I love the warm glow of Nixie displays, probably as much as everybody else.
A few years ago, I was given by an uncle, an old nixie tube he had lying around from school (he’s a teacher) and I was told I could light it up with a 220/125V transformer. And I did it, and it was awesome. I had never seen that near, such a warm glow. It reminded me of those old candlelike bulbs I remember seeing, like 20 years ago:
Fast forward some years. I remembered that Nixie I had lying around, and, that many years later, I thought I might give it a go to make a pendant. I also had this friend in a low moment, and I dediced to improvise a Dieselpunk photoshoot to cheer her up a bit. (and also have a nice model for the pendant, if I managed to get it to work.
Since it was improvised, I didn’t had much time to get the nixie working. I happened to have a used electroluminiscent driver from work, rated at 5/100V, and supercharged it with 12V, thus having around 200V at the output. Yeah, you guessed it, efficiency went down the drain in there, but it worked:
Here’s the part I most proud of.
I didn’t had time to properly dress the nixie the day before (because you really shouldn’t hang the glass bulb as is, it’s not honorable). So, I carried with me some thin double sided tape, solder wire and other bits and tools. While my friend was aplying some makeup, I sat down at the bar and improvised. (if you have read other blog entries, you already know I’m really good at improvising).
I must acknowledge that the driver got quite hot (around 70ºC), but went through the day with no problems at all.
Some solde wire, double sided tape, foam bits and 30 minutes later, I had this on the table:
It’s so beautiful!! I might not say that…but it is!)
Some more photos:
The trick there, is to use the actual solder wire to hang the nixie (using the double sided tape as insulator) and have the 12V RC Li-Po battery and driver, hanging in the back. Yep, the girl has 200Vac around her neck, however, was well aware of the fact, and we were careful not to let it touch her skin.
Recently, I found the nixie again(with the solder wire still around it) and altough that was a while ago and I no longer speak with her, I thought Imight give it a second round, with more time, resources and knowledge. And because a nixie pendant/pin, would be awesome.
If you look at the old EL-transformer, it was big, bulky and, well, not suited for the task. In the meantime between that hack and this one, I had been playing around with flash tubes and drivers. I learned tons of things about flash, high voltage and xenon lamps (besides NOT discharging 10 photoflash caps in your finger, it HURTS).
That was a flash grenade for airsoft, but never worked reliably because the ionizing transformer was too small. But when it did…well, imagine:
Anyhow. I already had experience with photoflash transformers. Those pump 300V from 1,5V, so it should work. (later, I found some people driving nixies with a disposable camera as is). I picked a transformer I had lying around from those experiments, and using a simple 2N3904, driven by my DsoNano frequency generator, proceeded to check it’s output.
As you might remember from old cameras, flash had this high pitched sound that indicated charging. That means it was operating at some audible frequency, or at a multiple of it. Altough it is cool for a flash grenade to sound like that, having that whine around didn’t appeal to me, so I was relieved to see that the transformer worked at 20Khz 50% duty with no problems.
Adding a 1N4007 for half wave rectification and a ballast 120Ω resistor to limit current was enough to do the job. At 0,25W, nothing gets hot, so we’re ready to go.
Now that it works AND the power source is small, I plan to drive it from a 12F pic. Given that the transformer is actually smaller than my index fingernail, I will be able to put it underneath the tube and easily conceal it, so you only have 3,5V around your neck. Also, limiting the battery output to, say, 100mA, will protect the wearer against water inmersion. (we all know how parties end, and this is something you only wear in parties).