Intertube Clock

Abstract

An old Systron-Donner counter with nixie tube indicators repurposed as an internet-connected clock.

What it’s made of

  • Systron-Donner model 1038 counter
  • ESP32 development board
  • Software written in C
  • Custom PCB designed in EAGLE
  • High voltage nixie tube power supply
  • 12v AC-DC power supply

How it works

The internet connection (and time, if set manually) is configured through a simple terminal interface. From here, an SNTP client running on the ESP32 fetches the current time.

Concurrently the ESP32 sets I/O pins to illuminate filaments in the nixie tubes according to the current time. The ESP32’s I/O pins connect to the high-voltage sink drivers already inside the counter.

I inserted jumpers between the parts inside the counter required to drive the tubes/indicators and the rest of the apparatus. This way running the clock didn’t take like 400W of power and howl like the winds of Kilimanjaro. If I ever wanted to use the counter in it’s original form though, I could by replacing the jumpers.

JUST KIDDING there are no solid-state drivers anywhere in this thing, it’s all diode-transistor logic so I’ll unfortunately have to insert my own driver circuit between the counter and the nixie tubes. Given the physical placement of the tubes at the proper height for readability and the insane rats nest of wiring and traces in this machine, I’ll be removing/destroying the existing tube sockets and placing an entirely new board with sockets atop the existing one. High-voltage insulation will be needed.

Also these ZM1030 tubes are dual-anode which makes the driver circuit more complicated with two necessary supplies to prevent ghosting.

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UFanders

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