this is the layout of a pcb i designed for a nixi clock.

the bigger tubes are for hours and minits, while the smaller ones are for seconds, and the things before seconds, micro seconds ?

theirs a few little bugs, i found when populating it, but nothing some bodge wires couldn't fix.

its designed to be controlled from a raspberry pi zero, because why not :P

in truth, its because i wanted it to update from wifi using NPT, and i wanted flexibility to display other things on the tubes, like broadband speeds. This uses the speed test . net api, and some code a friend wrote at So Make It (the maker space in Southampton uk)

ironical, i did find a I2C RTC (clock ticker chip) that counted micro seconds(?) but turns out the pi naturally keeps better time, on NPT alone.
so actual my clock is accurate to a significant place more than it can display.