IMU parser parsing same data for axis c and d

[Kevinlzh9802]

Should line 76 be df['d'] = rotation_xyz[:,3]? I tracked here because I'm plotting IMU sensor data and axis and d are always showing identical data. It seems this already exists in the earliest version from Ekin.

Originally posted by @Kevinlzh9802 in d58baaf

[Gara-Dorta]

Yes, I think the index should be replaced from 2 to 3.

Just putting the line here for reference

midge-code/BadgeFramework/imu_parser.py

Line 112 in 970452e

df['d'] = rotation_xyz[:,2] # TODO: check if this is correct

Also, instead of using the (a, b, c, d), I would much prefer if we use the (x, y, z, w) convention. The mapping is
x = b, y = c, z = d, w = a

https://en.wikipedia.org/wiki/Quaternion
https://docs.scipy.org/doc/scipy/reference/generated/scipy.spatial.transform.Rotation.from_quat.html

[Gara-Dorta]

Could you please test this and make a PR for it?