Nixiedisp is a 6-digit nixie tube general purpose numerical display over USB I'm working on, that also works as a standalone clock (no USB connection required). This is a short video putting the current version of the under development firmware through its paces. As always, hardware design and source code are free under the GNU General Public License v3 or later: https://github.com/jtsiomb/nixiedisp
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https://www.youtube.com/watch?v=OrqBnmfFbgk