Alan Turing’s Remarkable, Nearly-Forgotten Voice Encryption Device

June 26, 2026 by No comments

[Popular Mechanics] has an interesting article about Alan Turing’s nearly-forgotten speech encryption device. Codenamed Delilah, it was in many ways an early form of digital encryption. It was secretly developed alongside his most famous wartime achievement of breaking the encryption used by the Nazis’ Enigma machine; itself a remarkable device we’ve covered in detail in the past.

Delilah was developed at a separate location, and Turing worked with a young electrical engineer by the name of Donald Bayley who not only helped Turing implement design concepts and theory as practical circuitry, but took copious notes of their work and discussions. His documents, which went up for auction a few years after his death in 2023, reveal a first-hand account of their work.

SIGSALY (the name is not an acronym, by the way) was a working voice encryption system whose main drawbacks were its massive size, weight, and power requirements. [image: Wikipedia]
Back then, a vocal encryption system did exist. Bell Labs had developed SIGSALY, a seriously top-secret system that provided encrypted voice communications at the highest levels. But one of SIGSALY’s biggest drawbacks was that it was absolutely monstrous.

Delilah did the same job, but was portable and battery-powered. Delilah was three small boxes weighing around 39 kg, and it’s hard to overstate just how remarkable of a feat of miniaturization this was. However, by the time Delilah was wrapped up, the war was over and the project wound down without ever being produced or deployed in any meaningful way.

Encrypted communications is standard stuff today, but back then there was simply no need for a vocal encryption system in peacetime. The reason we know what we do today is thanks mainly to the effort Bayley put into documenting things.

It again demonstrates that if the people involved don’t write things down while they know it, that knowledge can simply disappear. Sometimes people make the effort and the rest of us benefit, like with the Delilah project and also with the history of liquid rocket propellants — a dry-sounding topic that we assure you is anything but.

This Kid-Friendly Laptop Build Is The Antidote To Age Verification

June 26, 2026 by 21 Comments

Age-verification has been a topic of hot debate recently, with many in the community feeling that keeping kids safe online is better handled by the parents. But what does that look like these days? [EposVox] has been working on a child-safe laptop to try and solve the problem, but depending on how you look at it, it also shows why non-technical people may feel they need the government involved.

His setup may seem simple to many readers — a carefully curated selection of edutainment apps running under Kubuntu on an old laptop. We particularly like his choice not to give access to the applications menu, but give himself a hotkey for the terminal if he needs to access something outside of the curated selection of software. Most things are local, though some browser games and cloud tools are made available via Vivaldi’s app mode. In this case there is no actual browser access for junior just yet, as the child in question is seven years old.

All in all, it sounds like less than an hour to set up. Assuming you’ve got experience with desktop Linux, anyway. Consider, though that it took [EposVox] an entire day just to get Kubuntu installed, and you begin to see why the average person might look kindly on a politician offering to solve these problems for them. For those that need it, [EposVox] points out some Windows-based alternatives for childproofing your PC, including the absolute minimum of DNS filtering. But the same problem applies: how many people outside our bubble know how to set that up?

While there’s an argument to be made that the sort of age-verification laws being passed are examples of government overreach, these laws aren’t facing a lot of push-back because most people aren’t technically literate enough to realize the problems with them. They like the idea of their kids being protected, and they don’t know how to set up an old PC the way [EposVox] does here.

It’s a real shame, especially considering that none of this is new. We featured a kid-friendly, Windows-based computer setup years ago. But it is what it is. Hopefully these sorts of hacks don’t end with the roll-out of age verification, because it’s a much better way to do it.

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Make That Smart TV Into A Computer

June 25, 2026 by 11 Comments

The smart TV is a fixture in most houses, variously an entertainment portal, corporate data gathering tool, or sometimes an outright spy. It’s a nice monitor with a computer built in, so can that computer be released to do something else? It’s a question [Xen’on] is answering, on an Android-based TV.

The guide is not too different from many others relating to Android phones, with a few quirks. An Android Debug Bridge (ADB) connection is established, root access is gained using Shizuku, and then it’s a case of installing a more conventional Linux front end with the Openbox window manager through Termux. There are some TV-specific things to do with handling power cycles, but the TV is now a usable Linux box.

It’s always good to see someone retrieve the Linux underneath a locked-down device, but the system spec tells the real story. By the looks of things this TV is a few years old as it had an Android version that’s a bit long in the tooth, and thus it also packs an aged version 4.x kernel. Couple that with a more seat-of-your-pants experience compared to a regular distro where many of the annoyances are taken care of, this isn’t an easy route to a trouble free desktop. Instead it has a lot of potential for making the TV what it was intend to be, an entertainment device. Merely one that gives much more software freedom.

Meanwhile, this isn’t the first Termux guide we’ve seen.

Increasing Photon Upconversion Efficiency With Structural Exciton Localization

June 25, 2026 by 5 Comments

In structures like photovoltaic cells there is only a limited spectrum of wavelengths that can perform useful work, with the remaining wavelengths of electromagnetic radiation effectively wasted. If the energy of such wavelengths could be coaxed into this useful spectrum, this could then correspondingly boost the performance of the devices, but doing so is not straightforward. Going from lower-energy photons to higher-energy photons is very inefficient, with a recent study by [Thilini Ishwara] et al. demonstrating a liquid triplet medium that has a conversion efficiency of about 8.2%.

Generally the absorption and emission of electromagnetic radiation involves a shift to a lower energy state, the Stokes shift, but the inverse anti-Stokes shift – the goal of photon upconversion – is decidedly less common, even if it finds uses today in for example industrial pigments that can absorb in the near-infrared and re-emit in the visible spectrum. This is practical in luminescent displays and anti-counterfeiting measures, where details like conversion efficiency aren’t paramount.

Unlike the Stokes shift, the mechanisms that underlie the anti-Stokes shift either require cooperation from the material’s lattice, or – in the case of organic molecules – what is termed triplet-triplet annihilation (TTA), also known as photochemical upconversion (PUC). This involves an absorbing species, a sensitizer and an emitting species, allowing for the summing of multiple lower-energy photons into a higher-energy photon, with this 2023 review article by [Jiale Feng] et al. providing a good primer.

In the study by [Ishwara] et al. this triplet medium is 9,10-bis(n-octyl-diisopropylsilylethynyl)anthracene (NODIPS-An), affixed to a nanostructured alumina scaffold (see top image). After characterizing the assembled device and taking internal losses due to e.g. reabsorption into account, the final conversion efficiency of 8.2% was established.

Of course, TTA isn’t the only way to do PUC, with SOMET (singlet oxygen mediated energy transfer) being an alternative approach, with [Roslyn Forecast] et al. comparing the two in a 2023 article. As noted in its conclusion SOMET is currently most suited to PUC to the red and infrared regions of the spectrum. For now research continues with no clear path to commercialization visible yet.

Fixing A Warped Paperback Spine With Gentle Heating

June 25, 2026 by 3 Comments

Although paperbacks are a much-loved aspect of the literary world, they are not really intended to last the decades the way that hardcover books are. Beyond the typical ravaged covers, paperbacks also tend to suffer from a warped spine, where the formally flat spine gets a definite inwards curve due to the ravages of moisture, temperature, failing glue and the passing of time in general. If this bothers you, then [Book Care Studio] shows a simple technique using which these spines can be flattened again.

All that you need for this approach are two cutting boards and two clamps to provide some clamping force on the book, along with a heat gun and some patience.

The book is clamped between the two boards with the spine sticking out. By putting said spine flat on e.g. a table and pushing on the opposite side while alternatingly briefly releasing the clamps, the spine can be forced into a flatter state. Without forcing this and then flipping the paperback sandwich around to heat the spine with the heat gun, the glue of the binding in the spine can then be softened sufficiently that a few of these push-heat cycles should be enough to straighten the spine.

Other than rebinding the book as for example public libraries are wont to do with a hardcover conversion of flimsy paperbacks, this simple approach should clean up a ratty-looking paperback collection. While one can definitely argue that half the charm of old paperbacks are the wrinkles, curves and intense smell of acidifying paper, it’s always good to have options like this at one’s disposal.

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Cheap 80s Keyboard Gets Modern Brain Upgrade

June 25, 2026 by 13 Comments

The 1981 Casio VL-1 was a fine cheap keyboard. It had a robust build, though an admittedly limited sound palette. [Max Vega] had one of these charming instruments, and decided to use modern tech to rebrain it for the modern world.

The original electronics of the VL-1 were largely surplus to requirements for this build. The original interface and speaker were kept in service, while the rest of the monophonic sound synthesis hardware was removed. [Max Vega] enlisted an ESP32-C3 to run the show, turning the VL-1 into a ROMpler instead. If you’re unfamiliar with the term, it refers to a keyboard or other instrument that relies on hardcoded sample playback instead of raw synthesis. The ESP32 loads its samples from a microSD card, which provides an enormous amount of storage for different sound packs. Selecting different instruments is handled with a simple interface built around the original buttons and a OLED screen.  Playing the instrument is still the same using the simple keyboard, though [Max] also implemented some extra fun modes that play chords at a single touch.

If you want a fun, versatile keyboard instrument that fits perfectly in a backpack, it’s hard to go wrong with a build like this. We’ve seen similar Casio keyboard hacks before, too. Video after the break.

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CSS On The ESP32

June 25, 2026 by 12 Comments

There are lots of graphics libraries available for the ESP32, and lots of ways to program one to boot. Even still, most of us wouldn’t immediately think to CSS when it comes to embedded products — yet that’s now a thing on the Espressif platform, apparently.

The Gea stack allows one to compose CSS and TypeScript code that is then turned into generated C++ code that compiles to native firmware. The team behind Gea have demoed this ability by running a 3D cube animation on an ESP32 at up to 60 FPS. This isn’t some ugly, low-res wireframe demo, either. It’s a full-color animation running on a 410×502 AMOLED screen. It’s very fluid, and can even handle transparency on the cube faces (albeit with a performance penalty).

It’s worth noting that this isn’t a full browser engine. As you might expect, some concessions had to be made to get it running on the ESP32. Namely, it doesn’t handle “:hover” states because it’s designed for touchscreen use, fonts are rasterized, and the UI tree is limited to just 512 nodes. Regardless, it shows that using CSS and TypeScript to develop for the ESP32 is entirely possible without some crazy loss of performance. If you want to build easy interfaces on an ESP32 while leaning on web dev experience, this could be very useful indeed.

There are lots of fun ways to write code for the ESP32; you can even try MicroPython if you like.

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