Fresh from AliExpress, [Big Clive] got another fascinating item to tear down: a crane claw, as used in those all too familiar carnival games. These games feature a claw the player moves into position above a pile of toys or other items. Lower the claw gently down in the hopes that it grabs the target item. In a perfect world, the claw will move your prize and deposit it, via a chute, into your waiting hands. Of course, everyone knows that these games are rigged and rely less on skill or luck than the way that they are programmed, but the way that this works is quite subtle, as you can see in the video below.

Despite how complex these crane claws may appear, they are simply solenoids, with the metal rod inside providing the claw action. The weight of the rod and claw section opens the claw via gravity. The strength of the claw is thus fully dependent on how strongly the solenoid is being driven, which, as [Clive] demonstrates, depends on the voltage and the duty cycle. At only 12V, the target plushie will easily slip away again as the claw barely has any strength, while at 24V, it’s pretty solid.

The basic way these crane games are programmed is to use a voltage and/or duty cycle that depends on the amount of money spent (in credits) and the monetary value of the items you can ‘win.’ If you’re very lucky you’ll get a solid catch even with a floppy claw. Most of the time you’ll have to wait until you get a solid claw. While a simple concept, it seems more designed to game the player. As [Clive] duly notes, just buying the item will probably save you a lot of money and frustration.

Or, build your own, of course. There are plenty of examples.

Owing to the wave nature of light there are many ways that such different waves can interact with each other, but also with materials. Everyone knows about reflecting light with a mirror, which is a property of materials like metals, but specific structures can cause the light to behave in a way that creates rather amazing results.

Examples of this are cases of iridescence in nature (like butterfly wings) and eye color, where the perceived colors are the result of environmental light interacting with these structures rather than pigmentation or dyes. An even more interesting interaction has now been demonstrated by reflecting multiple microwave radiation beams off each other, creating a time reflection.

The study by [Emanuele Galiffi] et al. (shared copy) was published in Nature Physics. By creating a metamaterial that allows for temporal coherent wave control (CWC) the electromagnetic radiation was controlled to where it allowed for this kind of unusual interaction. The key here being that there is no major constructive or destructive interaction between the two waves as with spatial CWC, rather the wave reflect off each other, or more specifically the time interface.

Although the popular reporting talks about ‘turning back time’ and ‘watching the back of your own head in a mirror’, the impact is far less dramatic: in the article conclusion the researchers mention unveiling new light-matter interactions in the microwave- and other parts of the spectrum, as well as new ways to control and shape light.

Top image: Temporal coherent wave control and photonic collisions enabled by time-interfaces. (Credit: Emanuele Galiffi et al., Nature Physics, 2023)

When [Tahmid Mahbub] recently reached for his ‘Lavolta’ BPS-305 bench supply, he was dismayed to find that despite it being a 30V, 5A-rated unit, the supply refused to output more than 15V. To be fair, he wasn’t sure that he had ever tried to push it beyond 15V in the years that he had owned it, but it had better live up to its specs. Ergo out came the screwdriver to open the power supply to see what had broken, and hopefully to fix it.

After some more probing around, he discovered that the unit had many more issues, including a highly unstable output voltage and output current measurement was completely wrong. Fortunately this bench power supply turns out to be very much like any number of similar 30V, 5A units, with repair videos and schematics available.

While [Tahmid] doesn’t detail his troubleshooting process, he does mention the culprits: two broken potentiometers (VR104 and VR102). VR104 is a 5 kOhm pot in the output voltage feedback circuit and VR102 (500 Ohm) sets the maximum output current. With no 500 Ohm pot at hand, a 5 kOhm one was combined with a 470 Ohm resistor to still allow for trimming. Also adjusted were the voltage and current trimpots for the front display as they were quite a bit off. Following some testing on the reassembled unit, this power supply is now back in service, for the cost of two potentiometers and a bit of time.

Within our comfortable world of causality we expect that reactions always follow an action and not vice versa. This why the recent chatter in the media about researchers having discovered ‘negative time’ with photons being emitted before the sample being hit by source photons created such a stir. Did these researchers truly just crack our fundamental concepts of (quantum) physics wide open? As it turns out, not really.

Much of the confusion stems from the fact that photons aren’t little marbles that bounce around the place, but are an expression of (electromagnetic) energy. This means that their resulting interaction with matter (i.e. groupings of atoms) is significantly more complicated, often resulting in the photonic energy getting absorbed by an atom, boosting the energy state of its electron(s) before possibly being re-emitted as the excited electrons decay into a lower orbit.

This dwell time before re-emission is what is confusing to many, as in our classical understanding we’d expect this to be a very deterministic process, while in a quantum world it most decidedly is not.

This is highlighted in the Scientific American article on the subject as well, specifically quantum probability. Within this system, it’s possible that there can be re-emissions before the atomic excitation has fully ceased. It was this original 2022 finding that was recently retested, with the findings confirmed.

As confusing as this all may sound, the authors of the recent paper stress that the core of the issue here is the so-called ‘group delay’ of the original pulse as it excites the cloud of rubidium atoms. If one were to think of this pulse as discrete quanta of photon particles, it’d seem to break causality, but as a wave function within quantum physics this is perfectly acceptable. Observations such as the rubidium atoms becoming excited despite photons passing through the cloud, and emitting a photon before the electrons returned to their ground state do not seem to make sense, but here we also have to consider how and what we are measuring.

The short version is that causality remains unbroken, and the world of quantum physics is intuitive in its own, strange ways. Research like this also gives us a much better fundamental understanding of photonics and related fields, none of which involve time travel.

Experimental setup and measured optical depth. (Credit: Josiah Sinclair et al., PRX Quantum, 2022)

Family Solanum (nightshade) is generally associated with toxins, and for good reasons, as most of the plants in this family are poisonous. This includes some of everyone’s favorite staple vegetables: potatoes, tomatoes and eggplant, with especially potatoes responsible for many poisonings each year. In the case of harvested potatoes, the chemical responsible (steroidal glycoalkaloids, or SGA) is produced when the potato begins to sprout. Now a team of researchers at the University of California have found a way to silence the production of the responsible protein: GAME15.

The research was published in Science, following earlier research by the Max Planck Institute. The researchers deleted the gene responsible for GAME15 in Solanum nigrum (black nightshade) to confirm that the thus modified plants produced no SGA. In the case of black nightshade there is not a real need to modify them as – like with tomatoes – the very tasty black berries they produce are free of SGA, and you should not eat the SGA-filled and very bitter green berries anyway, but it makes for a good test subject.

Ultimately the main benefits of this research appear to be in enriching our general understanding of these self-toxicity mechanisms of plants, and in making safer potatoes that can be stored without worries about them suddenly becoming toxic to eat.

Top image: Different potato varieties. (Credit: Scott Bauer, USDA ARS)

Being able to 3D print FDM objects in more than one color is a feature that is rapidly rising in popularity, assisted by various multi-filament systems that allow the printer to swap between differently colored filaments on the fly. Naturally, this has the disadvantage of being limited in the number of colors, as well as wasting a lot of filament with a wipe tower and filament ‘poop’. What if you could print color on the object instead? That’s basically what the community-made PolyDye project does, which adds an inkjet cartridge to an existing FDM printer.

In the [Teaching Tech] video the PolyDye technology is demonstrated, which currently involves quite a few steps to get the colored 3D model from the 3D modelling program into both OrcaSlicer (with custom profile) and the inkjet printing instructions on the PolyDye SD card. After this the 3D object will be printed pretty much as normal, just with each layer getting a bit of an ink shower.

Although it could theoretically work with any FDM printer, currently it’s limited to Marlin-based firmware due to some prerequisites. The PolyDye hardware consists of a main board, daughter board, printed parts (including inkjet cartridge holder) and some wiring. A Beta Test unit is available for sale for $199, but you should be able to DIY it with the files that will be added to the GitHub project.

Even for a work-in-progress, the results are quite impressive, considering that it only uses off-the-shelf translucent filament and inkjet cartridges as consumables. With optimizations, it could give multi-filament printing a run for its money.

Among the current challenges with creating quantum computers is that the timespan that a singular qubit remains coherent is quite limited, restricting their usefulness. Usually such qubits consist of an electromagnetic resonator (boson), which have the advantage of possessing discrete energy states that lend themselves well to the anharmonicity required for qubits. Using mechanical resonators would be beneficial due to the generally slower decoherence rate, but these have oscillations (phonons) that are harmonic in nature. Now researchers may have found a way to use both electromagnetic qubits and mechanical resonators to create a hybrid form that acts like a mechanical qubit, with quite long (200 µs) coherence time.

As per the research paper by [Yu Yang] and colleagues in Science (open access preprint), their experimental mechanical qubit (piezoelectric disc and superconducting qubit on sapphire) was able to be initialized and read out, with single-qubit gates demonstrated. The experimental sequence for the phonon anharmonicity measurement is shown in the above image (figure 2 in the paper), including the iSWAP operations which initialize the hybrid qubit. Effectively this demonstrates the viability of such a hybrid, mechanical qubit, even if this experimental version is not impressive yet compared to the best electromagnetic qubit. Those have managed to hit a coherence time of 1 ms.

The lead researcher, [Yu Yang] expresses his confidence that they can improve this coherence time with more optimized designs and materials, with future experiments likely to involve more complex quantum gates as well as sensor designs.

What do you do when a crowdfunded product you really liked gets cancelled? Naturally, you take the idea and build your own version of it. That’s what [Salim Benbouziyane] did when the TimeChi project on Kickstarter saw its launch cut short. This device allows you to set a ‘no distractions’ timer, during which notifications on one’s phone and elsewhere are disabled, making it something similar to those Pomodoro timers. What this dial also is supposed to do is integrate with home automation to set up clear ‘focus’ periods while the timer runs.

A quick prototype of the newly minted Focus Dial project was set up using an ESP32 and other off-the-shelf components. The firmware has to run the timer, toggle off notifications on iOS and trigger firewall traffic rules to block a batch of social media addresses. Automating this with iOS was the hardest part, as Apple doesn’t make such automation features easy at all, ultimately requiring a Bluetooth audio board just to make iOS happy.

After this prototyping phase, the enclosure and assembly with the modules were drawn up in Autodesk Fusion 360 before the plastic parts were printed with a resin printer. The end result looks about as good as the Kickstarter one did, but with a few changes, because as [Salim] notes, if you are going to DIY such a failed crowdfunding project, why not make it work better for you?

An unfortunate reality of pre-1990s computer systems is that any manuals and documentation that came with them likely only existed on paper. That’s not to say there aren’t scanned-in (PDF) copies of those documents floating around, but with few of these scans being indexable by search engines like Google and Duck Duck Go, they can be rather tricky to find. That’s where the Manx catalog website seeks to make life easier. According to its stats, it knows about 22,060 manuals (9,992 online) across 61 websites, with a focus on minicomputers and mainframes.

The code behind Manx is GPL 2.0 licensed and available on GitHub, which is where any issues can be filed too. While not a new project by any stretch of the imagination, it’s yet another useful tool to find a non-OCR-ed scan of the programming or user manual for an obscure system. As noted in a recent Hacker News thread, the ‘online’ part of the above listed statistics means that for manuals where no online copy is known, you get a placeholder message. Using the Bitsavers website along with Archive.org may still be the most pertinent way to hunt down that elusive manual, with the Manx website recommending 1000bit for microcomputer manuals.

Have you used the Manx catalog, or any of the other archiving websites? What have been your experiences with them? Let us know in the comments.

Although the US’ Moon landings were mostly made famous by the fact that it featured real-life human beings bunny hopping across the lunar surface, they weren’t there just for a refreshing stroll over the lunar regolith in deep vacuum. Starting with an early experimental kit (EASEP) that was part of the Apollo 11 mission, the Apollo 12 through Apollo 17 were provided with the full ALSEP (Apollo Lunar Surface Experiments Package). It’s this latter which is the subject of a video by [Our Own Devices].

Despite the Apollo missions featuring only one actual scientist (Harrison Schmitt, geologist), these Bendix-manufactured ALSEPs were modular, portable laboratories for running experiments on the moon, with each experiment carefully prepared by scientists back on Earth. Powered by a SNAP-27 radioisotope generator (RTG), each ALSEP also featured the same Central Station command module and transceiver. Each Apollo mission starting with 12 carried a new set of experimental modules which the astronauts would set up once on the lunar surface, following the deployment procedure for that particular set of modules.

Although the connection with the ALSEPs was terminated after the funding for the Apollo project was ended by US Congress, their transceivers remained active until they ran out of power, but not before they provided years worth of scientific data on many aspects on the Moon, including its subsurface characteristics and exposure to charged particles from the Sun. These would provide most of our knowledge of our Moon until the recent string of lunar landings by robotic explorers.

Heading image: Apollo Lunar Surface Experiments Package of the Apollo 16 mission (Credit: NASA)

Altermagnetism is effectively a hybrid form of ferromagnetism and antiferromagnetism that might become very useful in magnetic storage as well as spintronics in general. In order to practically use it, we first need to be able to control the creation of these altermagnets, which is what researchers have now taken the first steps towards. The research paper by [O. J. Amin] et al. was published earlier this month in Nature. It builds upon the team’s earlier research, including the detection of altermagnetism in manganese telluride (MnTe). This new study uses the same material but uses a photoemission electron microscope (PEEM) with X-rays to image these nanoscale altermagnetic structures.

Additionally, the spin orientation of these altermagnetic structures within the MnTe was controlled using microstructure patterning and thermal cycling in magnetic fields. The micropatterning with electron beam lithography enabled the creation of large single-domain altermagnetic structures, which is promising for further research. As noted in the outlook section by the researchers, this part of the research is still very much about creating the basic means to use altermagnetism, even for something as seemingly straightforward as data storage. In this particular study, the reading (imaging) mechanism was an expensive PEEM setup with the X-rays produced by a synchrotron.

Honestly, we still struggle to figure out plain old magnetism. Obviously, there’s more to it than that.

Heading image: Illustrative models of collinear ferromagnetism, antiferromagnetism, and altermagnetism in crystal-structure real space and nonrelativistic electronic-structure momentum space. (Credit: Libor Šmejkal et al., Phys. Rev. X, 2022)

The Sinclair ZX Spectrum+2 was the first home computer released by Amstrad after buying up Sinclair. It’s basically a Sinclair ZX Spectrum 128, but with a proper keyboard and a built-in tape drive. The one that [Mark] of the Mend it Mark YouTube channel got in for repair is however very much dead. Upon first inspection of the PCB, it was obvious that someone had been in there before, replacing the 7805 voltage regulator and some work on other parts as well, which was promising. After what seemed like an easy fix with a broken joint on the 9 VDC input jack, the video output was however garbled, leading to the real fault analysis.

Fortunately these systems have full schematics available, allowing for easy probing on the address and data lines. Based on this the Z80 CPU was swapped out to eliminate a range of possibilities, but this changed nothing with the symptoms, and a diagnostic ROM cartridge didn’t even boot. Replacing a DS74LS157 multiplexer and trying different RAM chips also made no difference. This still left an array of options on what could be wrong.

Tracking down one short with an IC seemed to be a break, but the video output remained garbled, leaving the exciting possibility of multiple faults remaining. This pattern continues for most of the rest of the video, as through a slow process of elimination the bugs are all hunted down and eliminated, leaving a revived Spectrum+2 (and working tape drive) in its wake, as well as the realization that even with all through-hole parts and full schematics, troubleshooting can still be a royal pain.

Extremophile lifeforms on Earth are capable of rather astounding feats, with the secret behind the extreme radiation resistance of one of them now finally teased out by researchers. As one of the most impressive extremophiles, Deinococcus radiodurans is able to endure ionizing radiation levels thousands of times higher than what would decisively kill a multicellular organism like us humans. The trick is the antioxidant which this bacterium synthesizes from multiple metabolites that combine with manganese. An artificial version of this antioxidant has now been created that replicates the protective effect.

The ternary complex dubbed MDP consists of manganese ions, phosphate and a small peptide, which so far has seen application in creating vaccines for chlamydia. As noted in a 2023 study in Radiation Medicine and Protection by [Feng Liu] et al. however, the D. radiodurans bacterium has more survival mechanisms than just this antioxidant. Although much of the ionizing radiation is neutralized this way, it can not be fully prevented. This is where the highly effective DNA repair mechanism comes into play, along with a range of other adaptations.

The upshot of this is the synthesis of a very effective and useful antioxidant, but as alluded to in the press releases, just injecting humans with MDP will not instantly give them the same super powers as our D. radiodurans buddy.

Featured image: Survival mechanisms in Deinococcus radiodurans bacterium. (Credit: Feng Liu et al., 2023)

If you ever wanted to dive into the source code for the 1980s space game Elite, but didn’t want to invest many hours reverse-engineering the 6502 assembly code, then [Mark Moxon]’s annotated code has you covered. The systems referenced range from the BBC Micro and Commodore 64 to the NES and Apple II, with some of these versions based on the officially released source code. For other systems the available source code was used together with decompiled game binaries to determine the changes and to produce functional, fully commented source code.

This particular game is fascinating for being one of the first to use wire-frame 3D graphics with hidden-line removal and a sprawling universe in which to trade and deal with less than friendly parties using a variety of weapons. After this initial entry it would go on to spawn many sequels and inspired countless games that’d follow a similar formula.

On the respective GitHub project page for each version, you can find instructions on how to build the code for yourself, such as for the Commodore 64. Of note here is the license, which precludes anyone from doing more than forking and reading the code. If this is no concern, then building the game is as simple as using the assembler (BeebAsm) and the c1541 disk image utility from the VICE project.

Google’s Chromecast was first released in 2013, with a more sophisticated follow-up in 2015, which saw itself joined by the Chromecast Audio dongle. The device went through an additional two hardware generations before the entire line of products was discontinued earlier this year in favor of Google TV.

In addition to collecting each generation of Chromecast, [Brian Dipert] over at EDN looked back on this second-generation dongle from 2015 while also digging into the guts of a well-used example that got picked up used.

While not having any of the fascinating legacy features of the 2nd-generation Ultra in his collection that came with the Stadia gaming controller, it defines basically everything that Chromecast dongles were about: a simple dongle with a HDMI & USB connector that you plugged into a display that you wanted to show streaming content on. The teardown is mostly similar to the 2015-era teardown by iFixit, who incidentally decided not to assign any repairability score, for obvious reasons.

Most interesting about this second-generation Chromecast is that the hardware supported Bluetooth, but that this wasn’t enabled until a few years later, presumably to fix the wonky new device setup procedure that would be replaced with a new procedure via the Google Home app.

While Google’s attention has moved on to newer devices, the Chromecast isn’t dead — the dongles in the wild still work, and the protocol is supported by Google TV and many ‘smart’ appliances including TVs and multimedia receivers.

Hobbyist 3D printers have traditionally run the open source Marlin and later Klipper firmware, but as some hobbyists push their printers to the limits, more capable and less conservative firmware was needed. This is why the aptly named ‘Danger-Klipper’ fork of the Klipper firmware comes with the motto ‘I should be able to light my printer on fire’. Because the goal of Danger-Klipper wasn’t literally to light printers on fire (barring unfortunate accidents), the project has now been renamed to Kalico by the developers, after the pirate Calico Jack to maintain the nautical theming.

Not only does the project get a new name, but also a cute new pirate-themed calico cat logo. Beyond these changes not much else is different, though the documentation is obviously now also at a new domain. As a Klipper fork just about any printer that can run Klipper should be able to run Kalico, though the focus is on Raspberry Pi 2, 3 or 4. The FAQ has some more details on what Kalico can run on. Obviously, Kalico makes for a great option if you are building your own customized 3D printer (or similar), and will support the typical web UIs like Fluidd, OctoPrint, etc.

For some of the differences between Klipper and Kalico, the ‘Danger Features’ section of the documentation provides an impression. Suffice it to say that Kalico is not the kind of firmware to hold your hand or provide guiderails, making it an option for advanced users for whom breaking things while pushing boundaries is just part of the hobby.

Thanks to [Vinny] for the tip.

The cable car system of San Francisco is the last manually operated cable car system in the world, with three of the original twenty-three lines still operating today. With these systems being installed between 1873 and 1890, they were due major maintenance and upgrades by the time the 1980s and with it their 100th year of operation rolled around. This rebuilding and upgrading process was recorded in a documentary by a local SF television station, which makes for some fascinating viewing.

While the cars themselves were fairly straight-forward to restore, and the original grips that’d latch onto the cable didn’t need any changes. But there were upgrades to the lubrication used (originally pine tar), and the powerhouse (the ‘barn’) was completely gutted and rebuilt.

As opposed to a funicular system where the cars are permanently attached to the cable, a cable car system features a constantly moving cable that the cars can grip onto at will, with most of the wear and tear on the grip dies. Despite researchers at San Francisco State University (SFSU) investigating alternatives, the original metal grip dies were left in place, despite their 4-day replacement schedule.

Ultimately, the rails and related guides were all ripped out and replaced with new ones, with the rails thermite-welded in place, and the cars largely rebuilt from scratch. Although new technologies were used where available, the goal was to keep the look as close as possible to what it looked at the dawn of the 20th century. While more expensive than demolishing and scrapping the original buildings and rolling stock, this helped to keep the look that has made it a historical symbol when the upgraded system rolled back into action on June 21, 1984.

Decades later, this rebuilt cable car system is still running as smoothly as ever, thanks to these efforts. Although SF’s cable car system is reportedly mostly used by tourists, the technology has seen somewhat of a resurgence. Amidst a number of funicular systems, a true new cable car system can be found in the form of e.g. the MiniMetro system which fills the automated people mover niche.

Thanks to [JRD] for the tip.

When we look at how everyone’s favorite flying dinosaurs get around, we can see that although they use their wings a lot too, their legs are at least as important. Even waddling or hopping about somewhat ungainly on legs is more energy efficient than short flights, and taking off from the ground is helped by jumping into the air with a powerful leap from one’s legs. Based on this reasoning, a team of researchers set out to give flying drones their own bird-inspired legs, with their findings published in Nature (preprint on ArXiv).

The prototype RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments) drone is capable of hopping, walking, jumping onto an obstacle and jumping for take-off. This allows the drone to get into the optimal position for take-off and store energy in its legs to give it a boost when it takes to the skies. As it turned out, having passive & flexible toes here was essential for stability when waddling around, while jumping tests showed that the RAVEN’s legs provided well over 90% of the required take-off speed.

During take-off experiments the drone was able to jump to an altitude of about 0.4 meters, which allows it to clear ground-based obstacles and makes any kind of ‘runway’ unnecessary. Much like with our avian dinosaur friends the laws of physics dictate that there are strong scaling limits, which is why a raven can use this technique, but a swan or similar still requires a bit of runway instead of jumping elegantly into the air for near-vertical take-off. For smaller flying drones this approach would however absolutely seem to have legs.

Fresh off a world record for the fastest quadcopter, [Luke Bell] decided to try his luck with something more own to earth, namely trying to tackle the world record for the fastest RC car, with the current record set at 360 km/h. Starting off with a first attempt in what will be a video series, the obvious approach seems to be to get some really powerful electric motors, a streamlined body and a disused runway to send said RC car hurtling along towards that golden medal. Of course, if it was that easy, others would have done it already.

With the quadcopter record of nearly 500 km/h which we covered previously, the challenge was in a way easier, as other than air resistance and accidental lithobraking there are no worries about ground texture, tire wear or boundary layer aerodynamics. In comparison, the RC car has to contend with all of these, with the runway’s rough tarmac surface being just one of the issues, along with making sure that the wheels would hold up to the required rotation speed. For the wheels you got options like foam, hard rubber, etc., all with their own advantages and disadvantages, mostly in terms of grip and reliability.

So far speeds of over 200 km/h are easy enough to do, with foam wheels being the preferred option. To push the RC car to 300 km/h and beyond, a lot more experimentation and trial runs will have to be performed. Pending are changes to the aerodynamic design with features also commonly seen in F1 race cars such as downforce spoilers, diffusers and other tricks which should prevent the RC car from (briefly) becoming an RC airplane.