MMA8453Q - Interpreting XYZ Data individually - HPF low power active

[mikepedersen]

Im currently monitoring acceleration while driving. 

High pass filtering is active with default value 0.25 Hz

Data rate is 6.25 Hz

Im struggling with how to identify acceleration on a single Axis?

My initial idea was to measure a baseline with the accelerometer in a fixed position, and then subtracting that baseline from my movement data. However this doesnt seem to give me any usable data without considering the data that should have been cut off by the high pass filter.

So my core question is how do i identify the values that should have been been filtered out?

My data consist of the xyz positional data.

The end goal is to be able to identify an exact threshold on which to have the accelerometer firing events.

[david_diaz]

Hello Mike,

Thank you for writing.

The output value from the accelerometer is contained at the data registers from 0x01 to 0x06 direction. This information must be converted to signed 14-bit values and afterwards to real values in g’s, which is the acceleration requested.

You may find more information at this sample project.

For details of implementation on the high-pass filter, refer to NXP application note AN4071.

I hope this information helps. Please let me know if I misunderstood your question.

Regards,

David