Object Review - Nixie clock.

My bedroom clock failed a few weeks ago. It was a new-old-stock 1973-ish Westclox of Japanese manufacture, and had run for me, without fail, for maybe two years. I may make some attempt to revive it some time, but not having the electronics kung-fu of my dad, I'm not optimistic about the effort. So. New clock time.

I'd managed to find out the name of the super old digital displays that are beloved of Steampunk hipsters - Nixie tubes. Those are the glowy orange numbers that live inside a glass tube about the size of a man's finger. Steampunk guys, by definition, have a certain disregard for chronological continuity, and so have no problem mixing in Nixies, which are a 1950s technology, with their victorian stovepipe hats and clockwork brassieres.

A Nixie tube from my dad's collection of bits. Note 

the wires connecting to the post inside the tube.

These correspond to the numbers cathodes in

the stack.

A notable pop culture occurence of Nixies can be found in the Anime epic, Wings of Honneamise, if I recall. I can't be bothered to watch the whole thing again to make sure, but I seem to recall one of the control panels in a spacecraft having a Nixie digital readout. Since they were the first type of digital electronic display to be invented, they are the go-to technology for retrologists and weirdos who like their equipment to look unbelievably complicated and fragile.

"Nixie" = "Numeric Indicator eXperimental No. 1", trademarked by the Burroughs coproration. It's become the "Band-Aid" / "Kleenex" name for any tube-based display of this type.

A nixie tube is basically a sealed glass bubble filled with some mixture of neon gas, one anode (electrically charged wire thingy) and several cathodes (other wire thingies), made in the shape of digits. Pins protruding from the back / bottom of the Nixie correspond to the various numbers inside. When current is supplied to a combination of pins, that digit lights up. Because the numbers are stacked on top of each other, there is a distinctive visual depth to the function of a Nixie as the numbers change.

Turns out I had a handful of Nixies, inherited from my dad in a huge chest of electronic components in my garage. They come in various shapes and sizes. The ones pictured here were my dad's. They're not part of the clock, but they're handy for examination without manhandling the delicate innards of the clock.

Nixies became widely used in scientific and aerospace applications in the 50s and 60s, but were being developed as early as the 1930s. After being supplanted by simpler, cheaper, more durable LED technology in the seventies, they fell out of use and sat on warehouse shelves until a bit of a retro revival in the 1990s. Prices have risen sharply because of this, and you can now buy Nixie clocks (in either kit or completed form) on the web.

A Google search brought me to Peter Jensen's site, where he sells Nixie clocks and kits. They can be pretty expensive, depending on whether you want to build it yourself, or have it in a super cool machined case or what have you. Not being able to justify the price of a CNC'd aluminum case, I opted for the "prorotypey" look of the bare electronics, assembled for me by Peter himself (I think). As per his recommendation, I then ordered an acrylic case from a separate specialty supplier.

Despite the fact that Nxies run very cool to the touch, I drilled some 1-inch vent holes in the back of the case, because I just happened to have some press-fit mesh grilles - also courtesy of dad's parts chest - to go back there. The vents help it to look over-engineered and complicated.

The clock has two buttons on the circuit board that function pretty much like the ones on a digital watch, setting the time and brightness, etc. Peter has added a few surprising features, like a dimmer timer, which basically lets you set a schedule to dim the Nixies, presumably prolonging the life of the tubes, which can be had from Peter for about $20 each. Alternately, if a tube fails, you can just send the clock back to him and he'll do whatever it takes to get it going again. Nixie tube service life is generally in the thousands-of-hours range. Peter unofficially predicts the life of his clocks to be about five years before servicing is necessary. Being a little pessimistic about whether or not Jensen is still in the biz in five years, I kind of want to order a few replacement tubes from him while I still can. Additionally, there is a clock speed adjustment function that I haven't had the need to mess with, but it's there. The clock seems to keep pace with my cell phone, a week after setting it.

If you get the "naked" version of the clock like me, you can possibly look forward to powering it up for the first time with your finger absent mindedly touching the pins on the bottom of one of the Nixies, protruding from the underside of the circuit board. The voltage is enough to get your attention.

So what's with the dark square over the seconds display? I found that, staring at the clock while falling asleep, the seconds ticking by could be a little distracting, even with the clock set to the lowest brightness, as shown here. Watching seconds go by while you're trying to fall asleep can have a bit of a "hurry up and sleep!" effect on the brain. This is not restful. That's two pieces of transparent acrylic held together with a nut and bolt, leaning against the two rightmost tubes. I combined a piece of red and purple plastic from a set of color filters. They're intended to be used as gels, over the flash or lens of your pocket camera. A set of about eight filters costs an extortionate $15 or so from a photography site, but here's a tip... Go to a plastics site like Delvie's Plastics and order a "sample kit". It will be pretty much the same thing for about five dollars. Anyway, with the seconds dimmed down to a deep purplish-red, the ticking away of the numbers no longer changes the ambient glow of the room sixty times a minute, which doesn't interfere with sleep, but you can still watch them do their thing if you want to, the numbers moving forward and back in their wire cathode stack, in time with the pulsations of your brain.

The case is recommended by Jensen himself, and comes from Cases for Collectibles.com, which doesn't seem to be affiliated with Jensen at all. It's a 4"x4"x8" case and fits the clock perfectly. The little stick-on feet that came with it seemed a little underwhelming, so I went back to dad's parts chest and found four rubber feet about an inch in diameter, some screws and brass cap nuts (or "acorn nuts" as dad used to call them) to hold them on. Some more drilling and before long, the feet not only made it look more "finished", but also contribute mightily to the retro appeal.

Pro tip: Acrylic scratches only slightly less than butter. When drilling or working with it, cover the surface with masking tape. It doesn't make it indestructible, but you can mark on it with a sharpie and you're way less likely to ding the surface with an errant drill bit or utility knife. The tape should leave no residue when you peel it off.

Even in the economical caseless form, the cost of a clock like this is non-trivial. However, they are ex-Soviet tubes not mass produced, soldered by hand onto a custom circuit board by an independent businessman not in China. Tell yourself you're helping the economy.

FULL DISCLOSURE: There is nothing to fully disclose. I paid for this clock with my own money and Peter Jensen doesn't even know I'm doing this write-up. However, if he sees this post and wants to shower me with free stuff or something, I welcome the opportunity to totally sell out in this way.