Mbientlab boards are equipped with flash memory that can store data if there is no connection with an Android device. While the RouteComponent directs data to the logger, the Logging interface provides the functions for controlling and configuring the logger.

import com.mbientlab.metawear.module.Logging;

final Logging logging = board.getModule(Logging.class);

Start the Logger

To start logging, call the start method. If you wish to overwrite existing entries, pass true to the method. When you are done logging, call stop.

// start logging, if log is full, no new data will be added

// start logging, if log is full, overrite existing data

// stop the logger

Note for the MMS

The MMS (MetaMotionS) board uses NAND flash memory to store data on the device itself. The NAND memory stores data in pages that are 512 entries large. When data is retrieved, it is retrieved in page sized chunks.

Before doing a full download of the log memory on the MMS, the final set of data needs to be written to the NAND flash before it can be downloaded as a page. To do this, you must call the function:


This should not be called if you are still logging data.

Downloading Data

When you are ready to retrieve the data, call downloadAsync; the method returns a Task object that will be completed when the download finishes. There are variants of downloadAsync that provide progress updates and error handing during the download.

// download log data and send 100 progress updates during the download
logging.downloadAsync(100, new Logging.LogDownloadUpdateHandler() {
    public void receivedUpdate(long nEntriesLeft, long totalEntries) {
        Log.i("MainActivity", "Progress Update = " + nEntriesLeft + "/" + totalEntries);
}).continueWithTask(new Continuation<Void, Task<Void>>() {
    public Task<Void> then(Task<Void> task) throws Exception {
        Log.i("MainActivity", "Download completed");
        return null;