TechyMagThings

In the world of scientific publishing there are many reasons why a paper can be retracted, but generally there is an obvious and clearly communicated reason for doing so. Thus when [Yves Gingras] – a historian of physics – and [Mahdi Khelfaoui] – a colleague – noticed recently that two 1940s papers by [Max Planck] had been quite recently retracted, this resulted in an eyebrow-raising double-take, before naturally publishing their investigation’s findings on arXiv.

They first became aware of this courtesy of the site Retraction Watch and their list of ‘Retractions by Nobel Prize winners‘, which had the authors do a spit-take when they saw [Max Planck] listed. This page led them to a total of two database entries, as listed above. One is for a 1940 paper, the other for a 1942 paper, only five years before [Planck]’s death.

As for the provided reasons, both articles were struck with a generic ‘copyright violation’, which at the very least seems somewhat puzzling, and started both authors of this recent investigation on their journey. What they found was less of a nefarious plot and more of an accidental black hole that had formed when scientific journals began to digitize papers.

The original journal that [Planck]’s papers were published in was absorbed like so many into Springer Nature, where an automated system then tried to sort through all the papers, including the usual detecting of copyright issues. With these papers predating the era of convenient DOIs and the more standard forms of citing related works, said automated system appears to have become rather confused and hurt these papers in its confusion.

From the side of Springer Nature there has so far been no commentary on this, and as of writing the original papers are still listed as withdrawn. Although one can still read the original scanned papers via the Internet Archive, such as here the 1940 paper, it’s disturbing to see that automated systems have apparently been let loose on these veritable archives of scientific and academic history, heedless of the damage inflicted along the way.

Although after fifteen years these two retractions were finally noticed, the more harrowing question is probably just how many papers from potentially less well-known authors were quietly scuttled. If this can happen to [Planck]’s works, it would appear that nobody is safe, including legends like [Bohr], [Einstein] and so many others.

For as popular as the piano is in music studios, homes, and schools, it almost defies logic. Compared to a guitar, harmonica, or drum set, pianos are incredibly complex machines that can have somewhere on the order of 8,000 moving parts in a case that can easily weigh hundreds of pounds and which often responds quite poorly to seasonal changes in temperature and humidity. But for putting up with all of these downsides, musicians are rewarded with an instrument that uniquely responds to touch, style, and emotion. A big reason for that is that mechanical complexity, and [Super Valid Designs] is attempting to bring that design to a drum set.

Compared to the complex machinery that connects the movement of a piano’s key to its hammer striking a string, a kick drum pedal is much simpler. It can only bounce off of the drum or get “buried” where the beater remains pressed up against the drum after hitting it. [Super Valid Designs] wanted something with a bit more finesse and control, so he first 3D printed a mechanism that throws the beater towards the drum head and then disconnects it mechanically from the pedal, so that it rebounds even if the pedal stays depressed. The next steps were more difficult, which involved making sure the mechanism reset itself in a repeatable way, without making too much noise of its own. This involved trying out a few different ideas and printing a massive amount of subtly different linkages, but in the end he’s left with a machine that nearly replicates all of the parts of a piano’s escapement,

The end goal of this project wasn’t simply to reproduce piano mechanisms on a drum set, though. [Super Valid Designs] hopes to make a kick drum that’s much smaller than those found in traditional kits, and since smaller drums respond poorly when the beater remains on or near the drum after striking it, a mechanism like this will dramatically improve the performance of the smaller drum and help reduce the requirement for perfect technique. And, maybe in 50 years or so, these types of escapements will take over the drumming world just like the piano escapement took over keyboards after its invention in the 1700s. Some simpler piano actions have been built before, but the complexity seems to be a requirement for all of the tasks they need to do whether its for a piano or a drum.

Perhaps the hardest thing for amateur astronomers just starting out is finding the things you want to look at. Prolific maker [mircemk] has submitted a quick-and-easy star-hopper device that will help guide your binoculars with laser-like precision using things you likely already have on hand: a smartphone, a mounting plate, and a green laser pointer.

The smartphone is running AstroHopper, an astronomy app that uses GPS and inertial navigation to know exactly where your phone is pointing, and offer an image of the sky on the screen. There are many others of this ilk, and there’s no reason [mircemk]’s trick won’t work with your favorite. The trick is decidedly simple: the smartphone is mounted to a flat plate, in line with a green laser pointer. Careful placement aligns the axis of the phone and the laser, and the mounting plate is set up to fit a tripod.

Using it is simple: with a labelled view of the sky displayed on the screen, one lines up the phone/laser combo with the desired object, and activates the laser pointer. [micremk] has wired in an on-off switch for this purpose and a large external battery, rather than relying on the stock pushbutton. Since the axis of the laser pointer and the phone are aligned, a green line launches out into the heavens for you to follow with your binoculars. Once you locate that green dot, you can turn off the laser. Yes, the computer has helped you find the object, but your muscles are doing the slewing and that will make it much more likely you start to learn the sky yourself rather than relying on electronic magic.

This is probably the simplest hack we’ve yet seen in the Frikkin’ Lasers Challenge, and yet also one of the most practical. If you enjoy playing with radiation that’s spontaneously emitted, there’s still time to get your entry together — the contest runs until July 23, 2026.

If you were in the market for a games console in 1990, the chances are that the object of your desire was either a Super Nintendo with its 16-bit 6502 derivative, or the Sega Megadrive, sold as the Genesis in North America, with its Motorola 68000. Both machines featured impressive graphics and sound for their time, but they remain firmly in the 16-bit era. Which makes it a surprise to see LinuxMD. It’s Linux, for the Sega Megadrive, with the latest mainline kernel.

The Motorola 68000 series of chips was the first porting target for Linux, and is still maintained in 2026. This build runs from an SD card  in a modern Megadrive storage peripheral, and is reported to run on the original hardware. The lowly 68000 in the Sega doesn’t have a memory management unit required for the full Linux experience, so what’s really running here is a kernel compiled with the -nommu option. That in itself is a feat, on this architecture. On it you get smolutils, a cut down coreutils, and that seems to be it.

We like this project, for pushing both console and kernel to the limit, even though we see that maybe it’s not the most practical Linux machine. Meanwhile though, this isn’t the only UNIX-like OS for this console.

Image: Evan-Amos, Public domain.

Offloading acceleration and braking to an electric motor in a hybrid configuration allows the less efficient combustion engine run in a more narrow set of RPM and torque ranges. In some cases the motor is decoupled from the mechanical drivetrain entirely and used simply as a generator, where it can run at a single speed all the time. And this concept isn’t limited to passenger vehicles, either. [rctestflight] put this premise to the test using a small knockoff Honda motor as a generator for an electric boat.

This project builds on a previous version where he used a much smaller hobby motor to see if it could generate usable power, and that system powered a small autonomous boat as a proof-of-concept. Those motors aren’t really designed to be used in this sort of application though, so this build upgrades the internal combustion engine and pairs it with an electric skateboard motor that’s configured to run as a generator. The setup is capable of producing almost 800 watts for as long as the gasoline lasts, provided that the 3D printed parts all hold together and the other parts don’t vibrate off of the assembly.

Out on the lake at full throttle, the small generator can get the boat up to seven knots (13 kph) but at this speed [rctestflight] reports that the generator is “quite unpleasant” due to the noise and vibration. Instead, he ran it on a test bench at several RPM and torque points and documented the efficiency of the motor at each one, and then operated the boat mostly at the point he found it to be most efficient. For a hybrid drivetrain, that not only decreases noise and vibration, but also maintenance and fuel efficiency.

Although the energy density of fossil fuels is much better than batteries, a fuel-free long-distance option is still available if you’d rather equip your boat with solar panels instead.

Sometimes, it’s hard to stop picking up your phone every few minutes to check on notifications and scroll endlessly through the slop of the day. [PushpendraC2] has been working on a solution to this problem that would ideally discourage such behavior —  a nifty little smartphone stand!

The concept is straightforward enough—the smartphone stand uses a simple tactile button to determine if your smartphone is sitting on the little 3D printed shelf, or not. However, the smarts inside do a bit more than that, too. An ESP32-S3 is charged with monitoring whether the smartphone is sitting in place, and starts counting “focus time” while it’s there. If the phone is picked up, the OLED display on the shelf starts ticking down a 5-second timer to encourage you to put it back. If you don’t, the focus time is reset and you lose your streak.

It’s also possible to tap a touch sensor on the device which sets a reminder timer, prompting you to put your phone back after a set period of time, between 2 to 30 minutes. A buzzer will then start going off to prompt you to put the phone down. If you want to track the devices impact, you merely need to log in to the web server hosted by the ESP32, which shows your current focus session time, along with a heatmap of your daily productivity.

It’s a simple idea, but one that uses a few neat psychological hooks to encourage compliance and behavioral change. We’ve featured similar projects in this vein before, No surprise, as phone addiction is a problem experienced by many.

Reachy Mini is a limbless desktop robot from Hugging Face made for human interaction experiments, and to give you an idea of what it’s like is a guide on how to implement expressive, local conversational AI complete with head movements and antenna wiggles. It’s conversational in the sense that it aims to feel natural, with low-latency responses and the ability to interrupt, with everything running on local hardware if one so wishes.

The software stack is essentially VAD (voice activity detection) → STT (speech-to-text) → LLM (large language model) → TTS (text-to-speech) which allows users to tweak things to their liking, or independently swap or modify pieces as things evolve.

This also allows users to tailor the services to match whatever their hardware is capable of. For example, one could easily use a frontier AI model via remote API for the LLM while keeping everything else local.

The local models in the example configuration are effective and relatively modest (Qwen3-4B-Instruct for the LLM, and even smaller models for the rest) but it’s nice to have the option to offload parts to remote providers if necessary.

Reachy Mini looked very interesting when it was launched as a kit last year, and since then Hugging Face has built up an impressive software suite and infrastructure through which users can easily share their applications. If you’re curious, there’s a simulator for Reachy Mini which should give you an idea of what it can do.