1805009_en-US

FXLS896xAF AN12004 - 'No Motion' vs 'Freefall'

In the AN12004 Application Note, the basis for detecting both 'No Motion' (3.2) and 'Freefall' (3.4) is that all 3 axes are within some threshold.

So that's the key to distinguishing 'No Motion' and 'Freefall' - as they're both detected on the same basis?

Accelerometers

Re: FXLS896xAF AN12004 - 'No Motion' vs 'Freefall'

Still wondering about the significance of Data[n]-Data[n-1] vs Absolute reference?

Also, rather than using the 'AND' logic of all 3 axes, what would be the pros/cons of just using the VECM (vector magnitude) ?

Re: FXLS896xAF AN12004 - 'No Motion' vs 'Freefall'

So you're just assuming that a "brief" period of "no motion" must be "freefall" ?

The other difference is that the "no motion" example uses the Data[n]-Data[n-1] reference update mode, whereas "freefall" uses the Absolute mode.

What's the significance in that?

Re: FXLS896xAF AN12004 - 'No Motion' vs 'Freefall'

Hello Andrew,

The key to distinguishing between the two lies in the setting of the debounce time (2.55s vs. 100ms). And yes, we also recommend to use slightly different threshold values (±100mg vs. ±200mg).

BR, Tomas