One of the thing I liked on the different videos of the UP! I've seen is it's original filament unrolling system. It used a very clever system with a dedicated motor that could free some filament from the spool when needed. It seems that this feature has disappeared, or maybe it's an option.

The fact is that the UP! I'm testing doesn't come with it and the way the spool gets hold could be improved...

So I decided to build up a better spool holder.

UP! Lego spool holder