CODEWITHSUNDEEP
pythontrigonometryaccelerometerangle
L.C.
L.C.

Reputation: 81

Trigonometry accelerometer Z angle from gravity vector (normal vector to X Y plane)

This one has had me scratching my head for a while. I have an accelerometer and am successfully measuring the X and Y angles with this great script: https://github.com/ozzmaker/BerryIMU/blob/master/python-BerryIMU-gryo-accel-compass/berryIMU.py

What I would like to calculate is the delta angle between the gravity vector and the Z axis (where Z is the normal vector to the plane created by the X and Y angles).

I have found some images on google and edited them to try to explain the issue. See below.

Angle of Z to gravity vector

If the script from githut above calculates X and Y as follows:

import math

RAD_TO_DEG = 57.295
ACCy = (see github script for details)
ACCz = (see github script for details)
ACCx = (see github script for details)


Xangle =  (math.atan2(ACCy,ACCz)*RAD_TO_DEG)
Yangle =  (math.atan2(ACCz,ACCx)*RAD_TO_DEG)

How would I calculate the Z angle delta to gravity vector as shown in the image? Would it be: 

Zangle = (math.atan2(ACCx,ACCy)*RAD_TO_DEG)

Upvotes: 1

Views: 958

Answers (1)

Aguy
Aguy

Reputation: 8059

math.asin(ACCz / math.sqrt(ACCx ** 2 + ACCy **2 + ACCz ** 2)) * RAD_TO_DEG

might be what you're looking for.

Upvotes: 1

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