2026-03-03 05:00:28
Considering that the Serial Peripheral Interface bus semi-standard has been around since the early 1980s, it’s perhaps not that shocking that the controllers of the Super Nintendo Entertainment System (SNES) would take at least some strong design hints for the used protocol. This does however raise the question of exactly how compatible a SNES controller is when connected to the SPI master peripheral of any random MCU. Recently [James Sharman] set out to answer this question decisively.
The impetus for answering this question came after [James] designed a separate SNES controller board for his homebrew computer system, which led to many comments on that video saying that he could just have hooked the controller up to the SPI board in said homebrew system.
Here the short answer is that the SNES controller protocol is very close to SPI Mode-1, with a similar arrangement of clock/data/chip select (latch) lines and clocking. If you think of the SNES controller as an SPI device with just a MISO line, you’re basically there already. The only niggle that popped up was that the ‘MISO’ line does not get pulled into a high-impedance state when the active-low latch connection is pulled high.
This was fixable by introducing a 74HC125 tri-state buffer IC, after which both the original SD card and twin SNES controllers could be used simultaneously.
2026-03-03 03:30:42
There are many chess robots, most of which require the human player to move the opposing pieces themselves, or have a built-in mechanism that can slide the opposing pieces around to their new location. Ideally, such a chess robot would move the pieces just like how a human would, of course. That’s pretty much the promise behind the Manya Cynus chess robot, which [Matt] over at the Techmoan YouTube channel bought from the Kickstarter campaign.
Advertising itself as a ‘Portable AI Chess Robot’, the Manya Cynus chess robot comes in the form of a case that unfolds into a chess board and also contains the robotic arm that contains the guts of the operation. Powered by the open source Stockfish chess engine, it can play games against a human opponent at a few difficulty levels without requiring any online connectivity or a companion app. It moves its own pieces by picking up the metal-cored chess pieces with its arm, while its front display tries to display basic emotions with animated eyes. A 3-MP downward-facing camera is located on the head section, along with a microphone.
As for how well it works, [Matt] isn’t the best chess player, but he had a fair bit of fun with the machine. His major complaints circle around how unfinished the firmware still feels, with e.g., invalid moves basically ignored with only a barely visible warning popping up on the screen. In general, he’d rather classify it as an interesting development kit for a chess robot, which is where the BLE 5.1-based interface and a purported Python-based development environment provided by Manya seem to come into focus.
From the site, it’s not clear where this documentation and software can be found, and the chess robot appears to be fully sold out on the Kickstarter page. In addition to this, a promised companion app seems to have gone AWOL, too.
With no clear support or even availability, it would seem that this is less of a crowdfunding scam and more of a confusing product which may or may not become available again, yet which could perhaps provide inspiration to some DIY projects, as the basic principle seems sound enough. Or, keep it simple and use a gantry.
2026-03-03 02:00:14
Many different types of printers have entered the market over the years. Most of us are intimately familiar with the common inkjet and laser, both of which can be found in homes and offices all over the world. Then there are those old dot matrix printers that were so noisy in use, thermal printers, and even solid ink printers that occupied a weird niche for a time.
However, very little attention is ever paid to the LED printer. They’re not actually that uncommon, and they work in a very familiar way. It’s just that because these printers are so similar to an existing technology, they largely escaped any real notability in the marketplace. Let’s explore the inner workings of the printer tech that the world forgot.
To understand the LED printer, it helps to first understand the laser printer, and before that, the photocopier. Indeed, it was the latter technology that spawned the xerographic process that underpins all three machines.
Xerography is a compound word, from the Greek words xeros (dry) and graphia (writing). It’s where the Xerox company earned its name, and the process is at the heart of the photocopier. In the modern form we’re all familiar with, a photocopier relies on the use of a cylindrical drum, coated in a photoconductive material. This drum can be given an electrostatic charge, which remains on the surface when in darkness, but is conducted away when exposed to light. In a photocopier, the drum is exposed to light from a scanning lamp passing over a document. Where the document has light sections, the charges on the drum are conducted away, and where there are dark sections, the charge remains. The drum is then exposed to tiny particles of toner, which are attracted to the charged areas on the drum. A corona wire is then used to generate an opposite charge to that of the toner, pulling it off the drum and onto a piece of paper to replicate the original document. It’s then merely a matter of heating the paper to fuse the toner in place by melting it, and then the completed document is fed out of the photocopier. It’s this final step that gives fresh photocopies their characteristic warm feel and mild plasticky smell.
It wasn’t long before the xerography process was applied beyond mere photocopies. Xerox engineer Gary Starkweather realized in 1969 that a scanning laser beam could be used to draw directly on to the drum in place of the scanning lamp of a photocopier. A few years later, this led to the development of a prototype which proved the concept, and by 1976, the first commercial laser printer was on the market.
These printers were prized for their high speed and initially used in data center roles, before smaller desktop-sized units reached the market in the 1980s. Laser printers vary in construction, but most use a single laser diode with a rotating mirror that scans the beam over the drum. The beam is modulated as the mirror scans and the drum rotates to only remove charges from the drum in light areas that are not to have toner deposited. For color printing, some laser printers implement multiple drums, one for each color of toner—cyan, magenta, yellow, and key (black)—with four scanning lasers required in turn. The paper is passed over each, picking up one layer of toner at a time before it’s fused into the paper to create the final image. Some printers have also added a “transfer belt” to ease registration issues in color printers, wherein the drums deliver each color of toner to a belt, and the belt then delivers the toner to the paper in one fell swoop.
Laser printers are capable, high-speed printing machines, but they are expensive and do have a lot of moving parts. Engineers at Oki eventually realized it was possible to replace the combined laser diode and spinning mirror assembly with something simpler and more solid-state. Thus was born the LED printer, first developed in 1981 and commercialized in 1986. Rather than scanning a laser beam across a cylindrical drum, the LED printer has a line array of tiny individual LEDs that remove charges from the drum instead. The printer otherwise works in pretty much exactly the same way—only the method of discharging the drum was changed.
LED printers are generally a bit cheaper to manufacture, and can sometimes print faster than comparable laser printers. In part, this is because the line array can flash a segment of the drum all at once versus a laser beam which must be scanned across it. Where laser printers routinely offer 1200 x 2400 DPI resolution, it took LED printers some time to reach the same heights, as fitting 1200 LEDs into a single inch is no mean feat. However, Oki was able to achieve this milestone by 1997, while some cheaper models sit at the 600 DPI level instead. Meanwhile, in 2024, Canon did produce a LED-type printer using OLED technology, which enabled resolutions up to 4800 x 2400 DPI. The higher light emitter density possible with OLED technology allowed this leap forward.
Notably, most color LED printers tend to use a transfer belt setup, in which each LED/drum unit delivers toner to the belt which is then deposited on the paper in one pass. This is why LED printers tend to have similar print speeds for color and black-an-white use. This was an advantage over older color laser printers that didn’t use transfer belts, but instead had a color page make four separate passes over a drum, slowing printing down significantly.
Canon leveraged OLED technology to produce an LED-type printer with far superior resolution to traditional designs.
Funnily enough, some LED printers fly under the radar and are sold as “laser printers” despite not containing a laser. This is because, to the end user, the technology is not particularly different—the printers still use a charged drum for printing and still use toner to make an image. LED printers never differentiated themselves enough to make a big splash with disinterested consumers and commercial buyers who just want well-printed documents at the end of the day. LED printers mostly just look like laser printers and work similarly enough that few ever noticed the difference. Often, an LED printer will show up on e-commerce sites with “laser” scattered around the marketing copy because many understand them to be essentially the same thing from a user perspective.
LED printers are unlikely to become a household name any time soon, even if you have one in your household—if only because their close association with laser printing technology means most people never noticed they existed in the first place. In any case, next time you’re sitting at a table at your friend’s wedding with a bunch of people you’ve never met before, you now have an incredibly tedious technical lecture you can deliver to impress everybody at dinner. Spread the word about LED printers, because they’ve failed to do it themselves!
2026-03-03 00:30:54
Liquid nitrogen isn’t exactly an everyday material, but it’s acquired conveniently enough to be used in extreme overclocking experiments, classroom demonstrations, chemistry and physics experiments, and a number of other niche applications. Liquid oxygen, by contrast, is dangerous enough that it’s only really used in rocket engines. Nevertheless, [Electron Impressions] made some of his own, and beyond the obvious pyrotechnic experimentation, demonstrated its unusual magnetic properties. Check out the video, below.
The oxygen in this case was produced by electrolysis through a proton-exchange membrane, which vented the hydrogen into the atmosphere and routed the oxygen into a Dewar flask mounted at the cold end of a Stirling cryo-cooler. The cooler had enough power to produce about 30 to 40 milliliters of liquid oxygen per hour, enough to build up an appreciable amount in short order. As expected, the pale blue liquid caused burning paper to disappear in a violent flame, and a piece of paper soaked in it almost exploded when ignited.
More interestingly, a piece of oxygen-soaked paper could also be picked up with a strong enough magnet. This is due to molecular oxygen’s paramagnetism, which is too weak to be significant in a gas made of quickly-moving molecules, but becomes noticeable in a liquid. When some liquid oxygen was poured onto a strong magnet, it stuck to the edges of the magnet, whereas liquid nitrogen just splashed away. Even as the liquid oxygen evaporated, it was possible to faintly see some of the cold vapours sticking close to the magnet. [Electron Impressions] tried to create a kind of coil gun by wrapping a coil around a test tube containing liquid oxygen, but it didn’t really work. Any effect was imperceptible among the disturbances caused by boiling oxygen and the physical jolt of the power supply connecting.
It’s not a process we’ve seen before, but the boiling point of liquid nitrogen is lower than the boiling point of oxygen, so if you have a convenient source of liquid nitrogen, it’s simple enough to make liquid oxygen.
2026-03-02 23:00:07
For many decades humankind has entertained the notion that we can maybe tweak the Earth’s atmosphere or biosphere in such a way that we can for example undo the harms of climate change, or otherwise affect the climate for our own benefit. This often involves spreading certain substances in parts of the atmosphere in order to reflect or retain thermal solar radiation or induce rain.
Yet despite how limited in scope these attempts at such intentional experiments have been so far – with most proposals dying somewhere before being implemented – we have already embarked on a potentially planet-wide atmospheric reconfiguration that could affect life on Earth for centuries to come. This accidental experiment comes in the form of rocket stages, discarded satellites, and other human-made space litter that burn up in the atmosphere at ever increasing rates.
Rather than burning up cleanly into harmless components, this actually introduces metals and other compounds into the upper parts of the atmosphere. What the long-term effects of this will be is still uncertain, but with the most dire scenarios involving significant climate change and ozone layer degradation, we ought to figure this one out sooner rather than later.
Although Earth’s atmosphere looks pretty peaceful if you’re gazing at it from a space station in LEO or from a commercial airliner at cruising altitude, it’s actually constantly being assaulted. Everything from radiation to meteoroids, as well as the occasional asteroid are constantly making an attempt at inflicting real harm. This ranges all the way up to another mass-extinction event, but a meteoroid will settle for at the very least flattening another forest or inconveniencing a home owner.
Fortunately the atmosphere provides another feature beyond allowing us to not suffocate: by providing strong friction, the resulting high temperatures and intense plasma formation tend to burn up any object that tries to enter it at high velocity.
A less extreme form of this comes in the form of aerobraking, which is what spacecraft use to reduce their velocity relative to the planet; by creating enough friction in the atmosphere to shed kinetic energy, yet not heating up the spacecraft’s exterior to the point where things begin to melt, is incredibly helpful if one wishes to avoid having to resort to Plan B, being the violence of lithobraking.
This incinerator feature of the atmosphere is also very useful when it comes to the question of where the trash goes, whether it’s literal trash from the International Space Station, or things like discarded rocket stages and fairings, all the way to satellites that have reached their end of life stage. Yet much like the medieval solutions to waste disposal, the theme here is very much an ‘out of sight, out of mind’ approach, which is understandable as long as the volume of waste is still relatively small.
When a human-made object disintegrates in the atmosphere, it’s reduced to its base compounds, after interaction with the super-heated plasma that forms around said object. With the commonly used aluminium, for example, this means the production of aluminium oxide.
By far the largest amount of mass that will be burning up in the atmosphere over the coming years is formed by LEO internet constellations such as Starlink, which have a cumulative mass of over 10,000 tons. In addition, the second stage of the Falcon 9 rockets that are currently used to launch Starlink v1 and v1.5 satellites into LEO also burns up in the atmosphere. Recently, such a Falcon 9 stage suffered a mishap that caused it to disintegrate over Europe, rather than the typical trajectory over remote parts of Earth’s oceans.
This provided the perfect natural experiment. Batteries onboard satellites contain lithium, and because it’s relatively scarce in the atmosphere, it makes a great marker for the effects of satellites burning up on re-entry.
In the article by Robin Wing et al., as published in Communications Earth & Environment, the upper atmosphere measurements by a resonance lidar in Germany allowed for a ten-fold increase in atomic lithium to be measured after the stage had disintegrated near Ireland at an altitude of 100 km. Air currents subsequently dispersed the atomic debris over the rest of Europe.
Most notable perhaps was that the plume of atomic lithium was being detected at the same altitude of 100 km, after advecting for 1,600 km, placing ablation and dispersal in the mesosphere and lower thermosphere (MLT). Normally this plume would be dispersed far away from instruments, making it a fortuitous event from a scientific perspective that it could be measured like this.
Lithium is just one tracer for the debris plume, but there are many other metals. Here also lies the issue with comparing purely the mass of asteroids and rocket stages burning up in the atmosphere versus meteoroids and asteroids doing the same. The latter aren’t usually composed of intricate collections of metal alloys, rare earths and composite materials, but generally more boring things that we’d generously call ‘rocks’ or ‘gravel’, with the occasional iron variant mixed in.
As noted by Robin Wing et al., this feature makes artificial sources relatively easy to distinguish from natural ones. Since within the next decades re-entering satellites are projected to match or exceed 40% of natural meteoroid influx, the question remains of what these substances hanging around in Earth’s atmosphere will do to it and consequently life in Earth’s biosphere.
Back in 1987 the Montreal Protocol was signed. This banned the use of chlorofluorocarbons (CFCs) after it was found that the large-scale release of CFCs into the atmosphere from refrigeration systems and other sources had resulted in a significant depletion of the ozone layer. This layer is found primarily in Earth’s stratosphere and is essential for blocking harmful ultraviolet radiation which would otherwise irradiate the surface, in particular UV-C.
Although it’s currently projected that the ozone will have completely regenerated by 2045, a worrying 2024 research letter by José P. Ferreira et al. from the American Geophysical Union (AGU) with accompanying press release suggests that the massive rise in satellites burning up in the atmosphere over the coming decades could add so much aluminium oxides to the atmosphere that it could revert this ozone layer regeneration process.
Using an atomic-scale molecular dynamics simulation they found that a typical 250 kg satellite upon its fiery demise in Earth’s atmosphere releases about 30 kg of aluminium oxide nanoparticles. These may remain in the atmosphere for decades, meanwhile acting as a catalyst for chlorine activation and thus ozone depletion.
With currently projected mass of mega-constellation satellites burning up in the atmosphere, we’d be looking over 360 tons of aluminium oxides per year being added. As a catalyst, these aluminium oxides would not be used up, but would keep depleting the ozone layer as fast as the input products (ClO or Cl) are added.
This is just one potential impact that we might see as we keep adding all of these foreign substances to the atmosphere. Fortunately there’s nothing that says that we cannot have all our satellites and still dodge these issues.
The central issue here is that we have always treated the atmosphere similarly to the way that early medieval cities treated the local waterways. In their case it only took a few cholera- and other assorted epidemics to realize that maybe it was best to not use the waterways both for waste and drinking water. Similarly, we are now at a point where we’re beginning to realize that tossing our waste into the atmosphere may not be such a good plan, albeit it largely for financial reasons.
For many decades, it’s been accepted that rockets and satellites are effectively disposable, single-use items. Even the infamous STS (‘Shuttle’) program didn’t really push it much past ‘intense refurbishing’. Only recently has it become fashionable to reuse rockets and capsules, with the SpaceX Falcon 9 rocket’s first stage currently being the world-leader when it comes to partial reuse. Unfortunately its second stage still is burned up, as we saw with the analysis by Robin Wing et al.
What can be done? Back in 2020 we covered Northrop Grumman’s Mission Extension Vehicle (MEV), which provides a way to latch onto an existing satellite and provide propulsion as well as other functionality when the target’s own resources have become exhausted. In 2021 MEV-2 docked with Intelsat 10-02 to push it back to a geosynchronous orbit, extending its life by five years.
This is an example of on-orbit satellite servicing, which can take many forms. At its most basic it will just drag a satellite to a specific orbit, but it can also entail actual servicing, refueling and repairs. This was actually one of the concepts behind the Shuttle, with the Hubble Telescope being serviced and upgraded during a number of missions.
Unfortunately with the STS program’s in-orbit repair feature remaining mostly a pleasant dream due to the high cost of such a mission, we may one day see satellites being refueled and repaired by robotic systems. Although fully reusable rockets seem to be just around the horizon with SpaceX Starship and kin leading the way, we can only hope that we can soon figure out a way to make it cheaper to just repair a satellite than to toss it and launch a new one.
2026-03-02 20:00:01
[Yeckel] recently put the finishing touches on an ambitious implementation of a simple D-STAR (Digital Smart Technologies for Amateur Radio) transceiver using some very accessible and affordable hardware. The project is D-StarBeacon, and [Yeckel] shows it working on a LilyGO TTGO T-Beam, an ESP32-based development board that includes a SX1278 radio module and GPS receiver. It even serves a web interface for easy configuration.
What is D-STAR? It’s a protocol used by radio operators for voice that also allows transmitting low-speed data, such as short text messages or GPS coordinates. While voice is out of scope for [Yeckel]’s project (more on that in a moment) it can do all the rest, including send images. That makes beacon-type functions possible on inexpensive hardware, instead of requiring a full-blown radio.
As mentioned, voice is a big part of D-STAR. While [Yeckel] was able to access the voice data, attempts to decode it were unsuccessful. A valiant effort, but we suppose voice decoding isn’t terribly relevant to beacon-type operations like transmitting APRS (Automatic Packet Reporting System).
So far as [Yeckel] is aware, D-StarBeacon is currently the only open-source implementation of a D-STAR radio available on the internet, which is pretty interesting. We’ve seen projects that touch indirectly on D-STAR, but nothing like this.
Watch it go through its paces in the video embedded below. Since the T-Beam is just a microcontroller development board, the user interface comes from an Android app on a mobile phone, which is why you see a phone in the video.
