Numitron Neon Tube Display Driver
A circuit that drives 7-segment Russian Numitron tubes.
Background/Motivation
My friend ordered some Russian numitron tubes but didn't have a good setup for driving them. I offered to make a circuit for him that can be controlled by any microcontroller with 4 or more IO pins.
All information on these tubes was in Russian, so I had to take some time to (poorly) translate the documentation into English. I already had basic some knowledge on neon tubes, as I had built a nixie tube driver, which operates very similar, save for the heater, to the numitron tubes.
Design Process
7 segment displays need 7 signal inputs to control them. In a normal case, I would just use a driver IC for controlling these. However, numitron tubes require higher voltages to be properly visible, therefore, they cannot be switched using the normal 5V rated ICs. I constructed a circuit that uses normal HC595 shift registers with the outputs connected to ULN2003 transistor arrays for switching the high voltage.
For the protoboard design, I had to make several (very gross) adjustments to make the circuit work properly including unattractive jumpers, rough board cuts, and unsecured components.
Test Operation of Protoboard Design
Please watch the full video. There is more than the first loop
Future Designs
I have made a proper PCB design in EAGLE and I am awaiting its production. I have designed it to be modular so that any amount of numitron tubes can be chained together and controlled from a single serial signal.
Circuit and PCB
Parts
- HC595 (x3)
- ULN2003 (x3)
- Arduino Nano (Any microcontroller will do)
- Numitron Tubes (x3)
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