Web Browser?

steve steve at openmoko.com
Thu Apr 10 01:16:12 CEST 2008

The accelerometers measure gforce. They measure this force at a certain
frequency ( the spec is out there) as with all accelerometers there is a
measurement error and a drift. the Phone has two 3 axis accelerometers, and
simple physics tells you if you have Xdotdot, Ydotdot, and Zdotdot, you
can integrate over time and get velocity in each axis and integrate again
to get position. So in theory you can compute the entire 6DOF relative
geometry of the system (x,y,z, psi, theta,phi)

However, the noise in the signal and your integration step will limit
your accuracy. So, its very application specific.

For filtering there are many choices. If you know the underlying dynamic
model then a Kalman filter might be a
good choice. If you google or wikipedia on kalman filter and accelerometer
you should find stuff. code even.

The neat trick is combining GPS data with accelerometer data.

-----Original Message-----
From: community-bounces at lists.openmoko.org
[mailto:community-bounces at lists.openmoko.org] On Behalf Of simarillion
Sent: Wednesday, April 09, 2008 2:29 AM
To: community at lists.openmoko.org
Subject: Re: Web Browser?

Am Mittwoch 09 April 2008 10:08:10 schrieb Ricky Fitz:
> Probably use the accelerometers for this? If phone bends over a few
> degrees, scroll down or up... ?

I think this is a great and innovative idea.

Does somebody know which resolution can be achieved with those acceleration 
sensors (single degrees, 10 degrees)? And is really a 3d position detection 
possible or are there any technical constraints.

Best regards,

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