Counter Activity was a class project for
Mobile & Ubiquitous Computing (CS 7470). We began the project with the aim of tracking user
activity at a kitchen counter. This was inspired by research on
Deja Vu displays
that is currently being conducted at the Aware home. While the Deja Vu displays currently use a wizard
of Oz system to detemine user activity on the counter we believe that it will eventually be possible
to automatically gather activity data
Design and development process
We went through an extensive brainstorming to decide exactly what type of sensing technology would be
best suited to our goal. Some of the technologies we considered were vision, touch sensitivity,
ultrasonic trackers and accelerometers. We eventually settled on using RFID as our primary tracking
technology since it was a cheap and robust system as well as the fact that many industries are planning
to add RFID tags on consumer products which will allow any RFID based tracking system to quickly acheive
critical mass.
Most current RFID systems involve a fixed RFID reader and require that the tagged objects be moved
across the readers field to be read. We wished to reverse that trend by attaching the RFID reader to
the users hand while tagging the various objects that they would come in contact with. By constantly
polling the RFID reader we would be able to determine which objects the user was interacting
with. We also planned to embedd RFID tags in strategic area on the kitchen counter which would enable
us to simultaneously track the position of the users hand.
After receiving an RFID reader we quickly realised that not only was the reader extremely large, but
it also had a very low range (1-3 inches). This meant that we had to investigate alternative
technologies to track the position of the users hand. Our first choice was the
HP badge 4 system since it not
only had an onboard accelerometer but also a strong ARM processor which could be used to control the
RFID reader as well as wireless capabilities which would allow the users to work without a tether. Our
next choice was to use a Nintendo power glove which used an ultrasonic tracker to determine hand
position and orientation with 6 degrees of freedom. It also had an elastic sensor which could sense if
the users hand was open or closed. We purchased a powerglove but were unable to hack the Nintendo
interface to a computer.
Eventually we a software system that could accurately sense and keep track of the various objects that
were in the RFID readers' range. We also used Wizard of Oz inputs to allow the system determine the
position and orientation of the users hand.