A couple of servers are down at the moment here at work, so my usual news-site stumbling revealed this little gem of an article:
http://www.physorg.com/news104502773.html
In it, the author describes how university professors use a bluetooth interface to a Wii remote to calculate positioning of a pendulum based upon the accelerometer and IR sensor output of the Wii.
A Wii remote retails for $39.99 and includes all 3 axes of output data plus and IR sensor data you can use as a (dynamic, non-static!) reference point:
http://www.bestbuy.com/site/olspage....=1158316638167
The accelerometer that comes with the kit of parts costs $30 if you buy 1000 of them at a time and includes a single-axis sensor with a signal processor that determines the difference based upon the sensor's never-to-change initial state.
http://www.analog.com/en/prod/0%...C00.html#price
For a second, let's ignore the fact that currently there exists no bluetooth interface for our current robot controller. It is possible that in the future we will be able to interface to it in a much more intuitive and/or complex manner than we have now.
I do believe that the future holds a bit more for COTS (commercial off-the-shelf) products than anyone has realized. Would you go for the Wii for it's 3-axes + IR sensor for an extra $40 or are you happy with a generic, single-interface design that's provided for us every year? I ask this question with on-robot feedback control loops in mind rather than a human-robot interface controller.