LIS2DW12

Msaga.1 · ‎2021-05-04

There saw that there is no gyroscope in this model, so I dont understand how we can to differentiate between (for example) - stationary mode, when we have g in the X axis and '0' on the other. AND movement so there is g in X axis and '0' on other axis (perhaps movement on one of the axis).

how can we tell if we are stationary \ moving in this example.

niccolò · ‎2021-05-04

Hi @Msaga.1 ,

I did not fully understand the question, but

if you have a value of 1 g on one axis and zero on the others for more samples in a row, your device is stationary.

in general, if the values of the accelerometers are stationary (they can change because of noise, but it is a very small change) the device is stationary.

to understand if you are moving, you need to check several samples in a row.

in the easiest case: if your signal is stable until sample in t0 and in sample t1 the value has changed by a not negligible amount, you know there was a movement (this is how the wake-up interrupt works, in a simplified way)

if I did not answer you properly, please, try to rephrase your question so that I can better understand it.

Niccolò

View solution in original post

niccolò · ‎2021-05-04

Hi @Msaga.1 ,

I did not fully understand the question, but

if you have a value of 1 g on one axis and zero on the others for more samples in a row, your device is stationary.

in general, if the values of the accelerometers are stationary (they can change because of noise, but it is a very small change) the device is stationary.

to understand if you are moving, you need to check several samples in a row.

in the easiest case: if your signal is stable until sample in t0 and in sample t1 the value has changed by a not negligible amount, you know there was a movement (this is how the wake-up interrupt works, in a simplified way)

if I did not answer you properly, please, try to rephrase your question so that I can better understand it.

Niccolò

Msaga.1 · ‎2021-05-05

thank you

APipm.1 · ‎2021-05-24

Hi!

There seem to be two scenarios between which we can't distinguish:

A stationary device. Lets assume the X axis is facing towards the earth.
A free falling device, with the Z axis facing towards the earth, and a constant force with acceleration g applied towards the X axis.

From what I gather, both scenarios will report the same measurements, a ~1000mg value read in the X direction, and a ~0mg value read in all other axis.

I've added an image showing these two scenarios, could you take a look and comment your thoughts please?

Msaga.1 · ‎2021-05-24

@niccolo.ruffini Hi Niccolo, please see the question by @APipm.1 above.

niccolò · ‎2021-05-25

Hi @APipm.1 and @Msaga.1 ,

the situation you describe is very peculiar and I'm afraid in that case (with only the data in that moment) you can't know which scenario is detected by the sensor, because the data should be the same.

anyway, you should be able to know which is the starting position of the device, so you can pinpoint the exact scenario

hope I could explain myself

Niccolò