Retrotechtacular: Electronic Publishing In The 1930s

We are living in the age of citizen journalism and the 24-hour news cycle. Reports about almost anything newsworthy can be had from many perspectives, both vetted and amateur. Just a few decades ago, people relied on daily newspapers, radio, and word of mouth for their news. On the brink of the television age, several radio stations in the United States participated in an experiment to broadcast news over radio waves. But this was no ordinary transmission. At the other end, a new type of receiver printed out news stories, line drawings, and pictures on a long roll of paper.

Radio facsimile newspaper technology was introduced to the public at the 1939 World’s Fair at two different booths. One belonged to an inventor named William Finch, and one to RCA. Finch had recently made a name for himself with his talking newspaper, which embedded audio into a standard newspaper in the form of wavy lines along the edges that were read by a special device.

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Finally, A Working Lightsaber!

Just in time for the movie of the decade, [Allen] from [Sufficiently Advanced] has built a real working fire-based light saber. And it’s awesome.

He started out with a replica light saber and designed his own 3D printed enclosure to house a small tank with a syringe valve that goes inside the handle. This allows him to fuel it with a mixture of methanol and acetone, using butane as a propellant. He learned how to do this from [Tesla Down Under], who has some fantastic projects — most notably, flamethrowers.

A nichrome coil provides ignition for the flame, and after he got the pressure just right, it produces a pretty awesome, albeit skinny, flame-saber.

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Neil Movva: Adding (wearable) Haptic Feedback To Your Project

[Neil Movva] is not your average college student. Rather than studying for exams or preparing to defend a dissertation, he’s working on a project that will directly help the disabled. The project is Pathfinder, a wearable haptic navigation system for the blind. Pathfinder is an ambitious project, making it all the way to the semifinals of the 2015 Hackaday Prize. Haptics, the technology of providing feedback to a user through touch, lies at the core of Pathfinder. [Neil] was kind enough to present this talk about it at the Hackaday SuperConference.

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Calculus Is Not Hard – The Derivative

The Calculus is made up of a few basic principles that anyone can understand. If looked at in the right way, it’s easy to apply these principles to the world around you and to see how the real world works in their terms. Of the two main ideas of The Calculus — the derivative and the integral — today we’ll focus on the derivative.

You can enjoy this article by itself, but it is also worth looking back at the previous installment in this series. We went over the history of The Calculus and saw how it arose from two paradoxes put forth by a 4th century philosopher named Zeno of Elea. These paradoxes lead to the derivative/integral ideas that revolutionized mankind’s understanding of motion.

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Let’s Blow Up An Explosive Lightning Arrestor

Lightning is some nasty stuff. Luckily, it doesn’t have a very long lifespan. [BigClive] decided to tear down an 11KV lighting arrestor used in power distribution systems. The fiberglass core has silicone rubber water-shedding disks that make the unit look sort of floppy, but inside is some serious hardware.

To protect the circuit, metal oxide varistors shunt high voltage from a lightning strike to ground as you’d expect. The interesting part is how the device deals with failure. It would be a disaster if the device shorted the 11KV power line to ground for any length of time due to a fault. To prevent that problem, a resistor heats up when struck by lightning and triggers an explosive charge that disconnects the ground wire and releases a flag to indicate the failure.

[BigClive] triggered the charge in the video below. So if you like to see things explode in a bucket of water, you’ll enjoy the video.

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The Scientific Implausibility Of Starkiller Base

This post contains spoilers for Star Wars: The Force Awakens. These spoilers won’t affect you if you haven’t seen the movie; they’re equivalent to saying, “in A New Hope there’s a moon sized battle station with a superlaser” and “someone gets a hand amputated with a lightsaber in a Star Wars movie”


A lot has happened in the Star Wars universe since the battle of Endor. The Empire is in ruins, and Yavin 5 and the forest moon of Endor both have new planetary ring systems. The Rebellion has given way to a new Galactic Republic, but there is a spectre of evil looming in the unknown areas of the galaxy: the First Order, a malevolent force that has built a planet-sized superweapon capable of destroying entire planetary systems from across the galaxy. The Starkiller gets its energy from harvesting entire suns, moving from one solar system to another to feed this massive weapon of terror.

We’ve had nearly forty years to argue the plausibility of the Death Star, lightsabers, parsecs as a unit of time, and hyperdrives. It’s time to pass the hallowed tradition of arguing over fictional spacecraft to a new generation. Starkiller Base is a cool idea, but does the science behind it hold up? No. It’s completely implausible. It makes for a great story, but it’s completely implausible.

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Homemade Internal Combustion Engine – Sans Machine Shop

We’ve got a question for you:  If you were stuck in a basement, with nothing too much more than some copper pipe, solder, JB-Weld, and a few hand tools, do you think you could make a working 2-stroke motor? Well, [Makerj101] did just that, and the results are fan-freaking-tastic.

[Makerj101] began his journey like most of us do – with a full face-plant type failure. His first attempted at building an internal combustion engine wouldn’t run, due to a low compression ratio, and too small port sizes. So he did what most of us would do, and tore apart a small gas-power weed-whacker motor to see what he was doing wrong.

The type of engine he’s making is a 2-stroke. That makes the design much simpler as there are no mechanically controlled valves a like 4-stroke motor. The piston (along with the cylinder wall) does double duty by also directing the intake and exhaust gasses – along with a simple flap-type check valve.

For now, the ignition system is run off of mains power, but he has plans to change that – creating a self contained engine. We’re amazed that the entire build is made with such simple tools. Even the the piston is cast out of “JB Weld” epoxy putty. After seeing this, we think that the kid who took apart a clock is going to have to up his game a bit.

We’ve included all 6 parts after the break.

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