MMA8451 dynamic calibration

[ifdm]

Hi all, I'm using MMA8451 to calculate distance between two points. When travelling from 0->x and going back from x->0. The resulting distance is different from 0. I've read this is due to the device is not well calibrated. But the zero-g offset compensation is dynamically  done in the endings of the travel. So discarding this, is there any idea how to calibrate the device to not see this kind of problems?

[david_diaz]

Hello,

Have you tried to perform the calibration when there is a no movement condition?

Please note that the calibration value obtained will be affected by the board’s orientation and the static acceleration (earth’s gravity) component in each of the axis.

In case it is useful for you, you may refer to the following application note:

AN3397 - Implementing positioning Algorithms Using Accelerometeres.

I hope this information will be useful for you.

If I misunderstood your question, feel free to let me know.  I will be glad to help.

Have a great day.

David Diaz.

Note: If this post answers your question, please click the Mark Correct button. Thank you!

[ifdm]

Dear David,

Thanks for the note, it was really useful. The problem I'm facing is the one pointed in the document under the title "Movement End. Check". The thing is, depending on the accelerometer, when travelling in one direction the resulting speed at the end of the travel is positive, but travelling in the other direction, the resulting speed is negative. In any case, the resulting speed never is 0. If an offset is added to the acceleration then, the resulting speed is closer to zero for both travel directions.

Is there any method to calculate the offset that makes the speed at the end of the travel, in both directions, closer to zero?