Re: Android Sensor Coordinates

Lew <>
Fri, 01 Apr 2011 21:23:34 -0400
Peter Duniho wrote:

BGB wrote:


with the information provided thus far, once could still infer tilt via
the accelerometer...

Absolutely. The information is there. It's just not being presented as such.
If you make an assumption about the accelerometer-equipped device as a whole
not being accelerated, and further assume that it's being used on the surface
of the planet, the constant acceleration due to gravity provides a frame of
reference from which tilt can be inferred from the observed acceleration.

One can even filter the data (similar to seen in the documentation) to attempt
to determine tilt from a device that is in fact being subject to some other
(relatively constant) acceleration.

But, all that inference comes at a price, both computationally and in
precision. There's a reason that the Wiimote, in spite of having a reasonably
accurate three-axis accelerometer, derives partial tilt information from the
IR transmitter bar instead.

Thanks, you guys, for that incredibly interesting and helpful discourse.

Android's as on topic as anything else about Java in this group, AFAICS,
besides which the algorithmic insights are universal and unquestionably of use
to the Java programmer.


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