Hollow State Memory

October 26, 2017 by Al Williams 12 Comments

A lot of people like tubes either for their audio sound or their collectible value. [Uniservo] likes oddball tubes. His recent video (see below) shows a radechon — a computer memory tube. These were apparently widely used in RADAR sets until recently and has some similarity to a Williams tube.

The tube is essentially a CRT that illuminates a sheet of mica or another dielectric instead of a phosphor screen. The dielectric has a fine mesh grid in contact with it. By depositing charge on the mica, the tube can store an analog value. In theory, the tube could store about 16 kbits of information, but in practice, the resolution was less.

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Reconstructing A Blurry QR Code

October 26, 2017 by Lewin Day 4 Comments

QR Codes are a two-dimensional type of matrix barcode that are used for a variety of uses. They’re one way of turning a long piece of string data into an easily machine-readable format. For this reason, they can be used to store private keys for encryption and crypto-currency purposes. [Roger Ver] attempted to use a QR code containing a private key to give away some cryptocurrency on TV, but the code was blurred out by the broadcaster. Not ones to give up easily, [Michael] and [Clément] decided to see if they could reconstruct it anyway.

The work begins, as so many cryptographic exploits do, with the collection of as much of the plaintext key as possible. By stepping through the footage frame by frame, small pieces of the unobscured QR code were found, as well as some of the private key itself. By combining this with enhanced images of the blurred code, the team were able to put together less than one third of the QR code. The team had other tricks up their sleeve though – they knew the QR contained a private key of a particular format, and were able to figure out the QR code was 41×41 pixels.

By using this data along with a careful study of the QR code format, the team were able to put together some code in Python to brute force the key. After 838849 trials, the key was found, and the team were able to claim the prize. It’s a great example of cryptographic analysis – and so is this story on hacking your own password.

[Thanks to Esko for the tip!]

Restoring A Tonka Truck With Science

October 26, 2017 by Tom Nardi 36 Comments

The yellow Tonka Truck. Instantly recognizable by any child of decades past, that big metal beast would always make you popular around the sandbox. There were no blinking lights to dazzle, no noises to be heard (unless you count the hard plastic wheels rolling on concrete), even the dumping action is completely manual. But back then, it was a possession to be treasured indeed.

So it’s perhaps no surprise that there is a certain following for these classic trucks today, though like with most other collectibles, a specimen in good condition can be prohibitively expensive. The truck that [PoppaFixIt] found in the trash was certainly not one of those specimens, but with some patience and knowledge of basic chemistry, he was able to bring this vintage toy back to the present.

The first step was to disassemble the truck. Before they switched over to Chinese mass production, these trucks were built with actual rivets. After drilling them out and unfolding the little metal tabs that toy makers loved back in the day, he was able to separate the metal body of the truck from the plastic detail bits. The plastic parts just needed a fresh coat of paint, but the rusted metal body would need a bit more attention.

Remembering a tip he read online, [PoppaFixIt] decided to attempt electrolytic rust removal to get the metal parts back into serviceable condition. A big plastic bin, some washing soda, and old steel window weights for his sacrificial anodes was all the equipment he needed for the electrolysis tank. To power the chemical reaction he used a standard 12 volt car battery and charger wired in parallel; this step is important, as he notes most newer chargers are smart enough not to work unless they see a real battery connected.

After running the setup overnight, the collected rust and junk on the window weights was proof enough the process worked. From there, it was just a fresh coat of yellow paint, a new sticker kit from eBay, and his Tonka truck was ready to face another 30+ years of service.

If you’re looking to restore things larger than a child’s toy, you may be interested in the much larger electrolytic setup we’ve covered previously. Of course if you’re really pressed for time, you could try blasting the rust away with a laser.

Imperial Rocker For Stopping Tiny Rebel Scum

October 25, 2017 by Tom Nardi 15 Comments

Some of the luckiest kids in the world have to be the ones with hackers and makers as parents. While normal kids are stuck playing with cookie cutter mass produced toys, these kids get one-off gadgets and creations that will be the envy of the playground. Frankly, some of the stuff ends up being so cool that it’ll get the adults wishing they could go back in time and play with it.

One such parent, and one such project, is the Imperial Rocker by [Matthew Regonini]. Hoping to instill an obsession with a galaxy far, far, away on his offspring, [Matthew] designed this AT-AT rocking horse piece by piece in Illustrator, and then cut it all out of birch using his XCarve CNC router. Each piece was then meticulously glued together to produce a final 3D effect from the individual cutouts.

With a liberal application of spring clamps to hold it all together while it dried, all that was left to do was painstakingly sand all the parts so the edges of the laminated construction would be smooth. Dowels were then added for the handlebars and foot pegs, and a few coats of polyurethane seal up the plywood while bringing out a natural look.

[Matthew] notes some issues here and there, notably quite a bit of blowout in some of the detail cuts and a couple miscalculated dimensions. But he reasons that the rocker is going to live a pretty hard life anyway, so best not to sweat the small stuff.

While the Imperial Rocker has that quaint old-school charm, we wonder how long it will be before [Matthew’s] little Stormtrooper starts yearning for the blinking lights and buttons that youngsters just can’t get enough of.

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Reverse Polish Notation And Its Mildly Confusing Elegance

October 24, 2017 by Jenny List 131 Comments

The best rummage sale purchase I ever made was a piece of hardware that used Reverse Polish Notation. I know what you’re thinking… RPN sounds like a sales gimmick and I got taken for a fool. But I assure you it’s not only real, but a true gem in the evolution of computing.

Sometime in the 1980s when I was a spotty teen, I picked up a calculator at a rummage sale. Protected by a smart plastic case, it was a pretty good condition Sinclair Scientific that turned out when I got it home to have 1975 date codes on its chips, and since anything with a Sinclair badge was worth having it became mine for a trifling amount of money. It had a set of corroded batteries that had damaged one of its terminals, but with the application of a bit of copper strip I had a working calculator.

And what a calculator! It didn’t have many buttons at a time when you judged how cool a scientific calculator was by the prolific nature of its keyboard. This one looked more akin to a run-of-the-mill arithmetic calculator, but had button modes for trigonometric functions and oddly an enter key rather than an equals sign. The handy sticker inside the case explained the mystery, this machine used so-called Reverse Polish Notation, or RPN. It spent several years on my bench before being reverently placed in a storage box of Sinclair curios which I’ve spent half a day turning the house over to find as I write this article.

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Are Microwave Guns For Real?

October 23, 2017 by Lewin Day 65 Comments

Almost exactly one year ago, [Kreosan] published a video detailing an EM “weapon” built out of three magnetrons, some batteries, and a taser. It all seemed a bit too good to be true, so [Allen] decided to try and replicate the results for himself.

[Kreosan]’s original video was impressive, showing everything from home stereos to a humble moped exploding when in the presence of their powerful device. However, many of those watching the video doubted the footage. Most criticism centered around the nature of the power supply to the magnetron falling short of the usual 700-1000W seen in a microwave oven.

Initial testing with a single magnetron. This setup could light the bulb at a distance of a few centimeters.

[Allen] starts by experimenting with a single magnetron, successfully using it to light a compact fluorescent bulb at a range of a few centimeters. Scaling up to the full triple magnetron setup with a cardboard and foil feedhorn, [Allen] is, at best, able to crash a calculator at a distance of a few feet.

The microwaves cause no explosions, and the device doesn’t seem to have anywhere near the 50-foot range claimed by [Kreosan] for their device. [Allen] puts forth the theory that the explosions seen in the original footage are far more likely to be from small firecrackers rather than any electronic components dying from microwaves.

Overall it’s a solid attempt to recreate someone else’s work to verify the results, a cornerstone of science. We did bristle somewhat at the valiant 18650 being described as a “vape battery”, however. For more microwave goodness, check out this attempt to recreate the TSA’s body scanners .

SegaPi Zero Shows Game Gear Some Respect

October 21, 2017 by Tom Nardi 15 Comments

If you were a gamer in 1991, you were presented with what seemed like an easy enough choice: you could get a Nintendo Game Boy, the gray brick with a slightly nauseating green-tinted screen that was already a couple of years old, or you could get yourself a glorious new Sega Game Gear. With full color display and games that were ported straight from Sega’s home consoles, it seemed like the Game Gear was the true future of portable gaming. But of course, that’s not how things actually went. In reality, technical issues like abysmal battery life held the Game Gear back, and conversely Nintendo and their partners were able to squeeze so much entertainment out of the Game Boy that they didn’t even bother creating a true successor for it until nearly a decade after its release.

While the Game Gear was a commercial failure compared to the Game Boy back in the 1990s and never got an official successor, it’s interesting to think of what may have been. A hypothetical follow-up to the Game Gear was the inspiration for the SegaPi Zeo created by [Halakor]. Featuring rechargeable batteries, more face buttons, and a “console” mode where you can connect it to a TV, it plays to the original Game Gear’s strengths and improves on its weaknesses.

As the name implies the SegaPi Zero is powered by the Raspberry Pi Zero, and an Arduino Pro Micro handles user input by tactile switches mounted behind all the face buttons. A TP4056 charging module and step-up converter are also hiding in there, which take care of the six 3.7 lithium-Ion 14500 batteries nestled into the original battery compartments. With a total capacity of roughly 4,500 mAh, the SegaPi Zero should be able to improve upon the 3 – 4 hour battery life that helped doom the original version.