Bluetooth Tracer Project

Project aims

To record some real-life computer traces of how long people (and thus their devices) spend with other people. This study has a particular focus upon the time people spend on public transport.

You will need a Bluetooth enabled phone (or other device e.g. PDA) that can run Java applications. Sony Ericsson phones are well suited (tested on K750, D750, W800, K600, K608, V600), Nokia should also work (tested on 6230i, 6630).

Anyone may participate, you only have to run a program on your phone for 2 weeks then send the text files that it creates to me.

Technical requirements

Features that your phone/PDA needs in order to participate (note: most Windows Mobile devices are not compatible):

• A Java Microedition VM (virtual machine)
• Bluetooth capability
• CLDC 1.0 (JSR 30) - A framework for Java ME
• MIDP 2.0 (JSR 118)
• JSR 82 - Bluetooth/OBEX Profile
• JSR 75 - PDA Profile
• Ability to minimise/hide MIDlets, otherwise you won't be able to do anything else!
• A memory card to store the data trace files, most phones have small versions as standard.

Basically, if you have a relatively modern phone (under a few years old), it should have Bluetooth and all the Java software required. If any of the features are not present, an error will be displayed, and the application will not run. It can just be safely deleted.

Privacy issues

Obviously, this type of study raises many privacy issues for participants. The information collected is purely the numerical Bluetooth address of any devices around you, and the time that measurement was taken. The "friendly name", that may include names/phone models/etc., is not recorded. All information about the colocations is stored on your phone and will not be available to me until you decide to send me the output file. Information about who you phone/text is not collected and no charges will be levied upon you. Before any information is processed or used in anyway, it will be anonymised to remove any trace of unique identifiers or personal information.

In short, the information you are divulging by participating is: the times your mobile phone/PDA can detect another Bluetooth device.

Download

(If you have read the privacy issues) You will need to download the following files:

  [Tracer3.jar] - The program: MIDlet archive
  [README] - Information about the usage of this program
  [Tracer3.jad] - MIDlet description file

Important: You should set the permissions on the java program to: "Allow read and write data", so it can output the data.

The code will be released under the GNU GPL when the study has completed, and is available on request.

Most phones/PDAs will be able to install this program just by transferring the .jad file to the device (via USB/Bluetooth/IR). However, some will need to either use their particular synchronisation program (Nokia PC Suite, Sony Ericsson PC Suite, WindowsMobile ActiveSync) or have to download the files manually over an Internet connection.

Completing the study

Once the application has been collecting data for enough time (at least 2 weeks), please send the dump of all the colocation to me. This is achieved by selecting the "Dump" option from the application's menu. If it asks where you would like the file stored, it is probably best to avoid internal phone memory, as that is often restricted; so choose 'E:/' or the equivalent for your phone.

The output file will be called tracer-<date>.txt and is a plain text file listing all the colocations. Please email this file to me, taking any necessary privacy precautions you want (such as PGP). It will all be stored encrypted, until it is anonymised and analysed. If you would like information about your traces just ask, and once they are collected they will be made available to you.

Possible problems / FAQ

Some possible problems that may occur while running this application (please contact me about any other problems at l.mcnamara {at} cs.ucl.ac.uk):

• How do you install the application?

Most phones should just allow you to send the .jar file over Bluetooth/IR, and it will install automatically. Otherwise, you may have to download special software from your phone manufacturers website (see above).



• The program isn't running after I turned my phone off.

The Tracer program will not always start itself up after the phone has been powered down. When you turn your phone back on, please remember to check the application is running. If it asks whether it can automatically start, say yes, then you don't have to remember to restart it.



• You are unable to perform a different task while running the application.

Unfortunately, some older phones (that have Java and Bluetooth) are unable to run a Java MIDlet in the background. This means you can only either run the application and you can't use the screen and buttons for anything else, or you can't run it.



• Your device battery time does not last as long.

Due to the regular (every 5 minutes) Bluetooth scans, your device will consume slightly more power.



• Error: "Unable to write to filesystem"

You need to give the MIDlet permission to write to files. This will be an option on your phone that you may set for the Tracer program. On most phones this will be the Application Access option of the MIDlet.



• It repeatedly asks if it is able to read/write the filesystem.

Some older phones will ask per read/write and although annoying, does not indicate a problem.



• Output file is not dumped.

Does the application have the permissions to read and modify your files?



• Error: "Attempting KNIEXT global reference with invalid handle data"

Obscure bug in Nokia Bluetooth stack, caused by waiting too long for user input. A quick reset will solve this problem.