.Sensors.Atmospheric.Bme68x 1.3.2.3-beta

Meadow.Foundation.Sensors.Atmospheric.Bme68x

Bosch BME68x SPI / I2C humidity, barometric pressure, ambient temperature and gas (VOC) sensor

The Bme68x library is designed for the Wilderness Labs Meadow .NET IoT platform and is part of Meadow.Foundation

The Meadow.Foundation peripherals library is an open-source repository of drivers and libraries that streamline and simplify adding hardware to your C# .NET Meadow IoT application.

For more information on developing for Meadow, visit developer.wildernesslabs.co, to view all Wilderness Labs open-source projects, including samples, visit github.com/wildernesslabs

Usage

Bme680? sensor;

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

    //CreateSpiSensor();
    CreateI2CSensor();

    //uncomment to enable on sensor heater for gas readings
    //EnableGasHeater();

    var consumer = Bme680.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.Old?.Humidity is { } oldHumidity &&
                result.New.Temperature is { } newTemp &&
                result.New.Humidity is { } newHumidity)
            {
                return ((newTemp - oldTemp).Abs().Celsius > 0.5 &&
                        (newHumidity - oldHumidity).Percent > 0.05);
            }
            return false;
        }
    );

    sensor?.Subscribe(consumer);

    if (sensor != null)
    {
        sensor.Updated += (sender, result) =>
        {
            Resolver.Log.Info($"  Temperature: {result.New.Temperature?.Celsius:N2}C");
            Resolver.Log.Info($"  Relative Humidity: {result.New.Humidity:N2}%");
            Resolver.Log.Info($"  Pressure: {result.New.Pressure?.Millibar:N2}mbar ({result.New.Pressure?.Pascal:N2}Pa)");
            if (sensor.GasConversionIsEnabled)
            {
                Resolver.Log.Info($"  Gas Resistance: {result.New.GasResistance:N0}Ohms");
            }
        };
    }

    sensor?.StartUpdating(TimeSpan.FromSeconds(2));

    ReadConditions().Wait();

    return base.Initialize();
}

void EnableGasHeater()
{
    if (sensor != null)
    {
        sensor.GasConversionIsEnabled = true;
        sensor.HeaterIsEnabled = true;
        sensor.ConfigureHeatingProfile(Bme688.HeaterProfileType.Profile1, new Meadow.Units.Temperature(300), TimeSpan.FromMilliseconds(100), new Meadow.Units.Temperature(22));
        sensor.HeaterProfile = Bme688.HeaterProfileType.Profile1;
    }
}

void CreateSpiSensor()
{
    Resolver.Log.Info("Create BME680 sensor with SPI...");

    var spiBus = Device.CreateSpiBus();
    sensor = new Bme680(spiBus, Device.CreateDigitalOutputPort(Device.Pins.D14));
}

void CreateI2CSensor()
{
    Resolver.Log.Info("Create BME680 sensor with I2C...");

    var i2c = Device.CreateI2cBus();
    sensor = new Bme680(i2c, (byte)Bme688.Addresses.Address_0x76);
}

async Task ReadConditions()
{
    if (sensor == null) { return; }

    var (Temperature, Humidity, Pressure, Resistance) = await sensor.Read();

    Resolver.Log.Info("Initial Readings:");
    Resolver.Log.Info($"  Temperature: {Temperature?.Celsius:N2}C");
    Resolver.Log.Info($"  Pressure: {Pressure?.Hectopascal:N2}hPa");
    Resolver.Log.Info($"  Relative Humidity: {Humidity?.Percent:N2}%");
    Resolver.Log.Info($"  Gas Resistance: {Resistance?.Ohms:N0}Ohms");
}