Understanding accelerometer data

Neil Jerram neiljerram at googlemail.com
Thu Oct 29 23:49:07 CET 2009

2009/10/29 Michael Tansella <michael-tansella at gmx.de>:
> If the Freerunner is not moving (x^2+y^2+z^2)^(1/2) must be g. The values of
> the freerunner are in mg so it must be 1000.
> Your values are really strange. Do the x values never change?

Not never, but they do seem reluctant to change.  For example if I
lift the end of the FR with the hole in, keeping the side-to-side axis
horizontal, I would expect the x and y values of event2 to increase
equally, and z to decrease a bit.  What I observed was as expected for
y and z, but no change in x.

> I would recommend the python script for easy testing:
> http://wiki.openmoko.org/wiki/Accelerometer_data_retrieval

It's certainly possible that I've just written my program wrong.  So
yes, I'll try that script too.


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