The clock features six ИВ-9 vacuum tubes to indicate the time and two incandescent "grain of wheat" bulbs as digit separators. Each tube has eight tiny tungsten filaments forming a seven-segment display with decimal point.
The PCB was designed in KiCad and uses mostly through-hole components for easy soldering and to keep in spirit with the retro tubes.
The tubes are driven by constant-current shift registers to prolongs the filament lifetime by limiting the current when the segments are lighting up. The segments take a while to turn on, resulting in a nice fade.
Numi features a laser cut panel case with an extra top cover that hides the finger joints.
