hpm

HPM Particle Sensor Driver for Android Things

This driver supports the Honeywell HPM particle sensor. The sensor counts both PM2.5 and PM10 sized particles present in the air.

How to use the driver

Gradle dependency

To use the hpm 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 'jpuderer.android.things.drivers:driver-hpm:0.2'
    ...
}

Sample usage

import net.jpuderer.android.things.drivers.hpm.HpmSensorDriver;

// Honeywell HPM Partical Sensor
HpmSensor mHpmSensor;

try {
    mHpmSensor = new HpmSensor(uartName);
    mHpmSensor.start();
} catch (IOException e) {
    // couldn't configure the device...
}

// Read PM2.5 and PM10 particle counts

try {
    int pm25 = mHpmSensor.readPm25();
    int pm10 = mHpmSensor.readPm10();
} catch (IOException e) {
    // error reading sensor
}

// Close the particle sensor when finished:

try {
    mHpmSensor.close();
} catch (IOException e) {
    // error closing sensor
}

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

SensorManager mSensorManager = getSystemService(Context.SENSOR_SERVICE);
SensorEventListener mListener = ...;
HpmSensorDriver mSensorDriver;

mSensorManager.registerDynamicSensorCallback(new SensorManager.DynamicSensorCallback() {
    @Override
    public void onDynamicSensorConnected(Sensor sensor) {
        if (sensor.getType() == Sensor.TYPE_DEVICE_PRIVATE_BASE && 
		(HpmSensorDriver.SENSOR_STRING_TYPE.equals(sensor.getStringType()))) {
            mSensorManager.registerListener(mListener, sensor,
                    SensorManager.SENSOR_DELAY_NORMAL);
        }
    }
});

try {
    mSensorDriver = new HpmSensorDriver(uartName);
    mSensorDriver.registerParticleSensor();
} catch (IOException e) {
    // Error configuring sensor
}

// Unregister and close the driver when finished:

mSensorManager.unregisterListener(mListener);
mSensorDriver.unregisterParticleSensor();
try {
    mSensorDriver.close();
} catch (IOException e) {
    // error closing sensor
}