North pole connection revisited

A project log for Earth globe laser tracker

Track an object with laser on a earth globe

londlond 07/01/2021 at 19:330 Comments

After getting the electronics to work I realized that the magnet in the north pole wasn't correctly aligned with the angle sensor and made the laser dot deviate +-5° when turning the earth globe.

According to the specification of the AS5600L, the maximum allowed displacement of the rotational axis of the reference magnet from the center of the package is 0.25 mm when using a magnet with a diameter of 6mm. I'm using a magnet with a diameter of 10mm, I think that I shouldn't deviate more than 0.25mm anyway...

My solution was to mount the magnet on a axel and a bearing that is fixed with the sensor

And to make the magnet to rotate with the earth globe a new north pole connection was designed

And here without the earth globe

And after this design change the deviation of the laser dot isn't noticeable at the equator :)

I can now continue with the user interface...