How to set up logging with CL

CL for Android can be used for logging in a variety of setups. This document gives instructions on installing CL on the subjects' devices and setting up data collection.

Installing CL for Android

At the time of writing this guide CL for Android is not published in the Android Market. That means installation has to be done after manually distributing the program binary (the APK file). The APK file can be distributed by email or made available on a web site.

Since the APK doesn't come through the Android Market, a few security features of Android need to be deactivated first.

Enable installation of apps from non market sources. This can be done by accessing the Settings app either by pressing the Menu button from the home screen and then selecting Settings. Or by selecting the Settings app from the list of available apps (please note that this second approach works mostly with tablet devices and only with very few Android phones).

After the Settings app is started you must select Applications and the check the Unknown sources option.

You can now install the APK by just tapping on it either in the email attachment section or on a web page, depending on your delivery preference.

Special note on setting up CL for Android

CL for Android can be compiled so that it doesn't appear in the user's list of installed applications. This can be helpful in studies where it is important to not remind the subjects constantly about the presence of the logger and also in studies where rather complicated settings are required and users should be prevented from accidentally changing them.

If CL for Android is compiled and installed so that it is hidden from the apps menu, then the CL starter app must be installed as well. This app can be used to bring up the CL setup screen and can be safely uninstalled after the setup is complete.

Collecting data manually

CL for Android can export the log information to a SQLite file on the SD card of the device. This can be done by pressing the Export to card button in the configuration GUI. The data can then be extracted manually from each SD card. The only limit to the amount of data logged is the device's memory capacity. That means that intervals of weeks in between exports of data are possible and don't affect the functionality of CL in any way.

Please note that when exporting the data to the SD card, CL merely takes a snapshot of the currently logged data, nothing is deleted from the device's internal memory.

Collecting data centrally

It is also possible for CL to upload logged data to a central server. For that you can either use the php upload script available here or make your own, in the language that fits you best.

At the time of writing this guide upload of data is done manually from the configuration gui by pressing the upload button (after the upload URL has been set up in CL). You can set up the upload URL in the preference screen. In one of the future versions the upload will be also automatically.