2026-01-16 05:00:16
Here’s something fun from [Chad Kapper] over on HackMakeMod: Escape Room Lockbox with the Cheap Yellow Display.
You may have heard of the “cheap yellow display” (CYD), so-called due to the board’s typical color. It’s a dodgy cheapo board with, among other things, TFT display, touchscreen, and ESP32 built-in. You can learn more about the CYD over here: Getting Started with ESP32 Cheap Yellow Display Board – CYD (ESP32-2432S028R).
In this build eight AA batteries are used to deliver 12 volts to operate a solenoid controlling a latch and 5 volts for the microcontroller. The encasing is clear in order to entice players in an escape-room style sitting. The custom software is included down the bottom of the project page and it is also available from arduino.cc, if that’s your bag.
Of course we’ve done plenty of other ESP32 TFT projects before, such as Piko – Your ESP32 Powered Fitness Buddy and ESP32 Brings New Features To Classic Geiger Circuit.
2026-01-16 03:30:27
A common task in a laboratory setting is that of sampling, where a bit of e.g. liquid has to be sampled from a series of containers. Doing this by hand is possible, but tedious, ergo an autosampler can save a lot of time and tedium. Being not incredibly complex devices that have a lot in common with e.g. FDM 3D printers and CNC machines, it makes perfect sense to build one yourself, as [Markus Bindhammer] of Marb’s Lab on YouTube has done.
The specific design that [Markus] went for uses a sample carousel that can hold up to 30 bottles of 20 mL each. An ATmega-based board forms the brain of the machine, which can operate either independently or be controlled via I2C or serial. The axes and carousel are controlled by three stepper motors, each of which is driven by a TB6600 microstep driver.
Why this design is a time saver should be apparent, as you can load the carousel with bottles and have the autosampler handle the work over the course of however long the entire process takes instead of tying up a human. Initially the autosampler will be used for the synthesis of cadmium-selenium quantum dots, before it will be put to work for an HPLC/spectrometer project.
Although [Markus] intends this to be an open hardware and software project, it will take a bit longer to get all the files and documentation organized. Until then we will have to keep manually sampling, or use the video as the construction tutorial.
2026-01-16 02:00:49
When we first heard the term “random laser,” we did a double-take. After all, most ordinary sources of light are random. One defining characteristic of a traditional laser is that it emits coherent light. By coherent, in this context, that usually includes temporal coherence and spatial coherence. It is anything but random. It turns out, though, that random laser is a bit of a misnomer. The random part of the name refers to how the device generates the laser emission. It is true that random lasers may produce output that is not coherent over long time scales or between different emission points, but individually, the outputs are coherent. In other words, locally coherent, but not always globally so.
That is to say that a random laser might emit light from four different areas for a few brief moments. A particular emission will be coherent. But not all the areas may be coherent with respect to each other. The same thing happens over time. The output now may not be coherent with the output in a few seconds.
A conventional laser works by forming a mirrored cavity, including a mirror that is only partially reflective. Pumping energy into the gain medium — the gas, semiconductor, or whatever — produces more photons that further stimulate emission. Only cavity modes that satisfy the design resonance conditions and experience gain persist, allowing them to escape through the partially reflecting mirror.
The laser generates many photons, but the cavity and gain medium favor only a narrow set of modes. This results in a beam that is of a very narrow band of frequencies, and the photons are highly collimated. Sure, they can spread over a long distance, but they don’t spread out in all directions like an ordinary light source.
Random lasers also depend on gain, but they have no mirrors. Instead, the gain medium is within or contains some material that highly scatters photons. For example, rough crystals or nanoparticles may act as scattering media to form random lasers.
The scattering has photons bounce around at random. Some of the photons will follow long paths, and if the gain exceeds the losses along those paths, laser emission occurs. Incoherent random lasers that use powder (to scatter) or a dye (as gain medium) tend to have broadband output. However, coherent random lasers produce sharp spectral lines much like a conventional laser. They are, though, more difficult to design and control.
Random lasers are relatively new, but they are very simple to construct. Since the whole thing depends on randomness, defects are rarely fatal. The downside is that it is difficult to predict exactly what they will emit.
There are some practical use cases, including speckle-free illumination or creating light sources with specific fingerprints for identification.
Biological tissue often can provide scattering for random lasers. Researchers have used peacock feathers, for example. Attempts to make cells emit laser light are often motivated by their use as cellular tags or to monitor changes in the laser light to infer changes in the cell itself.
The video below isn’t clearly using a random laser, but it gives a good overview of why researchers want your cells to emit laser light.
You may be thinking: “Isn’t this just amplified spontaneous emission?” While random lasers can resemble amplified spontaneous emission (ASE), true random lasing exhibits a distinct turn-on threshold and, in some cases, well-defined spectral modes. ASE will exhibit a smooth increase in output as the pump energy increases. A random laser will look like ASE until you reach a threshold pump energy. Then a sharp rise will occur as the laser modes suddenly dominate.
We glossed over a lot about conventional lasers, population inversion, and related topics. If you want to know more, we can help.
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.
