Neon Display for a Vacuum Tube Calculator

When it comes to vintage displays, everyone gravitates to Nixies. These tubes look great, but you’re dealing with a certain aesthetic with these vintage numeric tubes. There is another option. For his Hackaday Prize entry, [castvee8] is making seven-segment displays out of vintage neon lamps. It looks great, and it’s the basis of an all-vacuum tube calculator.

The core of this build are a few tiny NE-2 neon bulbs. These are the same type of bulbs you’ll find in old indicators, and require somewhere around 100 volts to fire. These bulbs are then installed in a 3D-printed frame, giving [castvee] a real seven-segment display, a plus or minus sign, and an equals sign. It’s the beginnings of a calculator, right there.

One of the recent updates to this project is controlling these displays with modern logic. That might be a bit of a misnomer, because [castvee] is using diode steering and a TTL chip to cycle through the numbers 1 to 4. The actual code to do this is running on a microcontroller, though, so that might get a pass. This is just a test, though, and the real project looks to be an all-vacuum calculator. The project is still in its early stages, but there are still months to go in the Hackaday Prize, and we can’t wait to see what comes out of this project.

9 thoughts on “Neon Display for a Vacuum Tube Calculator

  1. It does have a look with a certain size and appeal. It does. But it is rather a prehistoric-like wolly mamouth to the nixie-tube’s sleeker, smaller elephant. I wo der if some sort of tubing, whether light amber latex or other. might be cut into a length perhaps 25% longer, split if needed, and placed over the NE2 to lengthen it and make the elements join just a tad better, and still yield the slightly clear, slightly fuzzy look of nixies, esp by bringing the 2 discrete vertical lamps slightly more together, visually. Well, print up some B+ Batteries for that 100vdc & pack this calulator in an old black domed lunch box! You know where the battery goes…! 🤔

    1. I tried some of those variants with little to no love. I haven’t totally given up on the idea, but have grown to like the appearance. They are so damn easy to make it’s an addiction now. The tube projects still are not out of my system yet either but am hoping the fever dissipates soon. I had not done anything with tubes for 35 years and now just seem to get in deeper with every machine. If the saying is “Real radios glow in the dark” then these are massive piles of thermal nightmares in the making…….My filament transformer supply has been stretched to the limit.

      1. I know what you are saying, I have spells lasting weeks where tubes, valves and old radios occupy my existence, and then I return to other projects until the urge returns.

      2. “real radios glow in the dark” ? ….you forgot to add “REAL radios can KILL you!” hehehe (ever get bit by the HV supplies on say an old Heathkit HW-101) ? Also speaking of Heathkit. Instead of using neon tubes, perhaps the gas planar displays Heathkit used in their GC-1005, GC-1092 clocks would be a better choice. In fact they did have a calculator using those same displays. The orange glow and *precise* clean lines of the digits were very tech-sexy. I still have my GC-1005 clock I built in 1976 still running strong to this day !

    1. My goal was never to build a nixie, compete with a nixie or fashion a replacement for one. It was to make a unique display that was vintage looking for my experiments.

      1. Don’t get me wrong, it’s still a very nice and neat work. All I said was that it’s still not as good as the old nixies.I have been thinking about displays also and was wondering if there could be any other possibility at that time. Some kind of hybrib electro-mechanical device with mini-magnets and relays. That sounds too steampunk maybe…

  2. No offense intended, then or now. But it is a bit like Frankenstein; large, crude, but not totally withouy its own charm just due to that Frankie was a hack and so is this. Humans, compare. Build a gorgeous one-off and it will get compared to anything that has any commonality. This is like a simple clock, maybe with big wooden gears, in one regard. Not so svelte. Rustic! You can see its guts. Not a bad thing. A type of charm. Nixies were not so perfect and had their own rustic appeal… if a tad more svelte. These could grow on you… or on a kid who gets them as a kit.

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