Gears Are Old And Busted, Capstans Are Cool

June 3, 2024 by 44 Comments

Zero backlash, high “gear” reduction, high torque transparency, silent operation, and low cost. What is this miracle speed reduction technology, you ask? Well, it’s shoelaces and a bunch of 3D printed plastic, at least in [Aaed Musa]’s latest installment in his series on developing his own robot dog.

OK, the shoelaces were only used in the first proof of concept. [Aaed] shortly upgrades to steel cable, and finds out that steel fatigues and snaps after a few hours. He settles on Dyneema DM-20, a flexible yet non-stretching synthetic rope.

Before it’s all over, he got a five-bar linkage plotting with a pencil on the table and a quadriped leg jumping up and down on the table — to failure. All in all, it points to a great future, and we can’t wait to see the dog-bot that’s going to come out of this.

There’s nothing secret about using capstan drives, but we often wonder why we don’t see cable-powered robotics used more in the hacker world. [Aaed] makes the case that it pairs better with 3D printing than gears, where the surface irregularities really bind. If you want to get a jumpstart, the test fixture that he’s using is available on GitHub.

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ATtiny85 Mouse Jiggler Lets You Take A Break

June 3, 2024 by 54 Comments

The good news is that more and more people are working from home these days. The bad news is that some of the more draconian employers out there aren’t too happy about it, to the point of using spyware software to keep tabs on their workers. Better make that bathroom break quick — Big Brother is watching!

One simple way to combat such efforts is a mouse jiggler, which does…well it does exactly what it sounds like. If you find yourself in need of such a device, the WorkerMouse from [Zane Bauman] is a simple open source design that can be put together with just a handful of components.

The WorkerMouse is designed to be assembled using through-hole parts on a scrap of perfboard, but you could certainly swap them out for their SMD variants if that’s what you have on hand. The circuit is largely made up out of passive components anyway, except for the ATtiny85 that’s running the show.

[Zane] decided to embrace modernity and couple the circuit with a USB-C breakout board, but naturally you could outfit it with whatever USB flavor you want so long as you’ve got a cable that will let you plug it into your computer.

The project’s C source code uses V-USB to connect to the computer and act as a USB Human Interface Device (HID). From there, it generates random speed and position data for a virtual mouse, and dumps it out every few seconds. The end result is a cursor that leaps around the screen whenever the WorkerMouse is plugged in, which should be enough to show you online while you step away from the computer. As an added bonus, [Zane] has put together a nice looking 3D printable enclosure for the board. After all, the thing is likely going to be sitting on your desk, might as well have it look professional.

If you’ve got the time to get a PCB made, you might also be interested in the MAUS we covered last year, which also keeps the ATtiny85 working so you don’t have to.

Aiken’s Secret Computing Machines

June 3, 2024 by 2 Comments

This neat video from the [Computer History Archives Project] documents the development of the Aiken Mark I through Mark IV computers. Partly shrouded in the secrecy of World War II and the Manhattan Project effort, the Mark I, “Harvard’s Robot Super Brain”, was built and donated by IBM, and marked their entry into what we would now call the computer industry.

Numerous computing luminaries used the Mark I, aside from its designer Howard Aiken. Grace Hopper, Richard Bloch, and even John von Neumann all used the machine. It was an electromechanical computer, using gears, punch tape, relays, and a five horsepower motor to keep it all running in sync. If you want to dig into how it actually worked, the deliciously named patent “Calculator” goes into some detail.

The video goes on to tell the story of Aiken’s various computers, the rift between Harvard and IBM, and the transition of computation from mechanical to electronic. If this is computer history that you don’t know, it’s well worth a watch. (And let us know if you also think that they’re using computer-generated speech to narrate it.)

If “modern” computer history is more your speed, check out this documentary about ENIAC.

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Intentionally Overly-Complex Clock Is Off To A Good Start

June 3, 2024 by 1 Comment

[Kelton] from Build Some Stuff decided to create a clock that not only had kinetic elements, but a healthy dose of Rube Goldberg inspiration. The result is a work in progress, but one that looks awfully promising.

The main elements of the design are rotating pieces that indicate the hours and minutes, but each hour is advanced solely by the satisfying physical culmination of multiple interacting systems. Those systems also completely reset themselves every hour.

Each hour, a marble run kicks off a short chain reaction that culminates in advancing the hour.

At the top of the hour, a marble starts down a track and eventually tips over a series of hinged “dominoes”, which culminate in triggering a spring-loaded ratchet that advances the hour. The marble then gets carried back to the top of the device, ready for next time. Meanwhile, the domino slats and spring-loaded ratchets all get reset by a pulley system.

There’s still some work to do in mounting the motor, pulley system, and marble run. Also, a few bugs have surfaced, like a slight overshoot in the hour display. All par for the course for a device with such a large number of moving parts, we suppose.

[Kelton] has a pretty good sense how it will all work in the end, and it looks promising. We can’t wait to see it in its final form, but the tour of clock so far is pretty neat. Check it out in the video, embedded just under the page break.

As for the clock’s inspiration, Rube Goldberg’s cultural impact is hard to overstate and our own Kristina Panos has an excellent article about the man that might just teach you something you didn’t know.

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Tech In Plain Sight: Theodolites

June 3, 2024 by 23 Comments

We take it for granted that you can look at your phone and tell exactly where you are. At least, as exact as the GPS satellites will allow. But throughout human history, there has been a tremendous desire to know where here is, exactly. Where does my farm end and yours start? Where is the border of my city or country? Suppose you have a flagpole directly in the center of town and a clock tower at the edge of town. You know where they are precisely on a map. You also know how tall they are. What you need is a theodolite, which is an instrument that measures angles very precisely.

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To the left, a breadboard with the ATMega328P being attacked. To the right, the project's display showing multiple ;) smiley faces, indicating that the attack has completed successfully.

Glitching An ATMega328P Has Never Been Simpler

June 3, 2024 by 4 Comments

Did you know just how easily you can glitch microcontrollers? It’s so easy, you really have no excuse for not having tried it out yet. Look, [lord feistel] is doing glitching attacks on an ATMega328P! All you need is an Arduino board with its few SMD capacitors removed or a bare 328P chip, a FET, and some sort of MCU to drive it. All of these are extremely generic components, and you can quickly breadboard them, following [lord feistel]’s guide on GitHub.

In the proof-of-concept, you can connect a HD44780 display to the chip, and have the victim MCU output digits onto the display in an infinite loop. Inside of the loop is a command to output a smiley face – but the command is never reachable, because the counter is reset in an if right before it. By glitching the ATMega’s power input, you can skip the if and witness the ;) on your display; it is that simple.

What are you waiting for? Breadboard it up and see for yourself, this might be the method that you hack your next device and make it do your bidding. If the FET-and-MCU glitching starts to fail you at some point, there’s fancier tools you can use, like the ChipWhisperer. As for practical examples, [scanlime]’s elegant glitching-powered firmware hack is hard to forget.

A Treasure Trove In An English Field

June 3, 2024 by 12 Comments

This is being written in a tent in a field in Herefordshire, one of the English counties that borders Wales. It’s the site of Electromagnetic Field, this year’s large European hacker camp, and outside my tent the sky is lit by a laser light show to the sound of electronic music. I’m home.

One of the many fun parts of EMF is its swap table. A gazebo to which you can bring your junk, and from which you can take away other people’s junk. It’s an irresistible destination which turns a casual walk into half an hour pawing through the mess in search of treasure, and along the way it provides an interesting insight into technological progress. What is considered junk in 2024?

Something for everyone

As always, the items on offer range from universal treasures of the I-can’t-believe-they-put that-there variety, through this-is-treasure-to-someone-I’m-sure items, to absolute junk. Some things pass around the camp like legends; I wasn’t there when someone dropped off a box of LED panels for example, but I’ve heard the story relayed in hushed tones several times since, and even seen some of the precious haul. A friend snagged a still-current AMD processor and some Noctua server fans as another example, and I’m told that amazingly someone deposited a Playstation 5. But these are the exceptions, in most cases the junk is either very specific to something, or much more mundane. I saw someone snag an audio effects unit that may or may not work, and there are PC expansion cards and outdated memory modules aplenty.

Finally, there is the absolute junk, which some might even call e-waste but I’ll be a little more charitable about. Mains cables, VGA cables, and outdated computer books. Need to learn about some 1990s web technology? We’ve got you covered. Continue reading “A Treasure Trove In An English Field” →