Retrotechtacular: The Cryotron Computer


Have you ever heard of a Cryotron Computer before? Of course not. Silicon killed the radio star: this is a story of competing technologies back in the day. The hand above holds the two competitors, the bulkiest one is obviously the vacuum tube, and the three-legged device is what became a household name. But to the right of that tube is another technological marvel that can also be combined into computing machines: the cryotron.

[Dudley Allen Buck] and his contributions to early computing are a tale of the possible alternate universe that could have been cryotrons instead of silicon transistors. Early on we find that the theory points to exotic superconductive materials, but we were delighted to find that in the conception and testing stages [Buck] was hacking. He made his first experimental electronic switches using dissimilar metals and dunking them in liquid helium. The devices were copper wire wrapped around a tantalum wire. The tantalum is the circuit path, the copper wire acts as the switch via a magnetic field that alters the resistance of the tantalum.

The name comes from the low temperature bath necessary to make the switches work properly. Miniaturization was the key as it always is; the example above is a relatively small example of the wire-wound version of the Cryotron, but the end goal was a process very familiar to us today. [Buck] was searching for the thin film fabrication techniques that would let him shoe horn 75,000 or more into one single computing platform. Guess who came knocking on his door during this period of his career? The NSA. The story gets even more interesting from there, but lest we rewrite the article we leave you with this: the technology may beat out silicon in the end. Currently it’s one of the cool kids on the block for those companies racing to the quantum computing finish line.

[Thanks Frederick]

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

Retrotechtacular: The Magic of Making Cars in the ’30s


We usually shy away from calling things ‘magic’ in our features because, you know… science. But in the case of this Chevrolet manufacturing reel from 1936 the presentation is nothing short of an industrialized version of The Sorcerer’s Apprentice. Well, not in the sense of mischief, but in that there is almost no explanation and the way the footage is laced together you get the strong feeling that, at the time, this type of industrialization was magic; a modern marvel. The techniques and skills of each worked passed down from a master to an apprentice but virtually unknown to the general public.

The clip, which is also embedded below, starts off in the machine shop where mold makers are getting ready to go into assembly line production. From there it’s off to the foundry for part casting and then into the stamping plant where white-hot (perhaps red-hot, but black and white film) metal is shaped by man-mangling presses. The image above follows the cast, stamped, and machined parts onto the assembly line. We like seeing a room full of pistons being QA checked by hand using a width gauge and micrometer.  The film continues through to the finished vehicle and we think you’ll agree there’s more than enough voyeuristic video here to overcome that lack of narration.

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Retrotechtacular: Breaking Atoms to Break the Ice


This documentary from 1959 gives a satisfyingly thorough look inside a nuclear powered icebreaking ship called Lenin. This actually set a couple of world’s-firsts: it was the first nuclear powered surface vessel and the first civilian vessel to be powered thusly.

The ship was built to clear shipping paths to the northern ports of Russia. Testing of both ice and models of the ship design point to the ability to break ice layers that are two meters thick. This requires a lot of power as ice-breakers generally use their hull shape and gravity to break the ice by driving up onto it to bend the ice to the breaking point. The Lenin achieved this power using its nuclear reactor to heat steam which drove electric generators. The energy produced drove three screws to power the vessel.

Of course this was back in the day when control panels were substantial, which you can get a peek at starting half-way through the twenty-minute film. This includes a demonstration of the ship’s network of radiation sensors which alert the control room, and sound a local alarm when they are triggered. During it’s 30-year operational life the vessel had a couple of accidents stemming from refueling operations. You can find more on that over at the Wikipedia page, but stick with us after the jump to see the vintage reel.

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Retrotechtacular: Shedding Light on Holograms

This week’s Retrotechtacular is a 1972 introduction to holography produced by the fine folks at Encyclopædia Britannica. It details quite admirably what holograms are and how they’re made.

Holograms are quite different from photographs, though both are recorded on film. Holography is based on the additive effects of waves: two crests of equal amplitude create a larger crest, while a crest and a trough of equal amplitude cancel each other out, causing an interference effect. The video demonstrates the concept nicely with water ripples and explains that the same effect happens with sound waves and light waves.

Lasers are the key to the intense and spectrally pure light required for holography. Incandescent light consists of too many wavelengths to be effectively split into two identical light wave sources. To create a hologram, a laser is split with an optical device into two beams. One beam is focused directly on the object being recorded and is called the object beam. The second beam is directed away from the scene through a series of mirrors and shone directly onto a film emulsion.

The film records the interference between the waves of the two beams. It appears to be blank after development, but upon close inspection reveals stripes of light and dark. When the exposed film is placed in the path of only the reference beam, the interference patterns recorded on the film split the beam back into two, recreating the scene. With the aid of a screen for projection, the hologram can be seen showing the original object in 2D. Another big difference between photographs and holograms is that even a small portion of a hologram can reproduce the entire scene, but a piece of a photograph is just that.

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Retrotechtacular: Lighting the Way for Talkie Pictures with Optical Sound Recording

This week’s Retrotechtacular is a 1943 Encyclopædia Britannica film focusing on optical sound reproduction for motion pictures. Both the sound and the images are recorded on film, which is only affected by light. Therefore, the sound waves must be converted to changes in light.

This is done the way you might expect: the sound waves hit a microphone and the changes in current are amplified and used to control the intensity of light falling on the film. Three types of soundtracks are described and wonderfully demonstrated at the end of the film.

All three types are made from a series of thin bars of light, and the corresponding current value is represented by changes in either their length or their width. In the Unilateral Variable Area recording, the bars extend from the right side of the sound track. Bilateral Variable Area recorded bars emanate uniformly toward the edges from the center. In Variable Density recording, all of the bars extend from the left to right extremes, but their thickness varies.

Variable Density recording is done with a light valve, which contains a pair of delicate metallic ribbons in a magnetic field that move like shutters when the sound current flows through them. The light coming through to the film is varied by the slot created in the space between the ribbons. The light patterns are changed back to sound through a photoelectric cell, which converts the variations in light back to changing current. These changes are amplified and run through a loudspeaker. Be sure to watch to the end to catch a demonstration of the recording methods, set to what we’re pretty sure is Camille Saint-Saëns’ Danse Macabre.

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Retrotechtacular: Hacking Mother Nature’s North Temperate Regions

…because they’ll tickle your insides! Seriously, don’t eat them if you happen to parachute alone into wilderness and must survive without firearms or equipment like our protagonist here. This 1955 US Navy-produced gem of a training film will show you how to recognize, procure, and prepare many kinds of nutritious plant, insect, and animal life commonly found between 45° and 70° north latitude.

While you hone your large game hunting skills, you can tide yourself over with all kinds of things that will just sit there ready to be plucked for your nourishment: many berries and fruits, nuts, moss, lichens, and the inner bark of several kinds of trees is edible. Sate your taste for savory with grubs, termites, or grasshoppers. When in doubt, eat what the birds and small animals are eating, but stay away from mushrooms. It’s too hard to distinguish the poisonous varieties.

Many edible things are found in and around bodies of water. Game such as deer, ducks, and birds are attracted to water and make their homes near it. Various kinds of traps made from twigs and vegetation will outwit rabbits and squirrels. You can fashion a bow and arrow in order to kill large quadrupeds like deer, elk, and ram. It’s best to aim for the head, neck, or just behind the shoulders as these are the most vulnerable areas.

Once you have killed a large animal, prepare it for cooking by draining its blood and removing its entrails. There are many ways to cook your spoils of survival, and most of them involve cutting the meat into small pieces first. Hopefully, you have some basic tools for starting fires.

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Retrotechtacular: Restoring A 19th Century Automaton


Made sometime in the 1790s or 1800s London, the Maillardet Automaton has a long and storied history. It was exhibited around England for several decades, brought over the Atlantic by [P.T. Barnum], nearly destroyed in a fire, and donated to the Franklin Institute in Philadelphia in the 1920s. From there, this amazingly complex amalgam of cogs, cams, and linkages eventually became the inspiration for the book – and movie - Hugo. Time hasn’t exactly been kind to this marvel of the clockmaker’s art; it has been repaired four times before receiving a complete overhaul in 2007 by [Andrew Baron].

[Fran], one of Hackaday’s sources for awesome projects, recently visited the Franklin Institute and posted a series of videos on the reverse engineering of the Maillardet Automaton. Being nearly destroyed and repaired so many times didn’t make this an easy job; it’s extremely possible no one alive has ever seen the eyes of the Automaton move as originally designed.

Even though the Maillardet Automaton has one of the largest series of cams of any mechanical draftsman, that doesn’t mean it’s simply an enlargement of an earlier machine. The automaton’s pen is like no other writing device on Earth, with a stylus acting as a valve to dispense ink whenever the tip touches paper. The eyes have linkages to follow the pen as it traces a drawing. In 1800, this automaton would have been a singularity in the uncanny valley, and watching it put pen to paper is still a little creepy today.

Below you’ll find a video from [Fran] demonstrating all seven drawings the Maillardet Automaton can reproduce. You can also find a whole bunch of pics of the mechanisms along with the 2007 repair report on [Andrew Baron]‘s site.

Retrotechtacular is a weekly column featuring hacks, technology, and kitsch from ages of yore. Help keep it fresh by sending in your ideas for future installments.

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