2025-12-02 08:00:31
[Aditya Sripada] and [Abhishek Warrier]’s TARS3D robot came from asking what it would take to make a robot with the capabilities of TARS, the robotic character from Interstellar. We couldn’t find a repository of CAD files or code but the research paper for TARS3D explains the principles, which should be enough to inspire a motivated hacker.
What makes TARS so intriguing is the simple-looking structure combined with distinct and effective gaits. TARS is not a biologically-inspired design, yet it can walk and perform a high-speed roll. Making real-world version required not only some inspired mechanical design, but also clever software with machine learning.
[Aditya] and [Abhishek] created TARS3D as a proof of concept not only of how such locomotion can be made to work, but also as a way to demonstrate that unconventional body and limb designs (many of which are sci-fi inspired) can permit gaits that are as effective as they are unusual.
TARS3D is made up of four side-by-side columns that can rotate around a shared central ‘hip’ joint as well as shift in length. In the movie, TARS is notably flat-footed but [Aditya] found that this was unsuitable for rolling, so TARS3D has curved foot plates.
The rolling gait is pretty sensitive to terrain variations, but the walking gait proved to be quite robust. All in all it’s a pretty interesting platform that does more than just show a TARS-like dual gait robot can be made to actually work. It also demonstrates the value of reinforcement learning for robot gaits.
A brief video is below in which you can see the bipedal walk in action. Not that long ago, walking robots were a real challenge but with the tools available nowadays, even a robot running a 5k isn’t crazy.
2025-12-02 05:00:40
To those of us who live in the civilized lands where ~230 VAC mains is the norm and we can shove a cool 3.5 kW into an electric kettle without so much as a second thought, the mere idea of trying to boil water with 120 VAC and a tepid 1.5 kW brings back traumatic memories of trying to boil water with a 12 VDC kettle while out camping. Naturally, in a fit of nationalistic pride this leads certain North American people like that bloke over at the [Technology Connections] YouTube to insist that this is fine, as he tries to demonstrate how ridiculous 240 VAC kettles are by abusing a North American Level 2 car charger to power a UK-sourced kettle.
Ignoring for a moment that in Europe a ‘Level 1’ charger is already 230 VAC (±10%) and many of us charge EVs at home with three-phase ~440 VAC, this video is an interesting demonstration, both of how to abuse an EV car charger for other applications and how great having hot water for tea that much faster is.
Friendly tea-related transatlantic jabs aside, the socket adapter required to go from the car charger to the UK-style plug is a sight to behold. All which we starts as we learn that Leviton makes a UK-style outlet for US-style junction boxes, due to Gulf States using this combination. This is subsequently wired to the pins of the EV charger connector, after which the tests can commence.
Unsurprisingly, the two US kettles took nearly five minutes to boil the water, while the UK kettle coasted over the finish line at under two minutes, allowing any tea drinker to savor the delightful smells of the brewing process while their US companion still stares forlornly at their American Ingenuity in action.
Beginning to catch the gist of why more power now is better, the two US kettles were then upgraded to a NEMA 6-20 connector, rated for 250 VAC and 20 A, or basically your standard UK ring circuit outlet depending on what fuse you feel bold enough to stick into the appliance’s power plug. This should reduce boiling time to about one minute and potentially not catch on fire in the process.
Both of the kettles barely got a chance to overheat and boiled the water in 55 seconds. Unfortunately only the exposed element kettle survived multiple runs, and both found themselves on an autopsy table as it would seem that these kettles are not designed to heat up so quickly. Clearly a proper fast cup of tea will remain beyond reach of the average North American citizen beyond sketchy hacks or using an old-school kettle.
Meanwhile if you’d like further international power rivalry, don’t forget to look into the world as seen through its power connectors.
2025-12-02 03:30:41
Playing the drums requires a lot of practice, but that practice can be incredibly loud. A nice workaround is presented by [PocketBoy], in converting an acoustic kit to electronic operation so you can play with headphones instead.
It might sound like a complicated project, but creating a basic set of electronic drums can actually be quite simple if you’ve already got an acoustic kit. You just need to damp all the drums and cymbals to make them quieter, and then fit all the individual elements with their own piezo sensors. These are basically small discs that can pick up vibrations and turn them into electricity—which can be used to trigger an electronic drum module.
[PocketBoy]’s build started with a PDP New Yorker kit, some mesh heads to dull the snares and toms, and some low-volume cymbals sourced off Amazon. Each drum got a small piezo element, which was soldered to a 6.5mm jack for easy hookup. They’re installed inside the drums on foam squares with a simple bracket system [PocketBoy] whipped up from hardware store parts. A DDrum DDti interface picks up the signals from the piezo elements and sends commands to an attached PC. It’s paired with Ableton 12 Lite, which plays the drum sounds as triggered by the drummer.
[PocketBoy] notes it’s a quick and dirty setup, good for quiet practice but not quite gig-ready. You’d want to probably just run it as a regular acoustic kit in that context, but there’s nothing about the conversion that prevents that. Ultimately, it’s a useful project if you find yourself needing to practice the drums quietly and you don’t have space for a second electric-only kit. There’s lots of other fun you can have with those piezos, too. Video after the break.
@the606queer How I’m getting away with a drumset in an apartment building! Mesh heads + DIY triggers + Plain wash cloth + Stick Rods + DDTI DDrum Trigger i/o into Ableton. I need a better snare sample but this thing is whisper quiet! #drums #beginner #acoustics #fyp #drumtok
2025-12-02 02:00:46
Asbestos is a nasty old mineral. It’s known for releasing fine, microscopic fibers that can lodge in the body’s tissues and cause deadly disease over a period of decades. Originally prized for its fire resistance and insulating properties, it was widely used in all sorts of building materials. Years after the dangers became clear, many countries eventually banned its use, with strict rules around disposal to protect the public from the risk it poses to health.
Australia is one of the stricter countries when it comes to asbestos, taking great pains to limit its use and its entry into the country. This made it all the more surprising when it became apparent that schools across the nation had been contaminated with loose asbestos material. The culprit was something altogether unexpected, too—in the form of tiny little tubes of colored sand. Authorities have rushed to shut down schools as the media asked the obvious question—how could this be allowed to happen?
Australia takes asbestos very seriously. Typically, asbestos disposal is supposed to occur according to very specific rules. Most state laws generally require that the material must be collected by qualified individuals except in minor cases, and that it must be bagged in multiple layers of plastic prior to disposal to avoid release of dangerous fibers into the environment. The use, sale, and import of asbestos has been outright banned since 2003, and border officials enforce strict checks on any imports deemed a high risk to potentially contain the material.
Thus, by and large, you would expect that any item you bought in an Australian retailer would be free of asbestos. That seemed to be true, until a recent chance discovery. A laboratory running tests on some new equipment happened to accidentally find asbestos contamination in a sample of colored sand—a product typically marketed for artistic use by children. The manager of the lab happened to mention the finding in a podcast, with the matter eventually reaching New Zealand authorities who then raised the alarm with their Australian counterparts. This led to a investigation by the Australian Competition and Consumer Commission (ACCC), which instituted a national safety recall in short order.
The response from there was swift. At least 450 schools instituted temporary shutdowns due to the presence or suspected presence of the offending material. Some began cleanup efforts in earnest, hiring professional asbestos removalists to deal with the colored sand. In many cases, the sand wasn’t just in sealed packaging—it had been used in countless student artworks or spilled in carpeted classrooms. Meanwhile, parents feared the worst after finding the offending products in their own homes. Cleanup efforts in many schools are ongoing, due in part to the massive spike in demand for the limited asbestos removal services available across the country. Authorities in various states have issued guidelines on how to handle cleanup and proper disposal of any such material found in the workplace.
At this stage, it’s unclear how asbestos came to contaminate colored sand products sold across the country, though links have been found to a quarry in China. It’s believed that the products in question have been imported into Australia since 2020, but have never faced any testing regarding asbestos content. Different batches have tested positive for both tremolite and chrysotile asbestos, both of which present health risks to the public. However, authorities have thus far stated the health risks of the colored sand are low. “The danger from asbestos comes when there are very, very fine fibres that are released and inhaled by humans,” stated ACCC deputy chair, Catriona Lowe. “We understand from expert advice that the risk of that in relation to these products is low because the asbestos is in effect naturally occurring and hasn’t been ground down as such to release those fibres.”
Investigations are ongoing as to how asbestos-containing material was distributed across the country for years, and often used by children who might inhale or ingest the material during use. The health concerns are obvious, even if the stated risks are low. The obvious reaction is to state that the material should have been tested when first imported, but such a policy would have a lot of caveats. It’s simply not possible to test every item that enters the country for every possible contaminant. At the same time, one could argue that a mined sand product is more likely to contain asbestos than a box of Hot Wheels cars or a crate of Belgian chocolates. A measured guess would say this event will be ruled out as a freak occurrence, with authorities perhaps stepping up random spot checks on these products to try and limit the damage if similar contamination occurs again in future.
Featured image and other sand product images from the Australian government’s recall page.
2025-12-02 00:30:05
[Slant 3D] has a useful video explaining some thoughtful CAD techniques for designing 3D printed pins that don’t break and the concepts can be extended to similar features.
Sure, one can make pins stronger simply by upping infill density or increasing the number of perimeters, but those depend on having access to the slicer settings. If someone else is printing a part, that part’s designer has no actual control over these things. So how can one ensure sturdier pins without relying on specific print settings? [Slant 3D] covers two approaches.
The first approach includes making a pin thick, making it short (less leverage for stress), and adding a fillet to the sharp corner where the pin meets the rest of the part. Why? Because a rounded corner spreads stress out, compared to a sharp corner.
Those are general best practices, but there’s even more that can be done with microfeatures. These are used to get increased strength as a side effect of how a 3D printer actually works when making a part.
One type of microfeature is to give the pin a bunch of little cutouts, making the cross-section look like a gear instead of a circle. The little cutouts don’t affect how the pin works, but increase the surface area of each layer, making the part stronger.
A denser infill increases strength, too. Again, instead of relying on slicer settings, one can use microfeatures for a similar result. Small slots extending down through the pin (and going into the part itself) don’t affect how the part works, but make the part sturdier. Because of how filament-based 3D printing works, these sorts of features are more or less “free” and don’t rely on specific printer or slicer settings.
[Slant 3D] frequently shares design tips like this, often focused on designing parts that are easier and more reliable to print. For example, while printers are great at generating useful support structures, sometimes it’s better and easier in the long run to just design supports directly into the part.
2025-12-01 23:00:38
As amazing as the human body is, it’s unfortunately not as amazing as e.g. axolotl bodies are, in the sense that they can regrow entire limbs and more. This has left us humans with the necessity to craft artificial replacement limbs to restore some semblance of the original functionality, at least until regenerative medicine reaches maturity.
Despite this limitation, humans have become very adept at crafting prosthetic limbs, starting with fairly basic prosthetics to fully articulated and beautifully sculpted ones, all the way to modern-day functional prosthetics. Yet as was the case a hundred years ago, today’s prosthetics are anything but cheap. This is mostly due to the customization required as no person’s injury is the same.
When the era of 3D printing arrived earlier this century, it was regularly claimed that this would make cheap, fully custom prosthetics a reality. Unfortunately this hasn’t happened, for a variety of reasons. This raises the question of whether 3D printing can at all play a significant role in making prosthetics more affordable, comfortable or functional.
The requirements for a prosthetic depend on the body part that’s affected, and how much of it has been lost. In the archaeological record we can find examples of prosthetics dating back to around 3000 BCE in Ancient Egypt, in the form of prosthetic toes that likely were mostly cosmetic. When it came to leg prosthetics, these would usually be fashioned out of wood, which makes the archaeological record here understandably somewhat spotty.
While Pliny the Elder made mention of prosthetics like an iron hand for a general, the first physical evidence of a prosthetic for a lost limb are found in the form of items such as the Roman Capua Leg, made out of metal, and a wooden leg found with a skeleton at the Iron Age-era Shengjindian cemetery that was dated to around 300 BCE. These prosthetics were all effectively static, providing the ability to stand, walk and grip items, but truly functional prosthetics didn’t begin to be developed until the 16th century.
These days we have access to significantly more advanced manufacturing methods and materials, 3D scanners, and the ability to measure the electric currents produced by muscles to drive motors in a prosthetic limb, called myoelectric control. This latter control method can be a big improvement over the older method whereby the healthy opposing limb partially controls the body-powered prosthetic via some kind of mechanical system.
All of this means that modern-day prosthetics are significantly more complex than a limb-shaped piece of wood or metal, giving some hint as to why 3D printing may not produce quite the expected savings. Even historically, the design of functional prosthetic limbs involved complex, fragile mechanisms, and regardless of whether a prosthetic leg was just static or not, it would have to include some kind of cushioning that matched the function of the foot and ankle to prevent the impact of each step to be transferred straight into the stump. After all, a biological limb is much more than just some bones that happen to have muscles stuck to them.
Perhaps the most important part of a prosthetic is the interface with the body. This one element determines the comfort level, especially with leg prostheses, and thus for how long a user can wear it without discomfort or negative health impacts. The big change here has been largely in terms of available materials, with plastics and similar synthetics replacing the wood and leather of yesteryear.
Generally, the first part of fitting a prosthetic limb involves putting on the silicone liner, much like one would put on a sock before putting on a shoe. This liner provides cushioning and creates an interface with the prosthesis. For instance, here is an instruction manual for just such a liner by Össur.
These liners are sized and trimmed to fit the limb, like a custom comfortable sock. After putting on the liner and adding an optional distal end pad, the next step is to put on the socket to which the actual prosthetic limb is attached. The fit between the socket and liner can be done with a locking pin, as pictured on the right, or in the case of a cushion liner by having a tight seal between the liner and socket. Either way, the liner and socket should not be able to move independently from each other when pulled on — this movement is called “pistoning”.
For a below-knee leg prosthesis the remainder of the device below the socket include the pylon and foot, all of which are fairly standard. The parts that are most appealing for 3D printing are this liner and the socket, as they need to be the most customized for an individual patient.
Companies like the US-based Quorum Prosthetics do in fact 3D print these sockets, and they claim that it does reduce labor cost compared to traditional methods, but their use of an expensive commercial 3D printer solution means that the final cost per socket is about the same as using traditional methods, even if the fit may be somewhat better.
This highlights perhaps the most crucial point about using 3D printing for prosthetics: to make it truly cheaper you also have to lean into lower-tech solutions that are accessible to even hobbyists around the world. This is what for example Operation Namaste does, with 3D printed molds for medical grade silicone to create liners, and their self-contained Limbkit system for scanning and printing a socket on the spot in PETG. This socket can be then reinforced with fiberglass and completed with the pylon and foot, creating a custom prosthetic leg in a fraction of the time that it would typically take.
Founder of Operation Namaste, Jeff Erenstone, wrote a 2023 article on the hype and reality with 3D printed prosthetics, as well as how he got started with the topic. Of note is that the low-cost methods that his Operation Namaste brings to low-resource countries in particular are not quite on the same level as a prosthetic you’d get fitted elsewhere, but they bring a solution where previously none existed, at a price point that is bearable.
Merging this world with that of of Western medical systems and insurance companies is definitely a long while off. Additive manufacturing is still being tested and only gradually integrated into Western medical systems. At some level this is quite understandable, as it comes with many asterisks that do not exist in traditional manufacturing methods.
It probably doesn’t bear reminding that having an FDM printed prosthetic snap or fracture is a far cry from having a 3D printed widget do the same. You don’t want your bones to suddenly go and break on you, either, and faulty prosthetics are a welcome source of expensive lawsuits in the West for lawyers.
Beyond liners and sockets there is much more to prosthetic limbs, as alluded to earlier. Myoelectric control in particular is a fairly recent innovation that detects the electrical signals from the activation of skeletal muscles, which are then used to activate specific motor functions of a prosthetic limb, as well as a prosthetic hand.
The use of muscle and nerve activity is the subject of a lot of current research pertaining to prosthetics, not just for motion, but also for feedback. Ideally the same nerves that once controlled the lost limb, hand or finger can be reused again, along with the nerves that used to provide a sense of touch, of temperature and more. Whether this would involve surgical interfacing with said nerves, or some kind of brain-computer interface is still up in the air.
How this research will affect future prosthetics remains to be seen, but it’s quite possible that as artificial limbs become more advanced, so too will the application of additive manufacturing in this field, as the next phase following the introduction of plastics and other synthetic materials.
