accelerometer jitter

Steve Mosher steve at
Sun Sep 21 04:54:53 CEST 2008

  since low cost accelerometers are somewhat noisy, I'd suspect that first.

Not sure what kind of filter you should use. There should be some guys 
On the list who can chime in better than I can.

Joel Newkirk wrote:
> I wrote a short shell script to repeatedly take the raw output from one of
> the accelerometers (/sys/devices/platform/spi_s3c24xx_gpio.1/spi0.1/dump)
> and massage the data to output X,Y,and Z-axis readings in decimal, -128 to
> 128.
> With my Freerunner sitting flat, face up, on the concrete slab of my house,
> the 'Z' reading (positive Z is toward the back of the handset, BTW)
> fluctuates between 51 and 56. (X and Y range from -1 to 2)  That's a
> variance of +/- 5%, and I'm fairly confident gravity isn't fluctuating
> significantly... ;)
> Is that to be expected, is my Freerunner defective, or am I doing something
> wrong? 
> I'm trying to develop a simple tool that will determine 'down' based on
> output from the accelerometer, and indicate deviations from various
> 90-degree orientations - will I need to massage the data further to ignore
> variations, should I be averaging several readings, or what?
> j
> _______________________________________________
> Openmoko community mailing list
> community at

More information about the community mailing list