TechyMagThings

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.

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.

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.

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.

There is a phenomenon where as you get older, your sense of scale becomes somewhat fixed in the earlier era that shaped you– things like expecting the Dollar Store to carry items for 1$, or to get a burger and fries for less than twenty bucks– or, in this case, thinking of supercomputers as being petaflop-scale machines. That’s not wrong, per se– most of the world’s fastest machines benchmarks are best measured in petaflops– but when you’re clocking at 2198 of the things, it becomes easier just to say that the LineShine computer can do 2.188 exaflops. At double precision. With CPUs only. Yes, we are impressed.

Even more impressive is that this machine just debuted in China, which means it was built without the benefit of the latest-and-greatest Western chips, thanks to US sanctions. It’s using a made-in-China LX2 CPU with 304 ARMv9 cores onboard. Well, it’s actually using around 46 thousand of them, but who’s counting?

Each CPU actually consists of two separate compute dies and onboard high bandwith memory (HBM) and DRAM– 4GB of HBM and 32GB of DDR5. The 152 ARMv9 CPU cores on each chip are all built with Scalable Vector Extensions (SVE) and Scalable Matrix Extensions (SME), so despite the lack of GPUs LineShine will have no problem doing the sorts of vector processing that is traditional for high-performance computing, given the 13.79 million cores.

On the other hand, the lack of GPUs shows when you change benchmarks– LineShine is number one in the rankings for High Performance Linpack (HPL), but getting outside the 64-bit box, the supercomputer only hits number four on the HPL-MxP mixed-precision benchmark, behind machines that pair their CPUs with accelerators like GPUs or NPUs. That may mollify the American ego, as while their El Capitain was bumped to second place on the HPL list, they can still claim the pole position on HPL-MxP. Which computer is actually more capable depends entirely on what you want to do with it, and neither Lawrence Livermore National Laboratory nor China’s National Supercomputing Centre in Shenzhen advertise their compute queues, though this paper suggests at least one job will be crunching earth observation data.

The definition of a supercomputer has shifted over time, and it’s only a matter of time before LineShine and El Capitain end up on the auction block, like other supercomputers before them. We might question it when it comes to desktops, but for institutional HPC, no amount of computing ever seems to be enough.

[Stefan] of CNC Kitchen has an informative video describing his experiences with trying to cleanly laser-mark 3D printed plastics using different methods, and it also happens to be a fantastic tour of all the different laser options available to hobbyists and workshops these days.

Laser marking is a fast and effective way to put things like product names, serial numbers, and other information on plastics. [Stefan] wondered whether laser options would be capable of creating clean and professional marks on 3D-printed items, and approached things with his usual attention to detail.

How does a laser mark plastic? When the laser hits the material, its energy is dumped into it and can cause pigment bleaching, microfoaming, charring, melting, or ablation (vaporizing) of the surface. The goal is to have a combination of laser and material that delivers a crisp, high-contrast result.

There are several kinds of laser technologies easily available today, and of course a variety of filament types. [Stefan] printed a whole bunch of different PLA, PETG, ASA, TPU, and polycarbonate samples in different colors and tested them with different laser machines, including:

• UV laser (355 nm wavelength)
• Blue diode laser (450 nm wavelength)
• MOPA fiber laser (1,064 nm wavelength)
• CO₂ laser (10,600 nm wavelength)

So is it possible? Yes, but it’s still a bit of a fussy process. There isn’t a one-size-fits-all solution for marking plastic, because results depend a lot on the the right combination of laser type, settings, and target material. That being said, [Stefan] was able to obtain some really great results.

Overall the UV laser was the most suited to marking 3D-printed plastics. [Stefan] says it produced the cleanest results on the widest range of materials with the least fiddling. The MOPA fiber laser also worked, but is clearly more of a metal-marking tool. We’ve seen them etch super-fine PCB traces and while great results are possible it isn’t quite in its element with plastics. Other lasers could get good results under just the right circumstances, but are overall best suited to cutting tasks rather than marking thermoplastics.

Check out the video below for the full details, including some really fantastic closeups.

How do you measure the inside of a cave? You could do a bunch of hard work with classic surveying gear… or you could just use a laser scanner. [9nl] did the latter, with a scanning rig of his own creation.

The build is based around an Ouster VLP-16 mid-range lidar sensor. It shoots out pulses of light and measures how long it takes them to bounce back in order to determine the range of objects in the vicinity, and thus can be used to great effect for 3D scanning tasks. For [9nl], though, the sensor had a serious limitation. Since it only had a 40-degree field of view, it wasn’t ideal for the desired application of scanning a cave. However, by building a custom rig that could rotate the sensor, [9nl] ended up with a rig that could 3D scan an area through a full 360 degrees. There’s nothing wildly complex involved, just some good old mechanical engineering—putting the sensor on a shaft and spinning it with a belt drive. Then it’s just a matter of processing the data correctly. The hard part is then getting the rig in and out of the cave without breaking anything.

There are plenty of off-the-shelf 3D scanning solutions that can do this work, but few of them come cheap. Plus, rolling your own teaches you a great many things as you hone your solution to your particular needs. Video after the break.

[Thanks to Kovy Jacob for the tip!]