TechyMagThings

Supercapacitors rely mostly on double-layer capacitance to bridge the divide between chemical batteries and traditional capacitors, but they come with a number of weaknesses. Paramount among these are their relatively low voltage of around 2.7 V before their electrolyte begins to decompose, as well as their relatively high rates of self-discharge. Here a new design using lignin-derived porous carbon electrodes and a fluorinated diluent was demonstrated by [Shichao Zhang] et al., as published in Carbon Research, that seems to address these issues.

Most notable are the relatively high voltage of 4 V, an energy density of 77 Wh/kg and a self-discharge rate that’s much slower than that of conventional supercapacitors. In comparison with these supercapacitors, these demonstrated versions are also superior in terms of recharge cycles with 90% of capacity remaining after 10,000 cycles, which together with their much higher energy density should prove to be quite useful.

This feat is accomplished by using lignin as the base for the carbon electrodes to make a highly porous surface, along with the new electrolyte formulation consisting of alithium salt (LiBF₄) dissolved in sulfolane with TTE as a non-solvating diluent. The idea of using lignin-derived carbon for such a purpose has previously been pitched by [Jia Liu] et al. in 2022 and [Zhihao Ding] in 2025, with this seemingly one of the first major applications we may be seeing.

Although the path towards commercialization from a lab-assembled prototype is a rough one, we may be seeing some of these improvements come to supercapacitors near you sooner rather than later.

The Z80 has been gone a couple of years now, but it’s very much not forgotten. Still, the day when new-old-stock and salvaged DIP-40 packaged Z80s will be hard to come by is slowly approaching, and [eaw] is going to be ready with the picoZ80 project.

You can probably guess where this is going: an RP2350B on a DIP-40 sized PCB can easily sit on the bus and emulate a Z80. It can do so with only one core, without breaking a sweat. That left [eaw] a second core to play with, allowing the picoZ80 to act as a heck of an accelerator, memory expander, USB host, disk emulator– you name it. He even tossed in an ESP32 co-processor to act as a WiFi, Bluetooth, and SD-card controller to use as a virtual, wirelessly accessible disk drive.

The onboard ram that comes with an RP2350B would be generous by 1980s standards, but [eaw] bumped that up with an 8 MB SPRAM chip–accessed in 64 pages of 64 kB each, naturally. If more RAM than a very pricey hard drive wasn’t luxury enough, there’s also 16 MB of flash memory available. That’s configured to store ROM images that are transferred to the RAM at boot– the virtual Z80 isn’t grabbing from the flash at runtime in [eaw]’s architecture, because apparently there are limits to how much he wants to boost his retro machines.

There are already drivers to use in certain Z80 systems. You can of course configure it as a bare Z80 with no machine-specific emulation, or set up the picoZ80 with the “persona” of a classic Z80 machine. So far [eaw] has tried this on an RC2014 homebrew computer, as well as Sharp MZ-80A– which we’ve seen here before, in miniature–and Sharp MZ-700. The Sharp drivers are still works in progress, after which the Amstrad PCW8256/Tatung TC01 is apparently next. We’ve seen Amstrad PCWs here a time or two as well, come to think of it.

If somehow you missed it, the venerable Z80 only hit EOL in 2024, so supplies won’t be drying up any time soon. This hack is really more about the quality-of-life addons this allows. Come back in a decade, and we’ll see if the RP2350 lasts longer than the stack of NOS Z80s.

We don’t usually speculate on the true identity of the hackers behind these projects, but when [TN666]’s accoustic drone-detector crossed our desk with the name “Batear”, we couldn’t help but wonder– is that you, Bruce? On the other hand, with a BOM consisting entirely of one ESP32-S3 and an ICS-43434 I2S microphone, this isn’t exactly going to require the Wayne fortune to pull off. Indeed, [TN666] estimates a project cost of only 15 USD, which really democratizes drone detection.

The key is what you might call ‘retrovation’– innovation by looking backwards. Most drone detection schema are looking to the ways we search for larger aircraft, and use RADAR. Before RADAR there were acoustic detectors, like the famous Japanese “war tubas” that went viral many years ago. RADAR modules aren’t cheap, but MEMS microphones are– and drones, especially quad-copters, aren’t exactly quiet. [TN666] thus made the choice to use acoustic detection in order to democratize drone detection.

Of course that’s not much good if the ESP32 is phoning home to some Azure or AWS server to get the acoustic data processed by some giant machine learning model.  That would be the easy thing to do with an ESP32, but if you’re under drone attack or surveillance it’s not likely you want to rely on the cloud. There are always privacy concerns with using other people’s hardware, too. [TN666] again reached backwards to a more traditional algorithmic approach– specifically Goertzel filters to detect the acoustic frequencies used by drones. For analyzing specific frequency buckets, the Goertzel algorithm is as light as they come– which means everything can run local on the ESP32. They call that “edge computing” these days, but we just call it common sense.

The downside is that, since we’re just listening at specific frequencies, environmental noise can be an issue. Calibration for a given environment is suggested, as is a foam sock on the microphone to avoid false positives due to wind noise. It occurs to us the sort physical amplifier used in those ‘war tubas’ would both shelter the microphone from wind, as well as increase range and directionality.

[TN] does intend to explore machine learning models for this hardware as well; he seems to think that an ESP32-NN or small TensorFlow Lite model might outdo the Goertzel algorithm. He might be onto something, but we’re cheering for Goertzel on that one, simply on the basis that it’s a more elegant solution, one we’ve dived into before. It even works on the ATtiny85, which isn’t something you can say about even the lightest TensorFlow model.

Thanks to [TN] for the tip. Playboy billionaire or not, you can send your projects into the tips line to see them some bat-time on this bat-channel.

Graphics calculators are one of those strange technological cul-de-sacs. They rely on outdated technology and should not be nearly as expensive as they are, but market effects somehow keep prices well over $100 to this day. Given that fact, you might like to check out an open-source solution instead.

NumOS comes to us from [El-EnderJ]. It’s a scientific and graphic calculator system built to run on the ESP32-S3 with an ILI9341 screen. It’s intended to rival calculators like the Casio fx-991EX ClassWiz and the TI-84 Plus CE in terms of functionality. To that end, it has a full computer algebra system and a custom math engine to do all the heavy lifting a graphic calculator is expected to do, like symbolic differentiation and integration. It also has a Natural V.P.A.M-like display—if you’re unfamiliar with Casio’s terminology, it basically means things like fractions and integrals are rendered as you’d write them on paper rather than in uglier simplified symbology.

If you’ve ever wanted a graphics calculator that you could really tinker with down to the nuts and bolts, this is probably a great place to start. With that said, don’t expect your local school or university to let you take this thing into an exam hall. They’re pretty strict on that kind of thing these days.

We’ve seen some neat hacks on graphics calculators before, like this TI-83 running CircuitPython. If you’re doing your own magic with these mathematical machines, don’t hesitate to notify the tips line.

An MRI scan is never a pleasant occasion – even if you aren’t worried about the outcome, lying still in a confined, noisy space for long periods of time is at best an irksome experience. For hearing protection and to ameliorate boredom or claustrophobia, the patient wears headphones. Since magnets and wires can’t be used inside an MRI machine, the headphones have to literally pipe the sound in through tubes, which gives them poor sound quality and reduces the amount of noise they can block. [SomethingAboutScience], however, thinks that photoacoustic speakers could improve on these, and built some to demonstrate.

These speakers use the photoacoustic effect, which is mostly caused by surface heating when exposed to an intense light, then transferring the heat to the surrounding air, which expands. If the surface can transfer heat to the air quickly enough, and if the light source is modulated quickly, the rapid expansions and contractions in the surrounding air create sound waves. As a test, [SomethingAboutScience] shone a modulated 5-Watt laser on a piece of gold leaf, which produced recognizable music.

Gold leaf works because it absorbs blue light well and is thin enough to transfer heat to the air quickly. To cut out the absorbing surface, [SomethingAboutScience] also shone the laser directly into orange nitrogen dioxide gas, which produced a somewhat cleaner sound (in a purely auditory sense; nitrogen dioxide is quite dangerous, and calling it “a little toxic” is an understatement). Soot-coated glass also worked rather well, though a soot-coated glass smoking pipe didn’t provide the desired acoustics. He also 3D-printed an earphone shape with a gold leaf-lined cavity inside it, then used a fibre-optic cable to direct the laser light into it. We would be personally reluctant to couple a 5-Watt laser into a reflective cavity centimeters from our eardrums, but it didn’t appear to damage its surroundings.

We’ve seen the photoacoustic effect used before to perform long-range, almost silent command injection to voice assistants. It’s also possible to use lower-power lasers and beam sound directly into people’s ears.

Thanks to [Marble] for the tip!

The 3DFX Voodoo was not the first dedicated 3D graphics chipset by any means, but it became the favourite for gamers among the early mass-market GPUs. It would be found on a 3D-processing-only PCI card that sat on the feature connector of your SVGA card. The Voodoo took any game that supported its Glide API into the world of (for the time) smooth and beautiful 3D. They’re worth a bit now, but if you don’t fancy forking out for mid-’90s silicon in 2026, there’s another option. [Francisco Ayala Le Brun] has implemented the 3DFX Voodoo 1 in SpinalHDL for FPGAs.

The write-up goes into the Voodoo’s architecture. Where the parts of a modern GPU are programmable for the various functions it can do, in this part they are dedicated hardware functions for the various graphics tricks the chip can perform. Implementing such an architecture on an FPGA led to bugs and timing problems, and the write-up deals with that in detail.

The whole thing can be found in a GitHub repository if you’re curious, and is definitely worth a read for anyone interested in 1990s retrocomputing. 3DFX themselves would eventually be swallowed by Nvidia, a rival whose offerings would overtake them at the end of the ’90s, but they still represent a somewhat special moment. Don’t forget, if you have the real thing, you can probably upgrade its memory.

Header image: Konstantin Lanzet, GFDL.

On Friday, Reuters reported that Amazon is going to try to get into the smartphone game…again. The Fire Phone was perhaps Amazon’s biggest commercial misstep, and was only on the market for about a year before it was discontinued in the summer of 2015. But now industry sources are saying that a new phone code-named “Transformer” is in the works from the e-commerce giant.

At this point, there’s no word on how much the phone would cost or when it would hit the market. The only information Reuters was able to squeeze out of their contacts was that the device would feature AI heavily. Real shocker there — anyone with an Echo device in their kitchen could tell you that Amazon is desperate to get you talking to their gadgets, presumably so they can convince you to buy something. While a smartphone with even more AI features we didn’t ask for certainly won’t be on our Wish List, if history is any indicator, we might be able to pick these things up cheap on the second-hand market.

On the subject of AI screwing everything up, earlier this week, the Electronic Frontier Foundation reported that The New York Times had started blocking the Internet Archive’s crawlers, citing concerns over their content being scraped up by bots for training data. The EFF likens this to a newspaper asking libraries to stop storing copies of their old editions, and warns that in an era where most people get their news via the Internet, not having an archived copy of sites like The Times will put holes in the digital record. They also point out that mirroring web pages for the purposes of making them more easily searchable is a widely accepted practice (ask Google) and has been legally recognized as fair use in court.

Assuming we take the NYT’s side of the story at face value, there’s a tiny part of our cold robotic heart that feels some sympathy for them. Over the last year or so, we’ve noticed some suspicious activity that we believe to be bots siphoning up content from the blog and Hackaday.io, and it’s resulted in a few technical headaches for us. On the other hand, what’s Hackaday here for if not to share information? Surely the same could be said for any newspaper, be it the local rag or The New York Times. If a chatbot learning some new phrases from us is the cost of doing business in 2026, so be it. Can’t stop the signal.

Switching gears to the world of aerospace, NASA’s X-59 supersonic research aircraft had to abort a test flight on Friday after just nine minutes in the air. The plane is designed to demonstrate techniques which promise to reduce or eliminate the sonic booms heard on the ground during supersonic flight, and is currently being put through its paces at Armstrong Flight Research Center in Edwards, California.

The space agency hasn’t clarified exactly what the issue was, but after the pilot saw a warning indicator in the cockpit, the decision was made to end the flight early so engineers could take a look at the problem. Given that the X-59 went on to make an uneventful landing, it sounds like things weren’t too dire. Hopefully, that means it won’t be long before the sleek experimental aircraft is back in the air.

Friday also saw the towering Space Launch System rocket return to the launch pad ahead of a potential April 1st (no, really) liftoff for Artemis II. There are about a million things that could further delay the mission, from technical issues to suspicious looking cloud formations over Cape Canaveral, but we’re certainly in the final stretch now. The 10-day mission will see four astronauts run through a packed schedule of experiments and demonstrations as they become the first humans to swing by the Moon since the Apollo program ended in 1972.

Finally, the National Museum of the U.S. Air Force has released a video taken by a drone flying around their collection of Cold War era aircraft. Seasoned FPV pilots will probably notice it’s not the most technically impressive flight out there, but it does provide some viewpoints that simply wouldn’t be possible otherwise. It’s also a bit surreal to see these aircraft, once the absolute state-of-the-art and developed at an unimaginable cost, collecting dust while a $300 drone that packs in higher resolution optics and far more processing power literally flies circles around them.

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