Day: August 9, 2024

The Luminiferous Theremin

August 9, 2024 by 4 Comments

[Extreme Kits] asks the question: “What the hell is a luminiferous theremin?” We have to admit, we know what a thermin is, but that’s as far as we got. You’ve surely seen and heard a theremin, the musical instrument developed by Leon Theremin that makes swoopy music often associated with science fiction movies. The luminiferous variation is a similar instrument that uses modern time of flight sensors to pick up your hand positions.

The traditional instrument uses coils, and your hands alter the frequency of oscillators. Some versions use light sensors to avoid the problems associated with coils. While the time of flight sensors also use light, they are immune to many false readings caused by stray light.

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Laser Fault Injection On The Cheap

August 9, 2024 by 8 Comments

One can only imagine the wonders held within the crypto labs of organizations like the CIA or NSA. Therein must be machines of such sophistication that no electronic device could resist their attempts to defeat whatever security is baked into their silicon. Machines such as these no doubt bear price tags that only a no-questions-asked budget could support, making their techniques firmly out of reach of even the most ambitious home gamer.

That might be changing, though, with this $500 DIY laser fault injection setup. It comes to us from Finnish cybersecurity group [Fraktal], who have started a series of blog posts detailing how they built their open-source reverse-engineering rig. LFI is similar to other “glitching” attacks we’ve covered before, such as EMP fault injection, except that a laser shining directly on a silicon die is used to disrupt its operation rather than a burst of electromagnetic energy.

Since LFI requires shining the laser very precisely on nanometer-scale elements of a bare silicon die, nanopositioning is the biggest challenge. Rather than moving the device under attack, the [Fraktal] rig uses a modified laser galvanometer to scan an IR laser over the device. The galvo and the optical components are all easily available online, and they’ve started a repo to document the modifications needed and the code to tire everything together.

Of course, this technique requires the die in the device under study to be exposed, but [Fraktal] has made that pretty approachable too. They include instructions for milling away the epoxy from the lead-frame side of a chip, which is safer for the delicate structures etched into the top of the die. The laser can then shine directly through the die from the bottom. For “flip-chip” packages like BGAs, the same milling technique would be done from the top of the package. Either way, we can imagine a small CNC mill making the process safer and quicker, even though they seem to have done pretty well with a Dremel.

This looks like a fantastic reverse engineering tool, and we’re really looking forward to the rest of the story.
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The Waveguide Explanation You Wish You’d Had At School

August 9, 2024 by 13 Comments

Anyone who has done an electronic engineering qualification will at some point have had to get to grips with transmission lines, and then if they are really lucky, waveguides. Perhaps there should be one of those immutable Laws stating that for each step in learning about these essential parts, the level of the maths you are expected to learn goes up in an exponential curve, for it’s certainly true that most of us breathe a hefty sigh of relief when that particular course ends. It’s not impossible to understand waveguides though, and [Old Hack EE] is here to slice through the formulae with some straightforward explanations.

First of all we learn about the basics of propagation in a waveguide, then we look at the effects of dimension on frequency. Again, there’s little in the way of head-hurting maths, just real-world explanations of cutt-off frequencies, and of coupling techniques. For the first time we’ve seen, here are simple and understandable explanations of the different types of splitter, followed up by the famous Magic T. It’s all in the phase, this is exactly the stuff we wish we’d had at university.

The world needs more of this type of explanation, after all it’s rare to watch a YouTube video and gain an understanding of something once badly taught. Take a look, the video is below the break.

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The First Fitbit: Engineering And Industrial Design Lessons

August 9, 2024 by 7 Comments

It could happen to anyone of us: suddenly you got this inkling of an idea for a product that you think might just be pretty useful or even cool. Some of us then go on to develop a prototype and manage to get enough seed funding to begin the long and arduous journey to turn a sloppy prototype into a sleek, mass-produced product. This is basically the story of how the Fitbit came to be, with a pretty in-depth article by [Tekla S. Perry] in IEEE Spectrum covering the development process and the countless lessons learned along the way.

Of note was that this idea for an accelerometer-based activity tracker was not new in 2006, as a range of products already existed, from 1960s mechanical pedometers to 1990s medical sensors and the shoe-based Nike+ step tracker that used Apple’s iPod with a receiver. Where this idea for the Fitbit was new was that it’d target a wide audience with a small, convenient (and affordable) device. That also set them up for a major nightmare as the two inventors were plunged into the wonderfully terrifying world of industrial design and hardware development.

One thing that helped a lot was outsourcing what they could to skilled people and having solid seed funding. This left just many hardware decisions to make it as small as possible, as well as waterproof and low-power. The use of the ANT protocol instead of Bluetooth saved a lot of battery, but meant a base station was needed to connect to a PC. Making things waterproof required ultrasonic welding, but lack of antenna testing meant that a closed case had a massively reduced signal strength until a foam shim added some space. The external reset pin on the Fitbit for the base station had a low voltage on it all the time, which led to corrosion issues, and so on.

While much of this was standard development and testing  fun, the real challenge was in interpreting the data from the accelerometer. After all, what does a footstep look like to an accelerometer, and when is it just a pothole while travelling by car? Developing a good algorithm here took gathering a lot of real-world data using prototype hardware, which needed tweaking when later Fitbits moved from being clipped-on to being worn on the wrist. These days Fitbit is hardly the only game in town for fitness trackers, but you can definitely blame them for laying much of the groundwork for the countless options today.

500cc Of 4-Wheel Off-Road Fun

August 9, 2024 by 9 Comments

Who among us hasn’t at some point thought of building a little vehicle, and better still, a little off-road vehicle for a few high-octane rough-terrain adventures. [Made in Poland] has, and there he is in a new video with a little off-road buggy.

The video which we’ve paced below the break is quite long, and it’s one of those restful metalworking films in which we see the finished project take shape bit by bit. In this case the buggy has a tubular spaceframe, with front suspension taken from a scrap quad and a home-made solid rear axle. For power there’s a 500cc Suzuki two-cylinder motorcycle engine, with a very short chain drive from its gearbox to that axle. The controls are conventional up to a point, though we’d have probably gone for motorcycle style handlebars with a foot shift rather than the hand-grip shift.

The final machine is a pocket drift monster, and one we’d certainly like to have a play with. We’d prefer some roll-over protection and we wonder whether the handling might be improved were the engine sprung rather than being part of a huge swing-arm, but it doesn’t appear to interfere with the fun. If you fancy a go yourself it’s surprisingly affordable to make a small vehicle, just build a Hacky Racer.

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Hackaday Podcast Episode 283: Blinding Lasers, LEDs, And ETs

August 9, 2024 by 3 Comments

Hackaday Editors Elliot Williams and Al Williams reflect on the fact that, as humans, we have–at most–two eyes and no warp drives. While hacking might not be the world’s most dangerous hobby, you do get to work with dangerous voltages, temperatures, and frickin’ lasers. Light features prominently, as the guys talk about LED data interfaces, and detecting faster-than-light travel.

There’s also a USB sniffer, abusing hot glue, and some nostalgia topics ranging from CRT graphics to Apollo workstations (which have nothing directly to do with NASA). The can’t miss articles this week cover hacking you and how you make the red phone ring in the middle of a nuclear war.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

As always, please download the file to archive in your doomsday bunker.

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Custom Pneumatic Cylinders Lock This Monitor Arm In Place

August 9, 2024 by 8 Comments

Few consumer-grade PCs are what you’d categorize as built to last. Most office-grade machines are as likely as not to give up the ghost after ingesting a few too many dust bunnies, and the average laptop can barely handle a few drops of latte and some muffin crumbs before croaking. Sticking a machine like that in the shop, especially a metal shop, is pretty much a death sentence.

And yet, computers are so useful in the shop that [Lucas] from “Cranktown City” built this neat industrial-strength monitor arm. His design will look familiar to anyone with a swing-arm mic or desk light, although his home-brew parallelogram arm is far sturdier thanks to the weight of the monitor and sheet-metal enclosure it supports. All that weight exceeded the ability of the springs [Lucas] had on hand, which led to the most interesting aspect of the build — a pair of pneumatic locks. These were turned from a scrap of aluminum rod and an old flange-head bolt; when air pressure is applied, the bolt is drawn into the cylinder, which locks the arm in place. To make it easy to unlock the arm, a pneumatic solenoid releases the pressure on the system at the touch of a button. The video below has a full explanation and demonstration.

While we love the idea, there are a few potential problems with the design. The first is that this isn’t a fail-safe design, since pressure is needed to keep the arm locked. That means if the air pressure drops the arm could unlock, letting gravity do a number on your nice monitor. Second is the more serious problem [Lucas] alluded to when he mentioned not wanting to be in the line of fire of those locks should something fail and the piston comes flying out under pressure. That could be fixed with a slight design change to retain the piston in the event of a catastrophic failure.

Problems aside, this was a great build, and we always love [Lucas]’ seat-of-the-pants engineering and his obvious gift for fabrication, of which his wall-mount plasma cutter is a perfect example.

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