old ball mice that he had purchased for just such an occasion. (Yeah, right.) Since a ball mouse is essentially an upside-down trackball, all that remained for him to do was reverse-engineer the ...

Keeping track of your 3D-printer filament use can ... [Bin Sun]’s build is based around an old ball-type PS/2 mouse, the kind with the nice optical encoders. Mice of this vintage are getting ...