I wasn't really happy with the headphone holder though. It has been working well, but I wanted something simper (to use). The current iteration is shown below. It uses a spring from a ball point pen that pushes a claw which engages on the geared edge of the cable reel. The idea is to lock it in place when it is coiled up, so it does not get loose, but it should be easy enough to turn that it can be spun to reel it up with a finger or two. I have still gotta test it, but I printed the parts of the claw and spring holder and that all works. If it all goes well (and it never does), it should be posted this week or next.
Update: here they are: