Making Nixie tubes from scratch

Light from the bygone era

A Nixie tube is a vacuum tube filled with gas at low pressure, primarily neon and a bit of argon or mercury. The sealed glass tube contains a wire-mesh anode and a number of wire cathodes shaped like the numbers 0 to 9. Thin ceramic spacers separate the cathodes from each other.

The gas atoms in the tube are at low-pressure. When a voltage in the range of 170 to 250 volts is applied between the anode and cathode, the atoms of neon gas split apart inside the tube into positively charged ions and negatively charged electrons, creating a plasma inside the tube. The positive ions are attracted to the negatively charged cathode, while the negative electrons are attracted to the positively charged anode mesh.

When the positively charged ions hit the cathode, some of them knock out energetic electrons. These are attracted to the positively charged anode. As the gas atoms, ions and electrons collide, they absorb energy and are “excited.” As they then lose this energy, they emit photons of light which create the red glow we see.

By controlling the flow of electricity to the differently-shaped cathodes, different numbers can be lit up.

The numbers in a Nixie tube can be used in displays to tell time, count, or for a range of other uses.

The tubes were originally developed by the Haydu Brothers Laboratories, founded by two Hungarian brothers in New Jersey. Haydu was purchased in the 1950s by the Burroughs Corporation, which then commercially produced and marketed Nixie tubes.

The name “nixie” was coined as a joke. According to one story, a draftsman sketching out designs for one of the tubes marked his work “NIX1” (Numeric Indicator Experimental#1). The nickname stuck, and Burroughs eventually trademarked the name “nixie” (“electronic indicator tubes”). The tubes were also extensively produced in the Soviet Union.

Nixie tubes had a good run till the 1980s when LED and LCD displays took over.

The archaic tubes were considered deceased until a sudden boom in 2005 when people in Russia and Ukraine began searching through the old stock and selling them online at prices lower than the original cost of production.

Farny, however, had no idea until he came across the technology on the internet in 2011.

“At the time, I was interested in high-speed photography with flash. I’d come across a photographer who tinkered with a special flash that made the photo resembles a frozen explosion. I wanted to do the same and was searching for gas discharge tubes online. Amid the search, I spotted a distinct image…, that was the first time I saw a Nixie tube,” Farny tells Interesting Engineering (IE).

Imbibing from the past, living in the present

Farny was fascinated.

An electronics enthusiast, he was constantly on the lookout for new projects to tinker with. He abandoned his high-speed photography project and ordered his first Nixie tubes, the small Russian-made IN-14 tubes, from eBay. But the tubes were tiny, and he wanted bigger ones. Farny decided to make them himself, although little information was available on how to do this.

Sourcing materials related to Nixie tube manufacturing proved to be extremely ambitious and burdensome. In fact, Farny spent the first three years solely gathering information and the high-quality materials needed to produce the finest Nixie tubes.

He first conducted experiments with gas discharge in the air. Then he developed a high-voltage power supply. Later, a skilled maker of vacuum tubes named Ron Soyland shared his expertise with Farny, which the latter credits as an important milestone.

The work involved was extensive – and tiring. Over the years, Farny managed to acquire a helium leak detector, build a glass lathe, and finally, after several attempts, he built his first Nixie tube in 2013.

The same year, he had his first opportunity to display his Nixie clock at a glass-art contest. ‘ShanghaiTime,’ his two-tube Nixie clock, involved two months of designing, programming, and manufacturing.

After this, Farny made a six-tube clock board named the Zen Nixie Clock, which was connected to the internet and included display effects that could be adjusted in real-time from the user’s account.

The Blub Nixie Clock is constructed with a single Nixie tube that displays the entire clock. Because it only has one tube, it is less expensive than other Nixie clocks and thus more widely available. The clock is based on the Arduino platform and can be updated over a USB port. Users can even write their own firmware for it. Another one, called the Bombe Clock, has its roots in Alan Turing’s ‘Bombe’.

By this time, customer requests began flowing in, but the limited availability of materials and dealing with products that became faulty after shipping was beginning to eat into Farny’s life.

The technology’s archaic nature kept Farny hooked, but later, it was the customers who kept him going. “My customers were very interested in the obstacles we faced and how we solved them. Their positive feedback was a major boost,” he says.

At the intersection of art and technology

One of his notable projects includes building a clock for NASA.

In 2019, Farny received an email from the US Space Agency. They were looking for a clock that could take an Inter-Range Instrumentation Group input. The group prepares and disseminates recommended standards in range instrumentation (such as that used in guided missile test ranges). They wanted a time display that could be photographed with high-speed cameras to verify the accuracy of range instrumentation. Decades ago, the agency had used Nixie tube displays that showed the timing down to 1/1000th of a second and wondered if Farny’s Nixie tubes could do the same.

Their interest was significant to Farny’s work because it was the first time he was asked to build a project with Nixie tubes based on the way they worked rather than on how they looked.

Over the next few months, Farny and his small team got down to work. Their first task involved finding the maximum frequency the Nixie tube could reliably switch between digits. They then implemented the IRIG-B 123 interface and designed the electronics. After six long months, the display was shipped to the Kennedy Space Center. NASA later informed Farny that his display made testing much easier.

“Unlike NASA, most of our customers see Nixie tubes as a technical piece of art. I think they appreciate the fact that someone is keeping old technology alive, and therefore, they want to support us,” he says.

Farny’s castle, as royal as it might sound, may not be the best location for his experiments. “I like the castle, but it isn’t practical for our work. There are no loading or unloading bays, and the place is extremely humid, which is inconvenient for both the production and the employees. So we have these air dryers running constantly, which costs us quite a penny for the electricity. But the building has a spirit, a soul. It makes us want to stay,” says Farny.

His clock is ticking

In April 2020, Farny was tasked with a huge new project – A 5x5m wall installation, covered with 121 brand new nixie tubes that are 150 mm in diameter – on which he continues to work.

“It turned out to be much more difficult than I thought because the materials behave differently when enlarged. The glass keeps breaking – currently, we’re finding ways to eliminate the problem and get a higher yield. Though we’ve made 25 Nixie tubes for the project, only four or five are working the way we’ve envisioned,” says Farny.

This is the primary reason why he doesn’t take up custom projects anymore.

“It’s honestly scary. You can never foresee the problems. Initially, we had six months to work on this project – It was intended for an exhibition in Asia. But I couldn’t complete it on time as I’d underestimated the difficulties. Then COVID struck, and that museum had to be closed down. Now I’m hoping to finish it in 2023,” he continues.

Farny hopes the next generation will carry his legacy forward. “For this very reason, I’m disseminating knowledge to more employees, and later my children [If they’re interested],” he adds.