Bosch BME280 driver for Android Things

This driver supports BME280 environmental sensor.

It’s based on Adafruit BME280 C library and BMX280 contrib-driver for Android Things.

After observing contrib-drivers early developer preview version providing inconsistent data and not supporting forced mode,
I decided to implement my own take for this driver.

• Force mode support.
• Config once and run, with sampling presets.
• Consistent data without sudden humidity spikes or pressure dropouts.

This driver is not compatible with BMP280 sensor.
Compensation formulas are different, resulting in pressure and humidity data with a slight offset.

How to use the driver

Gradle dependency

To use the bme280 driver, simply add the line below to your project’s build.gradle,
where <version> matches the last version of the driver available on jcenter .

dependencies {
    implementation 'com.knobtviker.android.things.contrib.community.driver:bme280:<version>'
}

Sample usage

import com.knobtviker.android.things.contrib.community.driver.bme280.BME280;
// Access the environmental sensor:
BME280 bme280;
try {
    bme280 = new BME280(i2cBusName);
    // Configure driver power mode and oversampling for temperature, humidity or pressure,
    bme280.setSamplingNormal(); // Various other presets are exposed
} catch (IOException e) {
    // couldn't configure the device...
}
// Read the current data:
try {
    float temperature = bme280.readTemperature();
    float humidty = bme280.readHumidity();
    float pressure = bme280.readPressure();
} catch (IOException e) {
    // error reading temperature
}
// Close the environmental sensor when finished:
try {
    bme280.close();
} catch (IOException e) {
    // error closing sensor
}

If you need to read sensor values continuously, you can register the BME280 with the system and
listen for sensor values using the Sensor APIs:

SensorManager mSensorManager = getSystemService(Context.SENSOR_SERVICE);
SensorEventListener mListener = ...;
BME280SensorDriver mSensorDriver;
mSensorManager.registerDynamicSensorCallback(new SensorManager.DynamicSensorCallback() {
    @Override
    public void onDynamicSensorConnected(Sensor sensor) {
        if (sensor.getType() == Sensor.TYPE_AMBIENT_TEMPERATURE) {
            mSensorManager.registerListener(mListener, sensor,
                    SensorManager.SENSOR_DELAY_NORMAL);
        }
    }
});
try {
    mSensorDriver = new BME280SensorDriver(i2cBusName);
    mSensorDriver.registerTemperatureSensor();
    mSensorDriver.registerHumiditySensor();
    mSensorDriver.registerPressureSensor();
} catch (IOException e) {
    // Error configuring sensor
}
// Unregister and close the driver when finished:
mSensorManager.unregisterListener(mListener);
mSensorDriver.unregisterTemperatureSensor();
mSensorDriver.unregisterPressureSensor();
mSensorDriver.unregisterHumiditySensor();
try {
    mSensorDriver.close();
} catch (IOException e) {
    // error closing sensor
}