is our debug prototype, incorporating phone, battery, and TEA2 board, but
with the bottom of the cover cut-off to easily reach and re-position the
sensors (click the pictures to see a larger version). The connection between
phone and TEA board is also external. The TEA2 board and the phone both
use an ultra-thin Nokia Li-Polymer battery, which can supply enough power
to run both components for at least a whole day.
The TEA2 board is connected
to the phone by its FBUS connector (in this version done by a small external
cable - later versions have a connector built in the module), providing
communication between the TEA device and the mobile phone.
The small microprocessor on
the TEA2 board does the aquisition of the sensordata, the pre-processing
of that data and the classification of it by a Self-Organizing Map (pretrained,
but still slightly adaptive), as well as the communication with the phone.
The mobile phone was chosen
as a case study for several reasons. First of all, Nokia is a member of
the TEA consortium and has the know-how for accessing the phone's communication
protocol and the battery circuit. Second, the mobile phone is a typical
example of how context awareness can help improving mobile devices, since
it's ringing tends not only to disturb the user, but also the people around
the user. Third, mobile phones have already a profiles-menu, which can
be used to define the behavior for the different contexts (profiles).
This way, the TEA2 board can
distinguish various contexts related to the device itself, such as "sitting
in a pocket", "lying on the desk", "in user's hand", and can ask the phone
to switch to another profile. The profile has settings that relate to (and
are named after) these contexts.
For instance, the TEA board
will detect when the user puts his phone in his pocket, so it asks the
phone to switch to the "in pocket" profile, which -among other things-
sets the phones' behavior to ringing loudly. Later, the user puts the device
on his desk. TEA agains notices this and makes the phone switch to the
"on desk" profile, which lowers the ringing volume, since it is already
very well audible.
Phone profiles are very versatile:
they can not only change the volume of the ringing, but also the ringing
tone, whether the phone should vibrate, etc. and this for both phone calls
and messages. The user can change this behavior via the phone's menu and
alter the phone's behavior for a certain profile whatever way he/she likes