Hackaday Podcast Episode 293: The Power Of POKE, Folding Butterflies, And The CRT Effect

October 18, 2024 by Kristina Panos 2 Comments

This week on the Podcast, Hackaday’s Elliot Williams and Kristina Panos joined forces to bring you the latest news, mystery sound, and of course, a big bunch of hacks from the previous week.

First up in the news: we’ve extended the 2024 Supercon Add-On contest by a week! That’s right, whether you were held up by Chinese fall holidays or not, here’s your chance to get in on this action.

We love to see the add-ons people make for the badge every year, so this time around we’re really embracing the standard. The best SAOs will get a production run and they’ll be in the swag bag at Hackaday Europe 2025.

What’s That Sound pretty much totally stumped Kristina once again, although she kind of earned a half shirt. Can you get it? Can you figure it out? Can you guess what’s making that sound? If you can, and your number comes up, you get a special Hackaday Podcast t-shirt.

Then it’s on to the hacks, beginning with what actually causes warping in 3D prints, and a really cool display we’d never heard of. Then we’ll discuss the power of POKE when it comes to live coding music on the Commodore64, and the allure of CRTs when it comes to vintage gaming. Finally, we talk Hackaday comments and take a look at a couple of keyboards.

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!

Download in DRM-free MP3 and savor at your leisure.

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Double-Slit Time Diffraction At Optical Frequencies

October 18, 2024 by Maya Posch 11 Comments

The double-slit experiment, first performed by [Thomas Young] in 1801 provided the first definitive proof of the dual wave-particle nature of photons. A similar experiment can be performed that shows diffraction at optical frequencies by changing the reflectivity of a film of indium-tin-oxide (ITO), as demonstrated in an April 2024 paper (preprint) by [Romain Tirole] et al. as published in Nature Physics. The reflectivity of a 40 nm thick film of ITO deposited on a glass surface is altered with 225 femtosecond pulses from a 230.2 THz (1300 nm) laser, creating temporal ‘slits’.

Interferogram of the time diffracted light as a function of slit separation (ps) and frequency (THz). (Credit: Tirole et al., Nature Physics, 2024)

The diffraction in this case occurs in the temporal domain, creating frequencies in the frequency spectrum when a separate laser applies a brief probing pulse. The effect of this can be seen most clearly in an interferogram (see excerpt at the right). Perhaps the most interesting finding during the experiment was how quickly and easily the ITO layer’s reflectivity could be altered. With ITO being a very commonly used composition material that provides properties such as electrical conductivity and optical transparency which are incredibly useful for windows, displays and touch panels.

Although practical applications for temporal diffraction in the optical or other domains aren’t immediately obvious, much like [Young]’s original experiment the implications are likely to be felt (much) later.

Featured image: the conventional and temporal double-slit experiments, with experimental setup (G). (Credit: Tirole et al., Nature Physics, 2024)

This Week In Security: Quantum RSA Break, Out Of Scope, And Spoofing Packets

October 18, 2024 by Jonathan Bennett 13 Comments

Depending on who you ask, the big news this week is that quantum computing researchers out of China have broken RSA. (Here’s the PDF of their paper.) And that’s true… sort of. There are multiple caveats, like the fact that this proof of concept is only factoring a 22-bit key. The minimum RSA size in use these days is 1024 bits. The other important note is that this wasn’t done on a general purpose quantum computer, but on a D-Wave quantum annealing machine.

First off, what is the difference between a general purpose and annealing quantum computer? Practically speaking, a quantum annealer can’t run Shor’s algorithm, the quantum algorithm that can factor large numbers into primes in a much shorter time than classical computers. While it’s pretty certain that this algorithm works from a mathematical perspective, it’s not at all clear that it will ever be possible to build effective quantum computers that can actually run it for the large numbers that are used in cryptography.

We’re going to vastly oversimplify the problem, and say that the challenge with general purpose quantum computing is that each q-bit is error prone, and the more q-bits a system has, the more errors it has. This error rate has proved to be a hard problem. The D-wave quantum annealing machine side-steps the issue by building a different sort of q-bits, that interact differently than in a general purpose quantum computer. The errors become much less of a problem, but you get a much less powerful primitive. And this is why annealing machines can’t run Shor’s algorithm.

The news this week is that researchers actually demonstrated a different technique on a D-wave machine that did actually factor an RSA key. From a research and engineering perspective, it is excellent work. But it doesn’t necessarily demonstrate the exponential speedup that would be required to break real-world RSA keys. To put it into perspective, you can literally crack a 22 bit RSA key by hand.

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MOTU Audio Interface Resurrected After Some Reverse Engineering

October 18, 2024 by Lewin Day 8 Comments

These days, when something electronic breaks, most folks just throw it away and get a new one. But as hackers, we prefer to find out what the actual problem is and fix it. [Bonsembiante] took that very tack when a MOTU brand audio interface wasn’t booting. As it turns out, a bit of investigative work led to a simple and viable fix.

The previous owner had tried to get the unit fixed multiple times without success. When it ended up on [Bonsembiante]’s bench, reverse engineering was the order of the day. Based around an embedded Linux system, there was lots to poke and prod at inside, it’s just that… the system wasn’t booting, wasn’t showing up over USB or Ethernet, or doing much of anything at all.

Extracting the firmware only revealed that the firmware was actually valid, so that was a dead end. However, after some work following the boot process along in Ghidra, with some external help, the problem was revealed. Something was causing the valid firmware to fail the bootloader’s checks—and with that fixed, the unit booted. You’ll have to read the article to get the full juicy story—it’s worth it!

We’ve seen [Bonsembiante’s] work here before, when they turned an old ADSL router into a functioning guitar pedal. Video after the break.

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Overcomplicating The Magnetic Compass For A Reason

October 18, 2024 by Dan Maloney 17 Comments

Some inventions are so simple that it’s hard to improve them. The magnetic compass is a great example — a magnetized needle, a bit of cork, and a bowl of water are all you need to start navigating the globe. So why in the world would you want to over-complicate things with something like this Earth inductor compass? Just because it’s cool, of course.

Now, the thing with complication is that it’s often instructive. The simplicity of the magnetic compass masks the theory behind its operation to some degree and completely fails to deliver any quantitative data on the Earth’s magnetic field. [tsbrownie]’s gadget is built from a pair of electric motors, one intact and one stripped of its permanent magnet stators. The two are mounted on a 3D printed frame and coupled by a long shaft made of brass, to magnetically isolate them as much as possible. The motor is powered by a DC supply while a digital ammeter is attached to the terminals on the stator.

When the motor spins, the stator at the other end of the shaft cuts the Earth’s magnetic lines of force and generates a current, which is displayed on the ammeter. How much current is generated depends on how the assembly is oriented. In the video below, [tsbrownie] shows that the current nulls out when oriented along the east-west axis, and reaches a maximum along north-south. It’s not much current — about 35 microamps — but it’s enough to get a solid reading.

Is this a practical substitute for a magnetic compass? Perhaps not for most use cases, but a wind-powered version of this guided [Charles Lindbergh]’s Spirit of St. Louis across the Atlantic in 1927 with an error of only about 10 miles over the trip, so there’s that. Other aircraft compasses take different approaches to the problem of nulling out the magnetic field of the plane.

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Building A ZX Spectrum Using Only New Parts

October 17, 2024 by Lewin Day 29 Comments

Ah, the Sinclair ZX Spectrum. A popular computer in Britain and beyond, but now rather thin on the ground. If you can’t find one, fear not, for now—you can apparently build a new one with new parts! [TME Retro] is here to demonstrate how.

Before you get excited, no—Sinclair has not risen from the dead. Instead, it’s simply down to the state of the retrocomputing community. There are enough reproduction parts and components out there for the ZX Spectrum that it’s now possible to assemble the whole computer from new bits. You can get new cases and new mechanical keyboards, and a 100% compatible motherboard in the form of the Harlequin board. The latter even reproduces the unobtainable Spectrum ULA glue logic chip in raw logic!

It’s neat to see the ZX Spectrum live on decades after the production lines ground to a halt. We’ve seen similar feats achieved with the legendary Commodore 64; you’d think we had enough of them given they were the best-selling computer of all time. Video after the break.

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Redbox Is Dead, But The Machines Are Kind Of Hanging On

October 17, 2024 by Lewin Day 37 Comments

Redbox was a service for renting DVDs from automated kiosks. The business was going well until it wasn’t anymore, and then the company went bankrupt in July this year. And yet… the machines live on. At least, that’s according to YouTuber [Smokin’ Silicon], who spotted some remaining Redbox kiosks out and about. Including at his local Walmart!

Here’s the thing. There’s not one big switch at Redbox that turns all the machines off, and even if there was—nobody hit it the moment the company declared bankruptcy. Thus, when [Smokin’ Silicon] rocked up to Walmart, he was able to flick through the movies and even add one to cart for purchase. However, trying to complete the transaction failed—the kiosk eventually reported itself as out of service. That makes sense—you’d expect payment processing to be the first thing to go down.

However, other Redbox kiosks were different. A kiosk at a Food Lion location actually still worked—and [Smokin’ Silicon] was able to complete the transaction and walk away with a Black Adam disc! On a second trip, he was able to walk away with even more!

The rest of the video dives into Redbox lore and other posts online about the status of the company, software, and hardware. Apparently, someone on Reddit was claiming they had the Redbox kiosk OS available. Meanwhile, some users have had trouble returning their discs because the company is now defunct. However, [Smokin’ Silicon] was able to return his without issue. Ultimately, though, he recommends his viewers to go out and score as many DVDs and Blu Rays as possible from the machines since soon enough, they’ll be gone forever.

The fact is, businesses are big and Kafkaesque, the kiosks are scattered all over the country, and so it’s anybody’s guess if and when they stop working. Back when this website began, a redbox was something different entirely. Video after the break.

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