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

Dekatron Clock Tells The Time, Sans Semiconductors

December 5, 2022 by Robin Kearey 19 Comments

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.

Continue reading “Dekatron Clock Tells The Time, Sans Semiconductors” →

Nixie Display Module Is Addressable Via SPI

December 3, 2022 by Lewin Day 5 Comments

There are plenty of SPI interface screens on the market, but few of them have the charm of the good old Nixie tube. [Tony] decided to whip up a simple three-Nixie module that could be addressed via SPI.

The stacked construction keeps things compact.

The module relies on a PIC16F15344 microcontroller to run the show, using its built-in SPI interface. It’s built with four stacked-up PCBs for ease of assembly and testing. It uses an internal buck converter to create the 170 volts required for the Nixie tubes from a 6 to 12 volt input. The high-voltage lines are routed towards the inside of the stack to minimize any nasty shocks when handling, though caution would still be advisable.

Driving the display is as simple as sending 16-bit words over the SPI interface, with the device operating in SPI client mode 1. If you’re looking for a simple way to have projects write output to a nice Nixie display, this module could be just what you’re looking for. Alternatively, if you can’t lay your hands on the tubes, there are other pretty solutions out there, too. Video after the break.

Continue reading “Nixie Display Module Is Addressable Via SPI” →

Is That A Typewriter In Your Pocket Or Are You Just Pleased To See Me?

December 2, 2022 by Dave Rowntree 16 Comments

Don’t have the right milling tool? Just make one!

[Attoparsec] wondered what if you could carry a typewriter in your pocket, then followed through with that and built one. (Video, embedded below.) Kind of. The plan was to use an existing set of striker bars, but not wanting to destroy a perfectly good typewriter, they realised that you can easily source just the bar set on eBay.

The first problem was that the striker bars are shaped to allow the typewriter mechanism to operate, but that would not make for a compact arrangement. After a spot of straightening in a big vice, and drilling in a custom jig, they were in a suitable state to be arranged inside the case. The casing is milled from a chunk of aluminium, complete with a nice recess to hold an ink-impregnated felt pad. To prevent this pad from drying out when stowed, and to keep the whole thing clear of pocket lint, a U-shaped metal cover was bent from some sheet. This slides into a set of slots that are milled near the edges, in a very satisfying manner. This last bit was causing them a little trouble, so a custom slotting tool was created especially for the job. And a good job was indeed done. The final results look as you might expect from a manual ‘typewriter’ quirky, a bit wonky, but fabulous all the same.

If you have an old typewriter that needs some attention, here’s a quick guide for giving it a once-over. Some of you of a certain age may remember electronic typewriters with some fondness. They died a rapid death, but if you’ve still got one lurking, you could convert it into a Linux terminal for some clackity nostalgic fun.

Continue reading “Is That A Typewriter In Your Pocket Or Are You Just Pleased To See Me?” →

A Dead Photographic Format Rises From The Ashes

December 2, 2022 by Jenny List 34 Comments

Sometimes we stumble upon a hack that’s not entirely new but which is still pretty exceptional. So it is with [Hèrm Hofmeyer]’s guide to recreating a film cartridge for the Kodak Disc photographic format. It’s written in 2020, but describing a project around a decade old.

The disc format was Kodak’s great hope in the 1980s, the ultimate in photographic convenience in which the film was a 16-shot circular disc in a thin cartridge. Though the cameras were at the consumer end of the market they were more sophisticated than met the eye, with the latest electronics for the time and some innovative plastic multi-element aspherical lenses. It failed in the face of better compact 35 mm cameras because the convenience of the disc wasn’t enough to make up for the relatively small negative and that few labs had the specialized printing equipment to get the best results from the format. The cameras faded from view, and the film ceased manufacture at the end of the 1990s.

The biggest hurdle to creating a Disc cartridge comes in the cartridge shells themselves. It’s solved by sourcing them second-hand from Film Rescue International, a specialist in developing expired photographic film. The stages follow the cutting of a film disc, perforating its edges, and fitting it into the cartridge. It’s an exact enough process in the pictures, and it’s worth remembering that in the real cartridges it must be done in the dark.

This is an interesting piece of work for anyone with an interest in photography, and while the Disc cameras were always a consumer snapshot camera we can see that it would appeal to those influenced by Lomography. We wish we could get our hands on a Disc cartridge, an maybe CAD up a 3D printable version to make it more accessible.

Interfacing An Old Engine Cowl Flaps Indicator To USB

November 29, 2022 by Dave Rowntree 9 Comments

[Glen Akins] had a WW2-era aircraft engine cowl flap indicator lying around (as you do) and thought it would make a jolly fine USB-attached indicator. The model in question is a General Electric model 8DJ4PBV DC Selsyn, which was intended for four-engined aircraft. For those not familiar with the purpose [Glen] explains in his detailed writeup, that piston-engine aircraft of that era were air-cooled, and during conditions of maximum engine power — such as during take-off — flaps on the side of the engine cowling could be opened to admit additional cooling airflow. These indicator dials were connected to a sender unit on each of the flap actuators, providing the pilots an indication of the flaps’ positions. Continue reading “Interfacing An Old Engine Cowl Flaps Indicator To USB” →

Jansen's linkage, paper model of a bar linkage

Making Paper Strandbeesten

November 25, 2022 by Anne Ogborn 15 Comments

We love the artistry of paper mechanisms. Simple tools and techniques creating humor, beauty, and amazement.

[Federico Tobon] from [Wolfcat Workshop] makes amazing automata, crosses between cut paper art, origami, and traditional carved wood automata. He’s put out a useful new video on making linkages in paper parts.

In this short video, [Federico] shows us how to make a paper version of the leg mechanism for [Theo Jansen]’s classic Strandbeest, which we’ve covered in many variations.

Rotating joints in paper automata are sometimes done with a mechanical fastener like a post screw, but it violates the simplicity of the affair and often looks clunky. [Federico] uses a simple self fastener. A 5 mm hole in one part mates with two “flaps” in the other part. He’s made a separate video covering how to make the fastenings. He’s using a paper crafter’s Cricut-type machine to cut the parts. Pretty cool.

We’ve covered lots of other cool stuf from [Wolfcat Workshop]. If you want more of his automata eye candy, check out Simple Automata Extravaganza.

A Commodore SX-64 showing a six-digit code and a countdown timer

Generating Two-Factor Authentication Codes With A Commodore 64

November 14, 2022 by Robin Kearey 15 Comments

If you’ve used a corporate VPN or an online-banking system in the past fifteen years or so, chances are you’ve got a few of those little authenticator key fobs lying around, still displaying a new code every 30 seconds. Today such one-time codes are typically sent to you by text message or generated by a dedicated smartphone app, which is convenient but a bit boring. If you miss having a dedicated piece of hardware for your login codes, then we’ve got good news for you: [Cameron Kaiser] has managed to turn a Commodore SX-64 into a two-factor authenticator. Unlike a key fob that’s one gadget you’re not likely to lose, and any thief would probably need to spend quite some time figuring out how to operate it. Continue reading “Generating Two-Factor Authentication Codes With A Commodore 64” →