Accelerometer wiki page erroneous axes ?

[Rui Miguel Silva Seabra]

On Wed, Apr 08, 2009 at 06:10:03PM +0200, rixed at happyleptic.org wrote:
> -[ Wed, Apr 08, 2009 at 04:26:02PM +0200, giacomo giotti mariani ]----
> > If you accelerate upwards your phone (with the screen pointing up) with
> > an acceleration a  you see a greater acceleration a_tot (along the z
> > direction) that is the sum of gravity acceleration g and your imposed
> > acceleration a (a_tot=a+g).
> 
> Well, some confusion here.
> 
> OK, let's imagine a _perfect_ accelerometer.
> This device would report only acceleration. So, when the phone lies on the
> table, it would report 0 (neglecting the rotation of earth here :-)).

It does report zero (well, in the vicinity of zero), you just have to
calculate it's difference towards the gravity vector (which is in the
vicinity of zero).

Rui

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