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Aha moment

Profile picture for user David Chandler
Submitted by David Chandler on Wed, 06/28/2017 - 23:34

I'm getting used to the orientation of the axes with my new Pocketlab in acceleration mode.

Initially I was expecting to orient the axes with the z-axis reading -9.8 m/s^2.  Wrong!  (I think.)  Letting the sensor sit on a table with the z-axis upward should read +9.8 m/s^2.  Think of it as sitting on the floor of an elevator accelerating upward.  It feels the push of the table under it (the normal force) pushing it upward.

This also gives a good way to identify the red and blue graphs and to tell which is the positive direction of each.  Orient the sensor so the red graph is at +9.8 m/s^2 and the x-axis at that moment is pointing upward.  Same process for the blue graph and the y-axis.

Letting the normal force give you a calibrating "acceleration" is smoother and easier to read than trying to shake the sensor.


--David Chandler