Data Producer

Components that create data, be it sensors or firmware features, are represented by the DataProducer interface. Manipulating the producer data, whether on the Android device or on the board itself, is expressed by a building a data route, more on that in the Data Route section.

There are three main types of data producers represented by the API:

• Asynchronous

• Forced

• Active

These three producers control the data flow slightly differently from each other, as expanded upon in the following sub sections.

Async Data Producer

Asynchronous data producers, when active, constantly measure data in the background and send it when new data is available. Once configured, call start to begin collecting data and call stop to put the producer back into standby mode.

Most sensors, such as the accelerometer, gyroscope, and magnetometer, are async data producers.

import com.mbientlab.metawear.AsyncDataProducer;

public void asycProducerCtrl(AsyncDataProducer producer) {
    // Tells producer to begin creating data
    producer.start();

    // Puts producer back to standby mode
    producer.stop();
}

Forced Data Producer

Unlike async producers, forced data producers only create data on demand when a read request is received via the read function. Asynchronous behavior can be mimicked using the Timer module to schedule periodic reads.

GPIO analog/digital, temperature, and humidity data are examples of forced data producers.

import com.mbientlab.metawear.ForcedDataProducer;

public void readForcedProducer(ForcedDataProducer producer) {
    // instructs producer to collect one data sample
    producer.read();
}

Active Data Producer

Active data producers are similar to async data producers in that they send data whenever it is ready, however, as the name implies, they are always active and are not user controlled like the other two producers. Only a few sensors are considered to be an active data producer, namely the push button switch and the power/charge status monitoring pins.