Leaded fuel is considered one of the greatest environmental failures in modern human history. Adding tetraethyl lead to gasoline reduced knock in internal combustion engines, which was widely considered a good thing. It was only later that the deleterious health effects came into view, by which point there was a massive fleet of lead-dependent automobiles and an industry reluctant to change. Still, the tide turned, and over the last 50 years, unleaded fuel has become the norm for automotive use across the world.

And yet, there remains a hold out—a world where engines still burn leaded fuels and spray their noxious fumes across the countryside. In the aviation sector, leaded fuel remains a normal part of everyday operations to this day amidst concerted efforts to eliminate it for good.

“Low” Lead

Piston-engined aircraft do not typically run on the same fuels as automobiles. Instead, they burn aviation gasoline, or Avgas, which comes in specific grades and is designed to suit the needs of aircraft engines, by being less volatile and more suitable for high-performance applications.

The most common grade is 100LL (low lead), which is used widely across North America and Western Europe. Despite the moniker, the fuel contains 0.56 grams/litre of tetraethyl lead (TEL), somewhat higher than many leaded automotive fuels used in the 20th century. As with ground-based applications, the additive is used to provide a measure of valvetrain protection by offering cooling and preventing microwelds between contacting parts. It also provides an easy increase to the fuel’s effective octane rating. The latter is particularly useful in aviation contexts where engines run under high load conditions for extended periods of time, and where performance is critical.

Other grades of aviation fuel are also in regular use in various parts of the world, many of which still contain significant levels of TEL as well. It’s worth noting that turbine-based aviation engines are not relevant to this issue, as they burn kerosene-based fuels which are lead-free.

The basic makeup of aviation gasoline was largely decided by the mid-1940s, a period in which fuels were heavily developed to suit the needs of then-cutting-edge piston military aircraft. At the time, knock resistance was key to enabling supercharged aircraft engines to achieve higher power levels, a point of key military interest during World War II. Tetraethyl lead was an easy way to achieve this, and this requirement also led to development of technologies like water-methanol injection.

Unfortunately, burning leaded fuel effectively sprayed significant amounts of lead into the environment. This lead to elevated blood lead levels in the population, causing premature deaths, neurological damage, and negatively impacting development in children. This is perhaps somewhat galling given that the inventor of TEL, Thomas Midgley Jr., himself suffered significant health effects from the compound. Many workers would also die during early efforts to produce industrial amounts of TEL in the 1920s. It’s one of many examples from the 20th century of industrial will prevailing in spite of obvious severe health risks from a dangerous but otherwise useful chemical.

Despite early knowledge of the dangers, it took some time for the negative impacts of TEL to become readily apparent on a wide scale. Japan lead the charge with a leaded fuel ban for automotive use in 1986, with other developed countries following suit in years to come. It would take decades for the last domino to fall, with Algeria finally outlawing the fuel in 2021.

However, the aviation world has not been so quick to abandon lead. Much of the reasoning behind this comes down to practicality. Aviation piston engines simply require high octane fuel and TEL has proven one of the easiest ways to achieve a high rating. 100LL, for example, has a MON rating of 100, which is quite high compared to even premium gasoline used in automotive applications.

Engines designed to run on TEL often rely on the additive to prevent excessive valve wear, too, so running these engines on non-leaded fuels can significantly increase wear. This would be an expensive inconvenience in an automotive application, but when the engine is what’s keeping you in the sky, it’s less desirable to risk a failure by running a cleaner fuel.

In 2019, the FAA estimated that there were 167,000 aircraft in the United States that relied on 100LL avgas, and 230,000 worldwide. The agency had asked in 2014 for industry proposals to make a transition towards unleaded fuels for internal combustion applications.

However, testing revealed issues with proposed alternatives, and was eventually halted in 2018. The FAA has since provided a draft plan in 2026 that lays out the timeline to phase out leaded aviation fuel for good. The intent is to end the use of 100LL fuel in the United States by 2030, excepting Alaska, which will phase out the fuel in 2032. The intention is to take an incremental approach, giving the industry time to develop and certify unleaded replacement fuels—with G100UL, 100R, and UL100E all candidates for FAA approval.

Real-world use of these fuels will then be monitored for compatibility and safety and to determine if further support or changes are required to manage the transition away from 100LL. For now, the timelines are still subject to change, particularly in Alaska, where piston-engined aircraft are particularly vital for transport and logistics are harder to manage. However, it marks a very real commitment to ending the use of leaded aviation for good, at least in the United States. If the FAA does manage to pull off this feat, it should be readily achievable for other countries around the world.

Ultimately, leaded aviation fuels aren’t causing the same level of damage to humanity and the environment as leaded automotive fuels, purely by virtue of their more limited use. Still, it’s never ideal to be spraying lead into the environment, and the health risks are always going to be elevated for those near general aviation airports or under flightpaths of piston-engined aircraft. It’s positive that there is a real commitment to end the use of these fuels, but much work remains to be done to end the reign of tetraethyl lead for good.

Featured Image: “Tetraethyl Lead” by [David Brodbeck]

Was there ever anything wrong with simple paper price labels? Absolutely not. And yet, the world invented the electronic price tag anyway. If you happen to come across some of these devices and want to hack them, you might like TagTinker from [i12bp8].

TagTinker is a Flipper Zero application specifically built for talking to infrared electronic shelf labels (ESLs). These are e-paper devices that receive commands and updates via an infrared interface, and they’re relatively simple to talk to. [i12bp8] built upon previous work from [furrtek] which revealed the protocols used to update these devices, and implemented it into an app that runs on the Flipper. It can do neat things like scan the NFC tags built into ESLs to ID them, deploy bitmap images to the tags, or run live-updated dashboards on the devices with the aid of a Flipper WiFi devboard.

If you’ve always wanted to play with these tags but didn’t want to do the grunt work yourself, it just got a whole lot easier to mess around. Though, it’s worth noting, [i12bp8] has strictly prohibited any illegal uses of this app, so be good out there. We’ve seen these tags repurposed before, too – who knew they could make such good conference badges? 

A time domain reflectometer (TDR) is a useful tool to have for finding faults in a wiring harness. However, they don’t come cheap, putting them out of reach for many shadetree mechanics that like to work on their own cars. However, [László SZŐKE] has been exploring a neat way to build a similar device on the cheap.

Typically, time domain reflectometry involves shooting a short electric pulse down a wire, and listening for how long it takes to bounce back. The time depends on the length of the wire, so it can be used to determine the location of a break in conductivity. Unfortunately, these pulses move so fast that very fast, very expensive hardware is needed to make these measurements.

[László’s] technique relies on lower-tech hardware. Instead of sending a very short pulse down a wire, his rig uses a cheap C-Media USB audio device to send a 4 kHz or 8 kHz sine wave instead. Then, by listening to the reflection and measuring the phase shift, it’s possible to detect the distance to the end of the wire (or a break along its length). Some supporting hardware is required for protection’s sake, and to tune the setup for measuring shorter or longer cabling. However, with some smart software processing, [László] states that it’s possible to measure down to 1 cm resolution.

The idea is that this setup could prove particularly useful for automotive troubleshooting. If you measure a wire and the device reports a length of 30 cm, when you know the wire stretches several meters into the engine bay… you know there’s a break around 30 cm from your measurement point.

There’s still plenty of work to be done – for now, [László] is working on a new prototype that should have better performance when testing shorter cables. Still, we love to see this sort of out-of-the-box thinking put towards a common troubleshooting task. If you’re doing fun signal analysis work of your own, don’t hesitate to light up the tipsline.

Although modern cameras can, with skill and good conditions, produce photographs nearly indistinguishable from the original scene, this fidelity relies on the limitations of human vision. According to the trichromatic theory, humans perceive light as a mixture of three colors, which can be recorded and represented by cameras, displays, and color printing; a spectrometer, however, can detect a clear distance between the three colors present in a photograph and the wide range of spectra in the original scene. By contrast, one of the earliest color photography methods, Lippmann plates, captured not just true color, but true spectra.

A Lippmann plate, as [Jon Hilty] details, starts with a layer of photographic gel containing extremely fine silver halide crystals over the back of a glass plate. This layer is placed on top of a mirror, traditionally a mercury bath, and put in the camera. When light passes through the emulsion and reflects off the mirror, it interferes with incoming light to create a standing wave. The portions of the emulsion at the wave’s antinodes absorb the most energy, converting local silver halide crystals into reflective silver. The spacing of the silver particles depends on the incoming light’s wavelength, and is fixed in place during the development process.

This creates a matrix of vertically-stacked diffraction gratings, each diffracting back the original wavelength when illuminated with white light. Unlike normal diffraction gratings, the wavelength of diffracted light doesn’t depend strongly on the viewing angle; since the interference structure here is vertically-arranged, it refracts a narrow range of wavelengths across all possible viewing angles. The viewing angles, however, are limited; unlike with dye-based photographs, you can only view the colors nearly straight-on. This, along with the necessity for long exposures, the chance of producing washed-out colors, and the impossibility of creating reprints, kept Lippmann plates from ever really catching on. The basic concept lives on in holograms, which encode spatial information in a similar kind of photographically-formed diffraction pattern.

For a more conventional method of color photography, we’ve also seen a recreation of the autochrome method. Alternatively, check out this homemade silver halide photography emulsion.

Thanks to [Stephen Walters] for the tip!

Although the ReactOS project is in no rush to dethrone Windows as the desktop operating system of choice, this doesn’t mean that some real changes aren’t happening. Most recently two big changes got merged, the first pertaining to the separate boot- and live CD images that are now merged into a single image, and the second being a new PnP-aware ATA storage stack for ATA and AHCI devices, with NT6+ compatibility.

Although there is still a separate live CD for now, this first change means that testing and installing ReactOS becomes easier, and that the old-school text-based installer may soon be on its way out as well.

Having the new ATA storage stack in place will translate into much better compatibility with real hardware, including the ability to use more hardware to install on and boot from compared to the old UniATA driver.

Combined, these two changes should bring the ReactOS installation and usage experience a lot closer to that of Windows, as well as many Linux distros. If you had issues with the OS on real hardware, this might be just the right time to give it another shake and provide detailed feedback to the developers if any remaining issues are encountered.

Thanks to [jeditobe] for the tip.

Software that collects public data from the Internet and uses it to provide half-assed answers to your questions might seem like a modern craze, but today we bid farewell to a website that helped pioneer pretend conversations all the way back in 1997 — as of May 1st, Ask Jeeves is no more.

Well, technically they dropped the “Jeeves” part back in 2006. Since then it’s just been Ask.com, but as the name implies the idea was more or less the same. Rather than the relatively rigid parameters and keywords required by traditional search engines, you could ask Jeeves questions about the world using natural language. Early advertisements showed the virtual valet answering arbitrary questions like “How many calories in a banana?,” which of course today seems commonplace and utterly unimpressive, but was a pretty wild for the 1990s.

It might seem surprising that a site designed from day one to offer a human-like Q&A experience should fold right as such technology is becoming commonplace. But of course, that commonality is the problem. When Google can answer your questions just as well (or poorly…) as Jeeves or anyone else, what’s the benefit for the average Internet user to seek out another service? But it’s still somewhat ironic, which is probably why the farewell message on Ask.com ends with the line “Jeeves’ spirit endures.”

While on the subject of technology that’s potentially ahead of its time, MacRumors is reporting that Apple is giving up on their Vision Pro augmented reality googles. They haven’t been formally discontinued as of yet, but sources indicate that the internal development team for the entire product line has been disbanded and reassigned to other projects within the company. This comes after a October 2025 refresh of the hardware still failed to connect with consumers. Insiders have said that not only were sales sluggish on the ~$3,500 headsets, but that they were getting returned at a far higher rate than any of Apple’s other hardware products.

Now, we’re hardly Apple apologists here at Hackaday. It sort of goes without saying that the whole “Walled Garden” thing doesn’t really fit our ethos. But we can’t deny that the Vision Pro is an impressive piece of technology. After years of sticking our phones in crappy plastic headsets, or trying to force hardware designed for VR gaming to do literally anything else, the Vision Pro offered a practical way to put augmented reality to work. But even for a company known for producing expensive hardware, the price tag was just too much for most consumers.

We’ll go out on a limb here and predict that the Vision Pro will one day be looked back on like the Newton — a product that was too expensive and niche to be a commercial success when it came out, but still a technical milestone that gave us a glimpse into the shape of things to come.

Speaking of a technology that will inevitably become more common, the European Patent Office (EPO) released a report this week showing a seven-fold increase in the number of inventions intended for battery reuse and recycling over the last decade. Given our insatiable demand for rechargeable batteries, it should come as no surprise that there’s a huge push for new methods of squeezing more use out of cells. As noted several times by the EPO, it’s not purely about saving money either. Even if Europe produces the batteries domestically, they need to import the raw materials. Relying on foreign countries to provide critical infrastructure can be precarious in the best of times, and is likely to only become more politically onerous in the future.

Finally, we’ll leave you with a fun way to waste some time on a Sunday evening: Visible Zorker. Created by Andrew Plotkin, this website allows you to not only play through all three installments of Zork, but presents a debugger-style view of the source code as the game is running. Even if you’re not terribly interested in seeing how your responses are parsed, the map that shows your progress through the world is certainly handy. The project was actually started back in 2025, but Andrew just completed the trilogy by adding support for Zork III a couple days ago so now is the perfect time to check it out.

See something interesting that you think would be a good fit for our weekly Links column? Drop us a line, we’d love to hear about it.

Triple monitor workstations are pretty common these days, particularly for those wishing to maximise screen space for greater productivity. [Will It Work?] has put together a sillier take on this concept, however, hooking the diminutive iPod Nano up to three monitors instead.

The 6th-generation iPod nano brought forth a new form factor – it’s the postage stamp-sized one that you could clip to your workout gear. It’s not typically what you’d call a productivity device, but there is a way to get more out of it. The trick is to grab a 30-pin Keyboard Dock, which allows access to the composite video signal from the iPod. It was originally designed for the iPad, but it works with the iPad nano too with a 30-pin spacer adapter – just don’t expect the keys to do anything. This setup also allows access to the 3.5mm four-pole jack, which handles audio input and output. With a bunch of additional cables and adapters, the iPod was able to be hooked up to three screens, a set of Apple Pro speakers, and three Sharp LCD monitors.

What can you do with this setup? Fundamentally, not a whole lot. You can’t use the keyboard with the iPod Nano, so you’re limited to interacting with the tiny touchscreen. There also aren’t exactly a lot of apps to run on the platform, either. You can basically listen to music, watch a slide show, or record voice memos, while looking at the iPod’s display spread identically across three TVs. Still, it’s a fun joke build, because at a glance it genuinely looks like you’ve set up a triple-monitor workstation running off a tiny iPod from over a decade ago.

If you want to blow the mind of your next podcast guest, consider recording your next episode on this rig. Alternatively, explore some of the other hacks we’ve seen for the platform. Video after the break.

There are plenty of photos of the International Space Station out there on the Internet, but taking your own from ground level is a special challenge. [saveitforparts] recently decided to attempt this feat using a $15 thrift store lens.

The cool thing about the digital photography revolution is that there is a lot of old film gear that can be had for cheap. In this case, [saveitforparts] found a 400mm Sigma XQ lens with a 2x teleconverter for just $14.99. Paired with an adapter, it sat nicely on a Sony NEX-3 digital camera, ready to try and capture the ISS as it passed overhead. As you might imagine, aiming at the space station is not a point-and-shoot job. N2YO.com was used to figure out the best time to try and capture it. [saveitforparts] was able to capture the ISS as a white dot as it passed over, but couldn’t quite get enough zoom to really see the ISS in detail.  [saveitforparts] was also able to repeat the feat with a Canon camcorder, too, but the image was still pretty blobby and didn’t show much. Later attempts involved capturing transits as the ISS passed by the Sun, though the ISS mostly appeared as a small speck.

[saveitforparts] did technically capture the ISS, just not closely enough to see much beyond a dot. It’s not the first time we’ve seen this attempted, though! If you try and capture the ISS with something truly ridiculous, like a Game Boy Camera or Kodak Charmera, you are honour-bound to tell us on the tipsline. Video after the break.

Peristaltic pumps are a very simple and effect device for transferring fluids without said fluid ever coming into contact with any part of the pump mechanism. At their core they involve a mechanism squeezing fluids through compressible tubing, but there are various implementations of such a mechanism that all have their pros and cons. In a recent article by [T. K. Hareendran] over at EDN these types are discussed and when you’d want to pick one over the other.

Also known as a roller pump, these positive displacement pumps have been known since the 19th century, finding uses in industrial, medical, research, agriculture and many other fields. Each of these fields have different requirements with the use of a peristaltic pump as a dosing pump being a specific application whereby e.g. a stepper motor can be used to provide exact dosing.

For industrial settings the typical rollers that compress the tube are replaced with shoes that provide higher pressures and endurance, with overall a bewildering number of motor types and tubing materials available. Depending on what your project needs, you may opt for continuous flow, fine control over dosing, the ability to reverse the flow, etc.

Unless your project is particularly rugged, a roller-based mechanism should be fine, while silicone tubing is great for biocompatibility and PVC is a cheaper tube material option. If you intend to transfer certain kinds of chemicals that will react with each of these there are some more exotic tubing options available as well.

We have previously covered projects that use a peristaltic pump for rather interesting things, such as DIY pharmaceutics, in a home-grown flow battery, not to mention creating DIY peristaltic pumps from first principles.

If you find yourself working with CANopen CC networks, you might find yourself in need of a tool for monitoring what’s happening on the wire. [Michael Fitzmayer] whipped up a piece of software to fulfil just that role. 

CANopenTerm might be named after the CANopen standard, but it’s really a terminal-driven tool for working with CAN buses in general. The software is built for real-time use, allowing sniffing raw frames on the wire, tracing, and probing of nodes, all from within the console. It’s also possible to add scripting via Lua or Python for more advanced work, as well as do protocol-aware inspection if that’s relevant to your use case. The key idea of the software is to be fast and scriptable to suit a given need, rather than bogging everything down with a heavy GUI interface that’s slower to work with.

If you aren’t afraid of getting into the nitty gritty with CAN and like lightweight text-based interfaces, this might be the tool for you. We’ve also explored some other CAN visualization tools lately, as well. Ultimately, there is a lot of machinery out there running on some variant of CAN or other, so it pays to know how to work with it. If you’ve got your own projects cooking up in this space, don’t hesitate to let us know on the tipsline!

C-3PO is one of the more famous movie robots out there. However, we don’t see a lot of replicas built, perhaps because in speech and mannerisms, he’s quite hard to replicate. Of course, that feat has become much more achievable with modern AI tech, as [Samuel Potozkin] demonstrates.

We’re not looking at a full C-3PO build here, it’s just the head—but for the project’s purposes, that’s all that was really required. The build relies on a Raspberry Pi 5 as the brains of the droid. It’s running a mic hooked up to a real time speech to text engine, and that text is then sent to a large language model for interpretation. Responses are then generated, passed through a processing layer to capture C-3PO’s general tone and vibe, and then handed off to a text-to-speech synth to imitate the iconic voice, played via speaker. The end result is a C-3PO you can actually talk to, which is something that might have knocked a few socks off when the movie first launched in 1977. In-depth materials for the build can be had via Google Drive and on Github.

This ersatz C-3PO isn’t an exact dupe of the movie ‘bot.  The protocol droid is a little slow to respond, and the patter isn’t quite on point, even if the voice synth makes a good effort at mimicking the original. Overall, it’s a little… robotic… something you wouldn’t say of the character in the movies. Still, it’s a great effort, and something we haven’t really seen much of before. If you like more classic droid replicas, though, we’ve featured those too. Video after the break.

Transistors in some circuit configurations work together and, frequently, need to be matched. This is so common that you can sometimes find ICs that are just a pair of transistors made with the same piece of silicon, so they should be matched very closely by default. But with discrete transistors, two devices of the same type are not always identical. [Learn Electronics Repair] covers the topic and explains how to match devices in the video below.

Depending on the circuit, the matching parameters may be different, but generally, the idea is that you want similar gains or matching saturation characteristics. The reason is that when you have multiple transistors working together, you don’t want one to do more work than the other device. This is inefficient and could drive the “better” component to fail.

The same idea applies in bridge circuits, where you might match resistors or capacitors to make sure that, for example, two 10% resistors are very close to the same value. A 10K resistor could be between 9K and 11K, and you might not care as long as they are both, say, 9.2K or both 10.8K.

This is different, by the way, from impedance matching, where you achieve maximum power transfer by matching a source to a load.

Once upon a time, someone set up a livestream wherein the messages from Twitch chat could control a game of Pokemon. Since then, we’ve seen Twitch control all sorts of things. If you’d like to have them play with some LEDs in your house, you might like this project from [pfeiffer3000].

The concept is simple enough. The heart of the build is an ESP32 microcontroller, which is easy to integrate with web services thanks to its onboard WiFi capability. It’s hooked upt o a string of WS2812B addressable RGB LEDs. The LEDs themselves are installed within table tennis balls to act as nice, spherical diffusers, and installed in a square frame made of PVC pipes. As for code, the rig uses the WLED library to drive the LED strings, and code from TwitchIO to interface with Twitch chat itself. It’s as simple as rigging up a bit of Python. With everything assembled, [pfeiffer3000] had an attractive LED grid that could be controlled directly by anyone watching their Twitch stream.

We’ve explored how to control things via Twitch before, too. It’s a fun way to add some interactivity to your livestream that really gets viewers involved. If you’ve been building your own audience-controlled projects, we’d love to hear about them on the tipsline!

Some people love CRTs to a degree that the uninitiated may find obsessive. We all have our thing, and for [Found Tech], it’s absolutely pointing particle accelerators at his face to play video games. He likes modern games, with modern resolutions– none of this 1080p nonsense. Today’s gamers demand 4K! Can a CRT keep up? The answer is a resounding “No, but actually, yes!”

[Found Tech] has an IBM P275 monitor, which is one of the last generation of CRTs.  Officially, the resolution maxes out at 1920 dots by 1440 lines. While one might (inaccurately) call that UHD output “2K”, you certainly cannot claim it is 4K. So, what’s the secret? Interlacing. Yes, interlacing, like old analog TV signals.

Apparently, in spite of what the manual says, getting the screen to absorb the 2880×2160 interlaced signal wasn’t the hard part, but generating it was. NVIDIA and AMD graphics cards are absolutely unable to create an interlaced signal, but Intel integrated GPUs are– if you get the right combo of chip and old driver. Sadly, the video doesn’t list exactly what he used. Of course an iGPU isn’t going to give you a very good gaming experience at this high resolution, so [Found Tech] has his games do their rendering on the discrete card before piping that over to the iGPU for display on the CRT.

Technically, you still can’t call the 2880×2160 picture “4K”, as that trademark refers to 2160p at 16:9, and this is both interlaced and 4:3. Still, close enough. In spite of the artifacting that turned us all against interlaced signals back in the day, this apparently has [Found Tech]’s eyes fooled– he says it’s as good as 2160p on his OLED, plus the extra magic that comes with glowing phosphors.

It certainly looks great in a recording, but the monitor in the recording isn’t displayed at a high enough resolution to say for sure if it’s 4K. Still, if you’re into CRT gaming, maybe give this high-res interlacing a try. If you still don’t get what’s so great about CRTs, check here, and remember it could be worse– at least we’re not going on about Plasma TVs.

Custom peripheral projects are among the most rewarding. Especially if you’re like me and you sit at the computer eight hours per day, anything that you can use on a daily basis is super satisfying. This topic of DIY peripherals came up on the podcast while chatting with Kristina, who is no stranger to odd inputs herself.

We were talking about a trackball that had been modified to read twisting gestures, by a clever hijacking of the twin mouse sensors inside. If you do a lot of 3D modeling, you can absolutely get by with just a mouse and shift-ctrl-alt as modifiers, but it’s so much more immediate to use a dedicated 3D input device. (I’ve got an ancient serial Space Mouse just under my left hand as I type this.)

My old favorite, which I haven’t used in ages, is the guts of a 5” hard-drive platter stack that I turned into a scroll wheel. Unfortunately, I don’t have space for it on my desk anymore, but it was just so pleasing to scroll through a document with something that had some real chonky momentum to it.

And it’s easier than ever to make your own. The classic blocky macropad is a great introduction, but as long as you’re doing the design yourself, why not extend it, or at least make it fit your hand? Or take your flights of fancy even further away from the mainstream. Consider the Bluetooth mouse ring, for instance.

Point is, the software side of almost any peripheral device you can imagine is sorted out already, and interfacing with the hardware is equally simple. Peripheral hacks have such a low barrier to entry, but afford so many creative hardware possibilities. And nothing says “Jedi” like building your own lightsaber.

Since the first electronic hobbyist wired up a multivibrator to a keyboard many decades ago, electonic synthesisers have been a staple of home-made projects. Now with the proliferation of significantly powerful microcontrollers it’s possible to make a synth that surpasses many of the high-end models from days gone by.

Among those we’ve seen of late perhaps none does this better than [Povle] with their Spark portable keyboard. It’s a tiny thing that reminds us of those little Casio synths of the 1980s, but in its 3D printed case it packs a load of features.

Hardware wise it’s an ESP32 with a 3D printed keyboard using keyswitches. There are a load of pots for sound adjustment, and buttons for functions. A small OLED display shows what’s going on. Software wise it relies upon the AMY synth library, and there are repositories for both its hardware and software.

There’s a demo video we’ve placed below, and in it you hear the keyboard at work. And here maybe we’ve saved the best until last, because alongside being a fully featured synth, it’s also a sampler and a Bluetooth MIDI keyboard. Is there nothing this thing can’t do!

After the Foucault pendulum at the Houston Museum of Natural Science stopped working a while back after maintenance on the building, workers set out to determine what was wrong with the mechanism that normally keeps it in motion. Fortunately, it turned out that all they had to do was fiddle with some knobs to get everything dialed back in proper-like.

When we previously covered this dire event, it was claimed that this was a one-off system, hacked together by some random bloke. But as can be seen in the video and further detailed in the comments to the video the reality is far more interesting.

This particular Foucault pendulum is one of many that were created by the California Academy of Sciences, with hundreds of them installed throughout the US and possibly elsewhere. That said, since a pendulum of any description will never be a perpetual motion device, the electromagnet installed near the top of the installation has to carefully add some kinetic energy back that was lost due to friction as the pendulum moves around.

Sadly the video doesn’t go into much detail on what exactly was wrongly configured with this particular pendulum. Keeping a weight at the end of a long cable moving around at a set velocity is a tricky business, so it’s little wonder that getting some parameters wrong would engage and disengage the electromagnets at the wrong times and making the pendulum stop swinging.

These days, even an old Game Boy will set you back $100 or more, and a new handheld console will be many multiples of that. However, you can build a really cheap handheld gaming toy if you follow [Chris Dell’s] example.

In [Chris]’s own words, he used Rust to build a $1 handheld gaming console. How is that possible? Well, it all comes down to the CH32V003—a microcontroller cheaper than just about anything else out there. It sells for just 9 cents in bulk, and it’s no slouch either. The RISC-V device is a fully-fledged 32-bit chip running at 48 MHz, though with only 2 KB of RAM and 16 KB of flash. Still, that’s more than enough to make some little games. To this end, [Chris] paired the CH32V003 with an SSD1306 OLED display, and three tactile pushbuttons. He then whipped up some code in Rust with the aid of the ch32-hal project, implementing a neat platform game that ran at a healthy 25 fps.

The CH32V003 probably won’t be starring in a new handheld gaming revolution anytime soon. Still, it’s always interesting to see just what can be achieved with one of the cheapest microcontrollers on the market.

[Thanks to Kian Ryan for the tip!]

The solar system is kind of hard to observe in motion all at once. Sometimes, it’s nice to have a little model to look at, so you can see the relative motions of celestial bodies play out in front of you. Such a device is called an orrery, and [illusionmanager] has built rather a nice example of their own.

The build represents all the planets in the solar system, plus the sun and our very own Moon. An ESP32 lives at the heart of the build, running an astronomical simulation to calculate the proper positions of all the celestial objects. It then drives a small stepper motor via a TMC2209 driver, turning the mechanism back and forth until all the pieces are positioned correctly, using a reed switch and magnet to detect the initial zero position. The orrery is able to be driven by a single motor in this manner thanks to an ingenious mechanism, wherein the rings interlock with each other using small tabs. The Moon is controlled by a separate geared mechanism connected to the main rotation.

It’ s a nice decoration that also serves as a great conversation piece, particularly if you like talking about the heavens. We’ve featured some fine works from [illusionmanager] before, too, like this exquisite reverse sundial. Video after the break.