topic ZSTAR3: How calculate relative accelerations? in Sensors

ZSTAR3: How calculate relative accelerations?

adekadek — Mon, 20 Oct 2014 20:42:04 GMT

Hi,

I have ZSTAR3. I want to calculate relative accelerations.
This means, when sensor stay on the desk I want to have using mathematical formula 0g in X,Y,Z-axis. When I moving I also want to calculate relative acceleration in X, Y, Z-axis.

For example. I have my sensor on hand and I begin move to up and down and I want to know with which relative accelerations in Z-axis I move this sensor.

Freescale programs give me only absolute acceleration in X, Y, Z-axis and absolute g.

My data from program of Freescale is in attachment.

Best regards
Adek

Re: ZSTAR3: How calculate relative accelerations?

TomasVaverka — Tue, 21 Oct 2014 10:05:23 GMT

Hi Adek,

In short, this is not easily achievable with the hardware and software used in the ZSTAR3 system.

My recommendation is to use the FRDM-FXS-MULTI-B board paired with compatible Freedom boards and running the Freescale sensor fusion library for Kinetis MCUs. See also One-stop-fusion-shopping at freescale.com/sensorfusion for more information on those evaluation boards and library.

Hope it helps.

Regards,

Tomas

PS: If my answer helps to solve your question, please mark it as "Correct" or “Helpful”. Thank you.

Re: Re: ZSTAR3: How calculate relative accelerations?

adekadek — Tue, 28 Oct 2014 07:30:40 GMT

Thanks Tomas,

I thinking about how calculate relative acceleration with ZSTAR3 but in my opinion this is immposible. You are right Thomas.

With this sensor I have only tilt and absolute acceleration in X,Y,Z-axis.

I can only calculate relative acceleration when i let go down without rotation. Then I can choose with all date

max acceleration and min acceleration(1g) and calculate relative acceleration = max acceleration - min acceleration(1g) in Z-axis.

But when I let go down and sensor is in position X-axis 45 degrees and Z-axis 45 degrees ( photo below) I can't calculate relativ acceleration

in X or Z direction.

I measure with this construction (photo) acceleration of falling sensors and angle of sensor is in X,Z-axis 45 degrees.

Of course i want to measure relative acceleretion in X,Z-acceleration

Maybe someone have different opinion?

Best regards
Adek