AnsweredAssumed Answered

ADXL372 acceleration threshold

Question asked by FlyShock on Oct 13, 2017
Latest reply on Oct 19, 2017 by FlyShock

Hi everyone,

I have an ADXL372 MEMS accelerometer. It is working fine, I can read the data out of it and configure it.

There are several cases where I get into troubles.

The one I want to talk about is about triggering on acceleration thresholds.

 

The following parameters are applied:

ODR: 6400Hz

BW: 3200 HZ

High pass filter disabled

Activity threshold on all axis set to 10 (which is written as 100 since we should get 100mg/LSB)

   -->THRESH_ACT_X_H = 0x0C

   -->THRESH_ACT_X_L = 0x81   (same applied to all other axis)

Interrupt (INT1) mapped to Activity event

The activity timer is set to 0 (so as soon as I get a value above threshold, it should trigger)

 

 

From this I get 2 different scenarios.

If I set the threshold to 10G (as explained above), I never get any trigger. I can smash the board and nothing happen.
I checked the acceleration I get by reading the value while the sensor is set to stream data when ready, I can get peaks up to 150G.

 

If I set the threshold to 3G, I can trigger.

 

From what I observed, it looks like the threshold value scale is not what I expected or I am doing something wrong.

 

Thanks for your help.

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