In the anime, the star compass is always pointing downwards. So I had the idea to use a gimbal to achieve this behaviour.
- transparent plastic sphere Ø 10cm (not printed)
- star top part (hollow and extremely light)
- star bottom part (printed very dense and has an indentation to add sand to make it as heavy as possible)
- compass needle (printed in 2 parts)
- halo (ring outside the sphere)
- inner gimbal ring
- outer gimbal ring
- 2 plugs to connect the outer ring to the sphere and hold the halo
- tool to mark two opposite points on the shpere
I've been working on this for a while now, but I can't get it to work. The joints I designed for the gimbal get stuck all the time. I have to shake the whole thing to make it move.
This is a section view from top. (red: inner ring, green: outer ring, blue: sphere)
And a closer one.
The rods are 2mm in diameter and the holes are 2.4mm. I also added a chamfer to it so the rings and the sphere used for the gimbal don't get too close (at least in theory; it doesn't seem to be working that good).
The distance between the two rings and the shpere is 2mm.
I printed all the gimbal related parts in PET (probably a problem?).
I have no idea what I could do to make it work. Any help is greatly appreciated.