What's the refresh rate/sampling rate for the sudden motion sensor?

I like using my macbook pro's sudden motion sensors as an accelerometer for small at-home experiments. There are applications such as Seismac that already let you do this.

I'm now writing one myself for my own purposes, but I couldn't find the sampling rate/refresh rate for the motion sensors. This information is critical if you need to reconstruct the 3D path accurately. Does anyone know where I can find this information?

Solution 1:

The refresh rate of the sudden motion sensor is variable.

The supported bandwith depends on the hardware used; so you have to do some more research on the specific motion sensor used in your model. I've searched ifixit without much success.

According to SeisMac the motion sensor used in the first Macbook Pro is the KXM-52. The specifications state the bandwidth depends on the axis:

• x, y axis: 0 to 3000 Hz
• z axis: 0 to 1500 Hz

[source: KXM-52 tech specs]

SeisMac itself only allows to set refresh rates between 10-500 Hz in its preferences.