Leaking Data By Ultrasound

Human ears are capable of perceiving frequencies from roughly 20 Hz up to 20 kHz, at least when new. Correspondingly, our audio hardware is designed more or less to target these frequencies. However, there’s often a little extra capability at the upper edges, which [Jacek] shows can be exploited to exfiltrate data.

The hack takes advantage of the fact that most computers can run their soundcards at a sample rate of up to 48 kHz, which thanks to the Nyquist theorem means they can output frequencies up to around 24 kHz — still outside the range of human hearing. Computers and laptops often use small speaker drivers too, which are able to readily generate sound at this frequency. Through the use of a simple Linux shell script, [Jacek] is able to have a laptop output Morse code over ultrasound, and pick it up with nothing more than a laptop’s internal microphone at up to 20 meters away.

[Jacek] enjoys exploring alternative data exfiltration methods; he’s previously experimented with Ethernet leaks on the Raspberry Pi. Of course, with any airgap attack, the real challenge is often getting the remote machine to run the exfiltration script when there’s no existing remote admin access to be had. Video after the break.

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Killing Mosquitoes With Cardi B

Keeping a bird bath or a pond in your yard is a great way to add ambiance and style, but both of these things can be a haven for mosquitoes. Popular methods of getting rid of them are often with harsh pesticides, but [Shane] has brought us a more environmentally-friendly way of taking care of these disease-carrying insects by looping a Cardi B playlist underwater, killing the mosquito larvae.

While the build does include some other favorites such as “Baby Shark” and would probably work with any song (or audio of sufficient volume) the build is still pretty interesting. It’s based on a 555 timer circuit which powered an ultrasonic sound gun, but was repurposed for this build. The ultrasonic modules were replaced with piezo modules which were waterproofed with silicone. The sound produced vibrates at a frequency which resonates with the mosquito larvae and is fatal to them. [Shane] put the build into a small boat which can be floated in any pond, bird bath, horse trough, or water feature.

The major caveat to this build is that it may be damaging to other beneficial animals such as fish or frogs, so he suggests limiting its use to uninhabited stagnant water. Either way, though, it’s a pretty unique way of taking care of a mosquito problem not unlike another build which takes care of these insects in water a slightly different way.

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Giving Micro Channel Bus Computers A Sound Blaster Bark

Not many people today probably remember what ‘Micro Channel Architecture’ was about, though its acronym ‘MCA’ might ring a bell. Created by IBM to replace ISA (Industry Standard Architecture) and presumably claw back some of that sweet, sweet licensing money, it didn’t quite pan out as IBM hoped. As history shows us, PCI ended up replacing MCA in all of IBM’s systems. The IBM PS/2 systems that used MCA didn’t miss out on classic 1990s cards, such as the original Sound Blaster, but today MCA versions of the Sound Blaster are admittedly rather… rare, not to mention expensive.

But, no longer: decades after the last PS/2 users have moved on, [Tube Time] proudly presents the Snark Barker MCA. It’s a fully Sound Blaster compatible sound card. It supports AdLib synthesis, digital sound playback and recording, as well as a joystick input and MIDI. Based around a Xilinx XC9572XL CPLD and featuring what looks like a full-length MCA card, it would have made an original Sound Blaster card proud.

The GitHub repository not only contains the schematics, BOM and Verilog-based HDL for the CPLD, but also extensive documentation on the assembly and programming. As a bonus, there’s a troubleshooting section which covers some of the joys that came with the sloppy implementations of MCA across systems. Definitely worth a read.

If anyone decides to build this project and use it in their IBM PS/2 system, we would love to hear about it.

Of course, if all you need is a garden variety PCI Sound Blaster clone, the original Snark Barker is the way to go.

(Thanks, Darry)

Cardboard Models Trace Design Process Of Vintage Tektronix Miniscopes

There aren’t many brands that inspire the kind of passion and fervency among its customers as Tektronix does. The venerable Oregon-based manufacturer of top-end test equipment has produced more collectible gear over the last 75 years than just about anyone else.

Over that time they have had plenty of innovations, and in the 1970s they started looking into miniaturizing their flagship oscilloscopes. The vintageTEK museum, run by current and former employees, has a review of the design process of the 200 series of portable oscilloscopes that’s really interesting. At a time when scopes were portable in the way a packed suitcase is portable, making a useful instrument in a pocketable form factor was quite a challenge — even for big pockets.

The article goes into great detail on the back-and-forth between the industrial designers, with their endless stream of models, and the engineers who would actually have to stuff a working scope into whatever case they came up with. The models from the museum’s collection are wonderful bits of history and show where the industrial designers really pushed for some innovative designs.

Some of the models are clearly derived from the design of the big bench scopes, but some have innovative flip-down covers and other interesting elements that never made it to production. Most of the models are cardboard, but some were made of aluminum in the machine shop and sport the familiar “Tek blue” livery. But the pièce de résistance of the collection is a working engineering model of what would become the 200-series of miniscopes, a handmade prototype with a tiny round CRT and crudely labeled controls.

The vintageTEK museum sounds like another bucket-list stop for computer and technology history buffs. Tek has been doing things their own way for a long time, and stopping by the museum is sure to be a treat.

Thanks to [Tanner Bass] for the tip.

ISASTM Runs Vintage Cards Over USB

The ISA bus is a relic of the distant past, and no longer supported by the PC mainstream. Outside of retro fanatics and likely some long-term industrial users, it’s all but forgotten. That hasn’t stopped [Manawyrm] from hacking away, however, and she’s developed a nifty adapter for the modern era.

Still in its early stages of development, the ISASTM is a ISA-over-USB adapter that allows a modern computer to work with older expansion cards. Running on an STM32H743, and using the microcontroller’s native USB1 interface, the ISASTM card is able to be slotted into a backplane in order to address multiple cards with one adapter. [Manawyrm] demonstrates the hardware by running Monkey Island 1 in the PCem emulator, with sound provided by an AdLib ISA soundcard.

There are some throughput issues, which [Manawyrm] aims to solve by switching to USB2 and making some tweaks and improvements to the code. Regardless, it’s an impressive tool that we imagine could have some use in keeping some legacy hardware alive, too. Incidentally, it’s been a long while since we’ve seen a solid ISA hack around these parts. Video after the break.

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Axe Hacks: New Sounds For Your Electric Guitar Beginning From What Makes Them Tick

Creating music is a perfect hobby for anyone into hacking, and the amount of musical hacks and self-made instruments we come across here makes that supremely evident. It’s just a great match: you can either go full-on into engineering mode as music is in the end “just” applied physics, or simply ignore all of the theory and take an artistic approach by simply doing whatever feels right. The sweet spot is of course somewhere in between — a solid grasp of some music theory fundamentals won’t hurt, but too much overthinking eventually will.

The obvious choice to combine a favorite pastime like electronics or programming with creating music would be in the realm of electronic music, and as compelling as building synthesizers sounds, I’ll be going for the next best thing instead: the electric guitar. Despite its general popularity, the enormous potential that lies within the electric guitar is rarely fully utilized. Everyone seems to just focus on amp settings and effect pedals when looking for that special or unique sound, while the guitar itself is seen as this immutable object bestowed on us by the universe with all its predestined, magical characteristics. Toggle a pickup switch, and if we’re feeling extra perky, give that tone pot a little spin, that’s all there is to it.

The thing is, the guitar’s electrical setup — or wiring — in its stock form simply is as boring and generic as it can get. Sure, it’s a safe choice that does the job well enough, but there’s this entirely different world of tonal variety and individual controllability locked inside of it, and all it really takes is a screwdriver and soldering iron to release it. Plus, this might serve as an interesting application area to dive into simple analog electronics, so even if guitars aren’t your thing yet, maybe this will tickle your creativity bone. And if bass is more your thing, well, let me be ignorant and declare that a bass is just a longer guitar with thicker, lower-tuned strings, meaning everything that follows pretty much applies to bass as well, even if I talk about guitars.

However, in order to modify something, it helps to understand how it functions. So today, we’ll only focus on the basics of an electric guitar, i.e. what’s inside them and what defines and affects their tone. But don’t worry, once we have the fundamentals covered, we’ll be all settled to get to the juicy bits next time.

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Arduino Takes Control Of Dead Business Card Cutter

It’s a common enough situation, that when an older piece of equipment dies, and nobody wants to spend the money to repair it. Why fix the old one, when the newer version with all the latest bells and whistles isn’t much more expensive? We all understand the decision from a business standpoint, but as hackers, it always feels a bit wrong.

Which is exactly why [tommycoolman] decided to rebuild the office’s recently deceased Duplo CC-330 heavy duty business card cutter. It sounds like nobody really knows what happened to the machine in the first place, but since the majority of the internals were cooked, some kind of power surge seems likely. Whatever the reason, almost none of the original electronics were reused. From the buttons on the front panel to the motor drivers, everything has been implemented from scratch.

An Arduino Mega 2560 clone is used to control four TB6600 stepper motor drivers, with a common OLED display module installed where the original display went. The keypad next to the screen has been replaced with 10 arcade-style buttons soldered to a scrap of perfboard, though in the end [tommycoolman] covers them with a very professional looking printed vinyl sheet. There’s also a 24 V power supply onboard, with the expected assortment of step up and step down converters necessary to feed the various electronics their intended voltages.

In the end, [tommycoolman] estimates it took about $200 and 30 hours of work to get the card cutter up and running again. The argument could be made that the value of his time needs to be factored into the repair bill as well, but even still, it sounds like a bargain to us; these machines have a four-figure price tag on them when new.

Stories like this one are important reminders of the all wondrous things you can find hiding in the trash. Any time a machine like this can be rescued from the junkyard, it’s an accomplishment worthy of praise in our book.