2026-01-16 00:30:23
AC induction motors are everywhere, from ceiling fans to vehicles. They’re reliable, simple, and rugged — but there are some disadvantages. It’s difficult to control the speed without complex electronics, and precisely placing the shaft at a given angle is next to impossible. But the core of these common induction machines can be modified and rewired into brushless DC (BLDC) motors, provided you have a few tools on hand as [Austin] demonstrates.
To convert an AC induction motor to a brushless DC electric motor (BLDC), the stator needs to be completely rewired. It also needs a number of poles proportional to the number of phases of the BLDC controller, and in this case the 24-pole motor could accommodate the three phases. [Austin] removed the original stator windings and hand-wound his own in a 16-pole configuration. The rotor needs modification as well, so he turned the rotor on a lathe and then added a set of permanent magnets secured to the rotor with JB Weld. From there it just needs some hall effect sensors, a motor controller and power to get spinning.
At this point the motor could be used for anything a BLDC motor would be used. For this project, [Austin] is putting it on a bicycle. A 3D printed pulley mounts to the fixed gear on the rear wheel, and a motor controller, battery, and some tensioners are all that is left to get this bike under power. His tests show it comfortably drawing around 1.3 kW so you may want to limit this if you’re in Europe but other than that it works extremely well and reminds us of one of our favorite ebike conversions based on a washing machine motor instead of a drill press.
2026-01-15 23:00:11
Over the course of its nearly 30 years in orbit, the International Space Station has played host to more “firsts” than can possibly be counted. When you’re zipping around Earth at five miles per second, even the most mundane of events takes on a novel element. Arguably, that’s the point of a crewed orbital research complex in the first place — to study how humans can live and work in an environment that’s so unimaginably hostile that something as simple as eating lunch requires special equipment and training.
Today marks another unique milestone for the ISS program, albeit a bittersweet one. Just a few hours ago, NASA successfully completed the first medical evacuation from the Station, cutting the Crew-11 mission short by at least a month. By the time this article is released, the patient will be back on terra firma and having their condition assessed in California. This leaves just three crew members on the ISS until NASA’s Crew-12 mission can launch in early February, though it’s possible that mission’s timeline will be moved up.
To respect the privacy of the individual involved, NASA has been very careful not to identify which member of the multi-nation Crew-11 mission is ill. All of the communications from the space agency have used vague language when discussing the specifics of the situation, and unless something gets leaked to the press, there’s an excellent chance that we’ll never really know what happened on the Station. But we can at least piece some of the facts together.
On January 7th, Kimiya Yui of Japan was heard over the Station’s live audio feed requesting a private medical conference (PMC) with flight surgeons before the conversation switched over to a secure channel. At the time this was not considered particularly interesting, as PMCs are not uncommon and in the past have never involved anything serious. Life aboard the Station means documenting everything, so a PMC could be called to report a routine ailment that we wouldn’t give a second thought to here on Earth.
But when NASA later announced that the extravehicular activity (EVA) scheduled for the next day was being postponed due to a “medical concern”, the press started taking notice. Unlike what we see in the movies, conducting an EVA is a bit more complex than just opening a hatch. There are many hours of preparation, tests, and strenuous work before astronauts actually leave the confines of the Station, so the idea that a previously undetected medical issue could come to light during this process makes sense. That said, Kimiya Yui was not scheduled to take part in the EVA, which was part of a long-term project of upgrading the Station’s aging solar arrays. Adding to the mystery, a representative for Japan’s Aerospace Exploration Agency (JAXA) told Kyodo News that Yui “has no health issues.”
This has lead to speculation from armchair mission controllers that Yui could have requested to speak to the flight surgeons on behalf of one of the crew members that was preparing for the EVA — namely station commander Mike Fincke and flight engineer Zena Cardman — who may have been unable or unwilling to do so themselves.
Within 24 hours of postponing the EVA, NASA held a press conference and announced Crew-11 would be coming home ahead of schedule as teams “monitor a medical concern with a crew member”. The timing here is particularly noteworthy; the fact that such a monumental decision was made so quickly would seem to indicate the issue was serious, and yet the crew ultimately didn’t return to Earth for another week.
While the reusable rockets and spacecraft of SpaceX have made crew changes on the ISS faster and cheaper than they were during the Shuttle era, we’re still not at the point where NASA can simply hail a Dragon like they’re calling for an orbital taxi. Sending up a new vehicle to pickup the ailing astronaut, while not impossible, would have been expensive and disruptive as one of the Dragon capsules in rotation would have had to be pulled from whatever mission it was assigned to.
So unfortunately, bringing one crew member home means everyone who rode up to the Station with them needs to leave as well. Given that each astronaut has a full schedule of experiments and maintenance tasks they are to work on while in orbit, one of them being out of commission represents a considerable hit to the Station’s operations. Losing all four of them at once is a big deal.
Granted, not everything the astronauts were scheduled to do is that critical. Tasks range form literal grade-school science projects performed as public outreach to long-term medical evaluations — some of the unfinished work will be important enough to get reassigned to another astronaut, while some tasks will likely be dropped altogether.
But the EVA that Crew-11 didn’t complete represents a fairly serious issue. The astronauts were set to do preparatory work on the outside of the Station to support the installation of upgraded roll-out solar panels during an EVA scheduled for the incoming Crew-12 to complete later on this year. It’s currently unclear if Crew-12 received the necessary training to complete this work, but even if they have, mission planners will now have to fit an unforeseen extra EVA into what’s already a packed schedule.
Having to bring the entirety of Crew-11 back because of what would appear to be a non-life-threatening medical situation with one individual not only represents a considerable logistical and monetary loss to the overall ISS program in the immediate sense, but will trigger a domino effect that delays future work. It was a difficult decision to make, but what if it didn’t have to be that way?
In other timeline, the ISS would have featured a dedicated “lifeboat” known as the Crew Return Vehicle (CRV). A sick or injured crew member could use the CRV to return to Earth, leaving the spacecraft they arrived in available for the remaining crew members. Such a capability was always intended to be part of the ISS design, with initial conceptual work for the CRV dating back to the early 1990s, back when the project was still called Space Station Freedom. Indeed, the idea that the ISS has been in continuous service since 2000 without such a failsafe in place is remarkable.
Unfortunately, despite a number of proposals for a CRV, none ever made it past the prototype stage. In practice, it’s a considerable engineering challenge. A space lifeboat needs to be cheap, since if everything goes according to plan, you’ll never actually use the thing. But at the same time, it must be reliable enough that it could remain attached to the Station for years and still be ready to go at a moment’s notice.
In practice, it was much easier to simply make sure there are never more crew members on the Station than there are seats in returning spacecraft. It does mean that there’s no backup ride to Earth in the event that one of the visiting vehicles suffers some sort of failure, but as we saw during the troubled test flight of Boeing’s CST-100 in 2024, even this issue can be resolved by modifications to the crew rotation schedule.
Everything that happens aboard the International Space Station represents an opportunity to learn something new, and this is no different. When the dust settles, you can be sure NASA will commission a report to dives into every aspect of this event and tries to determine what the agency could have done better. While the ISS itself may not be around for much longer, the information can be applied to future commercial space stations or other long-duration missions.
Was ending the Crew-11 mission the right call? Will the loses and disruptions triggered by its early termination end up being substantial enough that NASA rethinks the CRV concept for future missions? There are many questions that will need answers before it’s all said and done, and we’re eager to see what lessons NASA takes away from today.
2026-01-15 20:00:45
Since the RP2040 microcontroller is available as a stand-alone component, it’s easy enough for third parties to churn out their own variations — or outright clones of — the Raspberry Pi Pico. Thus we end up with for example AliExpress sellers offering their own versions that can be significantly cheaper than the genuine article. The ones that [electronupdate] obtained for a test and decapping session cost just $2.25 a pop.
As can be seen in the top image, the board from AliExpress misses the Raspberry Pi logo on the silkscreen for obvious reasons, but otherwise appears to feature an identical component layout. The QSPI Flash IC is marked on the die as BY250156FS, identifying it as a Boya part.
Niggles about flash ROM quality aside, what’s perhaps most interesting about this teardown is what eagle-eyed commentators spotted on the die shot of the RP2040. Although on the MCU the laser markings identify the RP2040 as a B2 stepping, the die clearly identifies it as an ‘RP2 B0’ part, meaning B0 stepping. This can be problematic when you try to use the USB functionality due to hardware USB bugs in the B0 and B1 steppings.
As they say, caveat emptor.
2026-01-15 17:00:30
We’ve been aware of projects like Cosmopolitan that allow you to crank out a single executable that will run on different operating systems. [Kamila] noticed that the idea was sound, but that the executables were large and there were some limitations. So she produced a 13K file that will run under Windows, Linux, or even in a Web browser. The program itself is a simple snake game.
There seems to be little sharing between the three versions. Instead, each version is compressed and stitched together so that each platform sees what it wants to see. To accommodate Windows, the file has to start with a PE header. However, there is enough flexibility in the header that part of the stub forms a valid shell script that skips over the Windows code when running under Linux.
So, essentially, Windows skips the “garbage” in the header, which is the part that makes Linux skip the “garbage” in the front of the file.
That leaves the browser. Browsers will throw away everything before an <HTML> tag, so that’s the easy part.
Should you do this? Probably not. But if you needed to make this happen, this is a clear template for how to do it. If you want to go back to [Kamila’s] inspiration, we’ve covered Cosmopolitan and its APE format before.
2026-01-15 14:00:04
[Anthony Francis-Jones], like us, has a soft spot for the educational electronic kits from days gone by. In a recent video you can see below, he shows the insides of a Philips EE08 two-transistor radio kit. This is the same kit he built a few months ago (see the second video, below).
Electronics sure look different these days. No surface mount here or even printed circuit boards. The kit had paper cards to guide the construction since the kit could be made into different circuits.
The first few minutes of the video recap how AM modulation works. If you skip to about the ten-minute mark, you can see the classic instruction books for the EE08 and EE20 kits (download a copy in your favorite language), which were very educational.
There were several radios in the manual, but the one [Anthony] covers is the two-transistor version with a PNP transistor as a reflex receiver with a diode detector with a second transistor as an audio power amplifier.
We covered [Anthony’s] original build a few months ago, but we liked the deep dive into how it works. We miss kits like these. And P-Boxes, too.
2026-01-15 11:00:44
Writing good, performant code depends strongly on an understanding of the underlying hardware. This is especially the case in scenarios like those involving embarrassingly parallel processing, which at first glance ought to be a cakewalk. With multiple threads doing their own thing without having to nag the other threads about anything it seems highly doubtful that even a novice could screw this up. Yet as [Keifer] details in a recent video on so-called false sharing, this is actually very easy, for a variety of reasons.
With a multi-core and/or multi-processor system each core has its own local cache that contains a reflection of the current values in system RAM. If any core modifies its cached data, this automatically invalidates the other cache lines, resulting a cache miss for those cores and forcing a refresh from system RAM. This is the case even if the accessed data isn’t one that another core was going to use, with an obvious impact on performance. As cache lines are a contiguous block of data with a size and source alignment of 64 bytes on x86, it’s easy enough to get some kind of overlap here.
The worst case scenario as detailed and demonstrated using the Google Benchmark sample projects, involves a shared global data structure, with a recorded hundred times reduction in performance. Also noticeable is the impact on scaling performance, with the cache misses becoming more severe with more threads running.
A less obvious cause of performance loss here is due to memory alignment and how data fits in the cache lines. Making sure that your data is aligned in e.g. data structures can prevent more unwanted cache invalidation events. With most applications being multi-threaded these days, it’s a good thing to not only know how to diagnose false sharing issues, but also how to prevent them.
