Meadow.Foundation.Sensors.Atmospheric.Bme68x 1.3.4

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");
}

How to Contribute

• Found a bug? Report an issue
• Have a feature idea or driver request? Open a new feature request
• Want to contribute code? Fork the Meadow.Foundation repository and submit a pull request against the develop branch

Need Help?

If you have questions or need assistance, please join the Wilderness Labs community on Slack.