8-Bits And 1,120 Triodes

While it’s currently the start of summer in the Northern Hemisphere, it will inevitably get cold again. If you’re looking for a unique way of heating your workshop this year, you could do worse than build an 8-bit computer with a bunch of 6N3P vacuum tubes. While there are some technical details, you might find it a challenging build. But it is still an impressive sight, and it took 18 months to build a prototype and the final version. You can find the technical details if you want to try your hand. Oh, did we mention it takes about 200 amps? One of the prototype computers plays Pong on a decidedly low-tech display, which you can see below.

The architecture has 8 data bits and 12 address bits. It only provides six instructions, but that keeps the tube count manageable. Each tube has two triodes in one envelope and form a NOR gate which is sufficient to build everything else you need. In addition to tubes, there are reed relays and some NVRAM, a modern conceit.

Operating instructions are to turn it on and wait for the 560 tubes to warm up. Then, to quote the designer, “… I check the fire extinguisher is full, and run the code.” We wonder if one of the six instructions is halt and catch fire. Another quote from the builder is: “It has been a ridiculous amount of soldering and a fantastic amount of fun.” We can imagine.

If the computer seems familiar, we covered the first and second prototypes named ENA and Fred. We’ve also seen tube-base single-board computers.

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DIY Tube Lights Look Amazing For Just $50 A Piece

It’s the future. We should have weird glowy lights everywhere, all over our homes, cars, and businesses. In the automotive world, luxury automakers are doing their part with LED ambient lighting systems, but the rest of us have to step up. [Super Valid Designs] has developed an excellent modular DMX lighting rig that’s fit for this purpose; the rest of us just have to get to work and build our own!  (Video, embedded below.)

The design relies on hot-swapping powered bases that let a variety of different lights to be swapped in as needed. They use a custom four-pin socket designed by [Super Valid Designs] using PVC and ABS plumbing and conduit parts and tent pole springs from Home Depot. There’s a 3D-printable version, too, which is useful for those around the world that can’t get access to American standard gear easily. Anyone from the Nerf scene will understand this frustration well.

The real cool part of the modular rig, though, are the tube fixtures. There’s a ball design too, but they don’t look quite as future-cool as the tubes. They use fluorescent tube protectors as a cheap source of clear tubes, and use plumbing and conduit parts to make easy-insert connectors for pairing with the modular bases. Light is courtesy of old-school non-addressable RGB LED strips, attached to flat aluminium trim with their own adhesive combined with a wrap of clear packing tape as well. The LED strip is attached to one side of the tube, with parchment paper layered inside the tubes to act as a diffuser.

Building in quantities of 8 or more, [Super Valid Designs] reckons that the tubes can be built for $50 each or less. Of course, that adds up to a few hundred dollars in total, but the results speak for themselves.

If you’re thinking of tackling this project, but DMX is beyond your current skillset, fear not. We’ve got just the primer to get you started! Video after the break.

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A dekatron-based clock with a GPS receiver and a plastic dinosaur on top

Dekatron Clock Tells The Time, Sans Semiconductors

Over the years, there have been several memory and display technologies that served a particular niche for a while, only to be replaced and forgotten when a more suitable technology came along. One of those was the dekatron: a combination memory and display tube that saw some use in the 1950s and ’60s but became obsolete soon after. Their retro design and combined memory/display functionality make them excellent components for today’s clock hackers however, as [grobinson6000] demonstrates in his Dekaclock project.

A dekatron tube is basically a neon tube with ten cathodes arranged in a circle. Only one of them is illuminated at any time, and you can make the tube jump to the next cathode by applying pulses to its pins. The Dekaclock uses the 50 Hz mains frequency to generate 20 ms pulses in one tube; when it reaches 100 ms, it triggers the next tube that counts hundreds of ms, which triggers another one that counts seconds, and so on with minutes and hours.

The Dekaclock uses no semiconductors at all: the entire system is built from glass tubes and passive components. However, [grobinson6000] also built an auxiliary system, full of semiconductors, that makes the clock a bit easier to use. It sits on top of the Dekaclock and automatically sets the correct time using a GPS receiver. It also keeps track of the time displayed by the dekatrons, and tells you how far they have drifted from their initial setting.

Both systems are housed in sleek wooden cases that perfectly fit the tubes’ retro aesthetic. [grobinson6000] was inspired to make the Dekaclock after watching another dekatron clock we featured earlier, and designed the GPS receiver to work alongside it. Dekatrons are surprisingly versatile devices: you can use them to make anything from internet speed gauges to kitchen timers.

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Hackaday Prize 2022: Glass Tube Solar Thermionic Converters

Typically, if you want to convert solar energy into electrical energy, you use either photovoltaic (PV) cells, or you use the sunlight to create steam to turn a turbine. Both of these methods are well-established and used regularly in both small- and grid-scale applications. However, [Nick Poole] wanted to investigate an alternative method, using thermionic converters for solar power generation.

[Nick] has been gearing up to produce various styles of vacuum tubes, and noted that the thermionic effect that makes them work could also be used to generate electricity. They are highly inefficient and produce far less power than a photovoltaic solar cell, meaning they’re not in common use. However, as [Nick] notes, unlike PV cells etched in silicon, a thermionic converter can be built with basic glassworking tools, requiring little more than a torch, a vacuum pump, and a spot welder.

Experiments with a large lens to focus sunlight onto a 6V3A diode tube showed promise. [Nick] was able to generate half a volt, albeit at a tiny current, with the design not being optimized for thermionic conversion. Further experiments involved electrically heating a pair of diode tubes, which was able to just barely light an LED at 1.7 V and a current of 7.5 uA. The conversion efficiency was a lowly 0.00012%, around 5 orders of magnitude worse than a typical PV cell.

[Nick]’s hope is that he can produce a tube designed specifically to maximize thermionic conversion for energy generation purposes. It’s likely there is some low-hanging fruit in terms of gains to be made simply by optimizing the design for this purpose, even if the technique can’t compete with other solar generation methods.

In any case, we’re eager to see what [Nick] comes up with! We love to see makers building tubes in their own home workshops.

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Antique Beat Box Showcases 1950’s Engineering Prowess

Before you could just put a drum machine app on your phone, or fire up Garage Band, there were breakthroughs like the Roland 808 drum machine. But that’s not where it all started. In 1959 a company called Wurlitzer (known for things like juke boxes, pianos, and giant pipe organs) produced a new device that had musicians worried it would put drummers out of a job: The 1959 Wurlitzer Sideman. And in the video below the break, we have the joy of watching [LOOK MUM NO COMPUTER] open up, explain, and play one of these marvelous machines.

Can you spot the early circuit sculpture?

It’s noteworthy that in 1959, almost none of the advancements we take for granted had made it out of the laboratory. Transistors? Nope. Integrated Circuits? Definitely not. What does that leave us with? Vacuum tubes (Valves for those across the pond), resistors, capacitors, relays, and… motors? Yep. Motors.

The unit is artfully constructed, and we mean that quite literally- the build was clearly done with care and it is easy to see an early example of circuit sculpture around the 3 minute mark. Electromechanical mechanisms take on tasks that we’d probably use a 555 for these days, but for any of you working on mechanical projects, take note: Wurlitzer really knew what they were doing, and there are some excellent examples of mechanical and electrical engineering throughout this primordial beat box.

If you move to the beat of interesting drum machines, you might enjoy this Teensy based Open Source drum machine that you can build. No tubes required!

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Semiconductor Shortage? Never Mind That, There’s A Vacuum Shortage!

As those of us who work in electronics are grappling with a semiconductor shortage making common devices unobtainable and less common ones very expensive, it’s worth noting that there’s another supply crunch playing out elsewhere in the electronics industry. It’s not one that should trouble most readers but it’s a vexing problem in the guitar amp business, as guitar.com reports. At its root is the Chinese Shuguang factory, which it is reported has been forced to close down and move its operations. There’s nothing about this on the Shuguang website, so we hope that the plant has been relocated successfully and production will resume.

The specialist audio market that forms the lion’s share of tube customers in 2021 is a relatively tiny corner of the electronics business, but it’s interesting to note that the three major plants which supply it, in Slovakia, Russia, and China, are still not enough to prevent it being vulnerable when one of them fails. The likelihood of a fourth tube plant emerging somewhere else in the 2020s to take up the slack is not high, but it’s evident that the demand remains healthy enough.

If you’d like to know more about the supply of new vacuum tubes, we went into the subject in greater detail last year.

Retrotechtacular: Nuvistor, Vacuum’s Last Gasp

In 2021 all our electronics are solid state, in that they exclusively use semiconductor devices as their active components. Some of us may experiment with vacuum tubes, but only for curiosity or aesthetic purposes. Semiconductors have overtaken vacuum devices in all but the rarest of niche applications due to their easier design requirements, greater reliability, lower cost, and increased performance.

It was not always this way though, and there was a period at the start of the semiconductor era when transistors and vacuum tubes existed together side-by-side and competed directly. Vacuum tube manufacturers continued to create new devices into the 1970s, and in doing so they pushed the boundaries of their art in unprecedented directions. [David W Knight] has a page dedicated to the Nuvistor, something his calls the “final evolution of the thermionic valve”. His comparison photo seen above shows a Nuvistor on the left — a miniature vacuum tube you’ve likely never seen before.

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