Author: Jenny List

3277 Articles

Break The Air Gap With Ultrasound

June 29, 2025 by 15 Comments

In the world of information security, much thought goes into ensuring that no information can leave computer networks without expressly being permitted to do so. Conversely, a lot of effort is expended on the part of would-be attackers to break through whatever layers are present. [Halcy] has a way to share data between computers, whether they are networked or not, and it uses ultrasound.

To be fair, this is more of a fun toy than an elite exploit, because it involves a web interface that encodes text as ultrasonic frequency shift keying. Your computer speakers and microphone can handle it, but it’s way above the human hearing range. Testing it here, we were able to send text mostly without errors over a short distance, but at least on this laptop, we wouldn’t call it reliable.

We doubt that many sensitive servers have a sound card and speakers installed where you can overhear them, but by contrast, there are doubtless many laptops containing valuable information, so we could imagine it as a possible attack vector. The code is on the linked page, should you be interested, and if you want more ultrasonic goodness, this definitely isn’t the first time we have touched upon it. While a sound card might be exotic on a server, a hard drive LED isn’t.

Reading The Chip In Your Passport

June 28, 2025 by 37 Comments

For over a decade, most passports have contained an NFC chip that holds a set of electronically readable data about the document and its holder. This has resulted in a much quicker passage through some borders as automatic barriers can replace human officials, but at the same time, it adds an opaque layer to the process. Just what data is on your passport, and can you read it for yourself? [Terence Eden] wanted to find out.

The write-up explains what’s on the passport and how to access it. Surprisingly, it’s a straightforward process, unlike, for example, the NFC on a bank card. Security against drive-by scanning is provided by the key being printed on the passport, requiring the passport to be physically opened.

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Hackaday Podcast Episode 326: A DIY Pockels Cell, Funny Materials To 3D Print With, And Pwning A Nissan Leaf

June 27, 2025 by 3 Comments

Time for another European flavoured Hackaday Podcast this week, as Elliot Williams is joined by Jenny List, two writers sweltering in the humidity of a Central European summer. Both of our fans and air conditioners made enough noise to be picked up on the microphone when they were turned on, so we’re suffering for your entertainment.

The big Hackaday news stories of the week are twofold, firstly a cat-themed set of winners for the 2025 Pet Hacks contest, and then the announcement of a fresh competition: the 2025 Hackaday One Hertz Challenge. Get your once-a-second projects ready!

This week gave us a nice pile of interesting hacks, including some next-level work growing and machining the crystal for a home-made Pockels cell light valve, an upcoming technique for glass 3D prints, and enough vulnerabilities to make any Nissan Leaf owner nervous. We note that mechanical 7-segment displays are an arena showing excellent hacks, and we’re here for it.

Meanwhile among the quick hacks a filament made of PLA with a PETG core caught Elliot’s eye, while Jenny was impressed with a beautifully-made paper tape punch. Finally in the can’t miss section, The latest in Dan Maloney’s Mining and Refining series looks at drilling and blasting. Such an explosive piece should come last, but wait! There’s more! Al Williams gives us a potted history of satellite phones, and explains why you don’t carry an Iridium in your pocket.

Or download it your own fine self. MP3 for free!

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A Cheap Smart Plug To Block Distractions

June 27, 2025 by 19 Comments

We have all suffered from this; the boss wants you to compile a report on the number of paper clips and you’re crawling up the wall with boredom, so naturally your mind strays to other things. You check social media, or maybe the news, and before you know it a while has been wasted. [Neil Chen] came up with a solution, to configure a cheap smart plug with a script to block his diversions of choice.

The idea is simple enough, the plug is in an outlet that requires getting up and walking a distance to access, so to flip that switch you’ve really got to want to do it. Behind it lives a Python script that can be found in a Git Hub repository, and that’s it! We like it for its simplicity and ingenuity, though we’d implore any of you to avoid using it to block Hackaday. Some sites are simply too important to avoid!

Of course, if distraction at work is your problem, perhaps you should simply run something without it.

Revealing The Last Mac Easter Egg

June 26, 2025 by 34 Comments

A favourite thing for the developers behind a complex software project is to embed an Easter egg: something unexpected that can be revealed only by those in the know. Apple certainly had their share of them in their early days, a practice brought to a close by Steve Jobs on his return to the company. One of the last Macs to contain one was the late 1990s beige G3, and while its existence has been know for years, until now nobody has decoded the means to display it on the Mac. Now [Doug Brown] has taken on the challenge.

The Easter egg is a JPEG file embedded in the ROM with portraits of the team, and it can’t be summoned with the keypress combinations used on earlier Macs. We’re taken on a whirlwind tour of ROM disassembly as he finds an unexpected string in the SCSI driver code. Eventually it’s found that formatting the RAM disk with the string as a volume name causes the JPEG to be saved into the disk, and any Mac user can come face to face with the dev team. It’s a joy reserved now for only a few collectors of vintage hardware, but still over a quarter century later, it’s fascinating to learn about. Meanwhile, this isn’t the first Mac easter egg to find its way here.

There’s A New Reusable Rocket, And It’s A Honda

June 24, 2025 by 18 Comments

As we watched the latest SpaceX Starship rocket test end in a spectacular explosion, we might have missed the news from Japan of a different rocket passing a successful test. We all know Honda as a car company but it seems they are in the rocket business too, and they successfully tested a reusable rocket. It’s an experimental 900 kg model that flew to a height of 300 m before returning itself to the pad, but it serves as a valuable test platform for Honda’s take on the technology.

It’s a research project as it stands, but it’s being developed with an eye towards future low-cost satellite launches rather than as a crew launch platform.As a news story though it’s of interest beyond its technology, because it’s too easy to miss news from the other side of the world when all eyes are looking at Texas. It’s the latest in a long line of interesting research projects from the company, and we hope that this time they resist the temptation to kill their creation rather than bring it to market.

3D Print Glass, Using Accessible Techniques

June 22, 2025 by 21 Comments

When seeing a story from MIT’s Lincoln Labs that promises 3D printing glass, our first reaction was that it might use some rare or novel chemicals, and certainly a super-high-tech printer. Perhaps it was some form of high-temperature laser sintering, unlikely to be within the reach of mere mortals. How wrong we were, because these boffins have developed a way to 3D print a glass-like material using easy-to-source materials and commonly available equipment.

The print medium is sodium silicate solution, commonly known as waterglass, mixed with silica and other inorganic nanoparticles. It’s referred to as an ink, and it appears to be printed using a technique very similar to the FDM printers we all know. The real magic comes in the curing process, though, because instead of being fired in a special furnace, these models are heated to 200 Celsius in an oil bath. They can then be solvent cleaned and are ready for use. The result may not be the fine crystal glass you may be expecting, but we can certainly see plenty of uses for it should it be turned into a commercial product. Certainly more convenient than sintering with a laser cutter.