2026-08-25 10:00:27
Hypoesthesia, more commonly referred to as numbness, is one of the more distressing ailments that can affect us humans, primarily because it reminds us of just how much we rely on our sensation of touch in daily life. From experiencing the world around us, handling objects, noticing when you just bumped into that side table again and the comforting hug of a fellow human being, touch is perhaps the most important of our senses.
In that regard the recently published research by [Haofeng Chen] et al. on giving robots a skin that can experience touch seems rather important as it would give especially humanoid robots a more natural way to interact with their environment, using feedback from touch.
One of the essential parts of biological skin is that it is teeming with sensors, at a density level that provides excellent resolution as required, down to sensing e.g. small surface imperfections with one’s finger tips. Replicating this with an artificial skin for robotics has always been a problem, due to the wiring and/or reliability nightmare this poses with typical approaches. Instead of focusing on many individual sensors, [Chen] et al. focused on effectively creating the equivalent of a resistive touch screen in skin format.
The basic principle underlying the demonstrated artificial skin is electrical impedance tomography (EIT), which uses surface electrodes to form a tomographic image based on measures electrical resistivity. Core here is the flexible TPU layer with electrodes and the conductive fabric patches attached to the top TPU cover layer. The electrodes continuously measure the resistivity, with disturbances from those patches due to touch events on the cover layer altering these values. From this EIT can be used to reconstruct the location and strength of the touch event.
The results from the created prototypes were promising, with only 16 electrodes sufficing to create a fairly accurate pressure map. Hardware-wise this makes it thus quite uncomplicated, with the characterization of the TPU porosity and such along with the EIT algorithm (provided in the paper) probably being the biggest hurdles for hobbyist recreations.
2026-08-25 07:00:58
The AM29000 series of processors were AMD’s entry into the world of super-fast next-generation silicon of the late 1980s. It was a time when ARM was still a niche architecture in a British educational computer, the 68000 series was still a major player, and it was by no means certain that the x86 would maintain its position. It therefore wasn’t an unreasonable choice for someone building a high performance computer at the time, which is what [Oscar Toledo G.] and his father did. If that wasn’t enough, he went on to write an operating system for it in AM29000 assembly, complete with a GUI, a C compiler, and an up-to-date web browser for the late 1990s. The story makes for an engaging read.
It’s written across two parts, with the first looking at the computer and the early software development, and the second at the C compiler and web browser. It’s a tale of epic mastery of the machine, and something we remember ourselves, piecing together knowledge in a time before the Internet placed it all at our fingertips. Tales such as hand porting — we can’t really say compiling — C code into AM29000 machine code are completely next-level. You have to read these two write-ups, and there’s even an in-browser emulator should you want to try it.
Meanwhile, in case you think something is a little familiar here, he’s the same person who brought us a Transputer in the browser.
2026-08-25 04:00:15
It’s likely that even those of us who have never picked up a guitar in our lives will recognize the sound of an electric guitar with a fuzz box effects pedal. The raspy distorted sound has been at the heart of so many very well known recordings. Behind it is a distortion circuit, or as [Bill Jehle’s Mad Scientist Guitar Lab] is here to tell us, eight different circuit topologies.
The result is a fascinating trip through the evolution of rock music through the 1960s, as he examines circuits from simple diode clippers through to frequency doublers and phase shifters. He’s provided a playlist as an accompaniment so you can even have an immediate listen to each sound. It’ll mess up our YouTube recommendations, but worth it for the informative journey.
It’s also a window into a lost period in electronics where all they practically had was the transistor, so each device had to put in the maximum work for a living. Designing circuits like these called for intimate knowledge of the device characteristics, and just how they could be safely exceeded. The video is below the break, and well worth a watch.
If clever transistor music circuits interest you, you’ll love the flawed devices that gave the Roland 808 its sound.
2026-08-25 02:30:00
Many pieces of consumer electronics are build down to a price, and the corners cut show up in their performance. The Gameboy Advance from Nintendo is no exception: its audio is a PWM stream that sounds awful through the included amplifier. [Cajun Panda] has a fix though, in the form of a replacement audio chain.
It takes the form of a PCB that hooks into the pads of the removed GBA audio chip, and provides a much cleaner audio path with filtering and EQ and a class D audio amplifier. In addition there’s an audio codec and an ESP32 for Bluetooth connectivity, enabled by a long press of a GBA button and configured via a web interface on the ESP. Best of all there is no case modification, this is designed to remain as stock as possible.
Everything can be found in a GitHub repository should you wish to make your own, so if you want to bring your GBA audio up to scratch you know where to go. If you want to make it even better don’t forget, you can always upgrade the screen.
2026-08-25 01:00:04
If you’re blessed enough that you haven’t had blood drawn in a while, you might not have thought much about the process. You might imagine that a needle goes in, a syringe is drawn back, and the venous blood is thusly collected. Indeed, it can be done that way.
However, there is an altogether niftier and more efficient method of fast blood collection for pathology testing. It’s all about using vacuum and smart design to ease the work of phlebotomists, while maintaining a sterile and safe environment.
These days, if you get blood collected for testing, there’s a plenty good chance you’ll have it drawn into a vacutainer. It’s named as a portmanteau of “vacuum” and “container” because that’s fundamentally what the system relies upon. A vacutainer is a glass or plastic tube which holds a vacuum inside, sealed with a stopper. That vacuum can be used to help extract fluids to be stored inside the container—namely, blood, in most cases.
The method of use is relatively straightforward. A vacutainer needle is inserted into a patient’s vein to access the blood. The vacutainer needle does not have a typical syringe draw. Instead, the back end of the needle sits inside a plastic housing which accepts vacutainer tubes. There is a flexible rubber seal on the back end of the needle so blood doesn’t leak out when no tube is connected.
When a vacutainer tube is inserted into the housing, the vacutainer needle pierces the stopper of the tube. The vacuum inside then draws blood from the vein into the tube for collection. When full, the tube can be removed and it self-seals as the needle comes out of the stopper. Another tube can be quickly clipped into the vacutainer needle housing to draw further blood if more is needed, without leaks or mess causing contamination issues.
Vacutainer tubes are, by design, single use. They’re manufactured to capture a set quantity of blood for testing, based on the level of vacuum in the tube at the time it is sealed, and are disposed of after use. Labels are often included on the tubes allowing patient information to stay with the blood itself. Tubes have a shelf life, as with most medical paraphernalia, in particular since they may not maintain vacuum indefinitely.
The tubes are also typically filled with various additives in order to best preserve and prepare the blood while it awaits testing, and stoppers are color-coded to indicate this. The precise additives used are highly dependent on the testing required. A tube for a standard blood culture draw will typically be filled with sodium polyanethol sulfonate, which acts as an anti-coagulant, with growth media also present for microorganisms.
Coagulation tests will use tubes with sodium citrate inside, while a test for lead will often use a tube with sodium EDTA chelator inside. Some basic blood component tests will use a plain tube with no additives, while others are highly specific—tuberculosis testing often uses purpose-made tubes with antigen additives ready to go. Some tubes include special serum-separating agents which help with splitting blood into its component parts when shaken or centrifuged, useful for certain tests that look at different blood cell types individually.
If you’ve ever dared to watch while having your blood drawn in this manner, the technology can look quite swish. The tubes are easy to hotswap without leaking any blood and several tubes can be filled in under a minute once the phlebotomist has found an appropriate vein.
However, the technology is not particularly new. It was developed all the way back in 1947 by Joseph Kleiner, though other vacuum-based blood draw techniques existed previously. His goal in developing the technology was to ease patient discomfort and reduce the spillage of blood. This stemmed from his experience seeing his terminally-ill wife suffer multiple needle punctures whenever multiple blood tests were required, and seeing the mess caused when syringes were emptied into test tubes for processing and testing. His inspiration was seeing vacuum-sealed tubes used by the military to transport blood during World War II; the product he developed would later reach the market in 1949. They had the benefit of keeping the blood from exposure to air, reduced the number of punctures required along with the chance of needle stick injuries and infection, and ensured blood was collected in standard volumes and conditions, which aided clinical accuracy. Plastic versions were developed by medical supplier Becton Dickinson in the 1960s, and have become widely popular in the phlebotomy field since.
If you’re not in the medical field, and you’ve managed to avoid regular blood tests, you probably haven’t even noticed vacutainers. Alternatively, you might simply live in an area where their use is uncommon, or you’ve just been intently looking away while your blood has been drawn. In any case, they remain a neat little bit of technology that makes a messy, hazardous, medical process as clean and tidy as possible.
Featured image: “Drawing Test tubes different colors” by [Goldmund100].
2026-08-24 23:30:00
One of the fun aspects of open source software is that you can often find so many libraries and tools that implement the functionality you need, but ease of use for e.g. artists is often not a priority. This is where [Edin Spiegel] ‘s annoyances with photogrammetry tools led him down to the path of creating the Simple Photogrammetry GUI project, which is basically what it says on the tin.
In an associated video its development and use is demonstrated, combining tools like Colmap, OpenMVS, mvs-texturing, pymeshlab, brush and PoissonRecon to implement both photogrammetry and gaussian splatting to turn those photos into a not too shabby mesh along with realistic textures.
The GUI uses the Flutter GUI kit, so Linux support is still somewhat sketchy, but should work in this new release of this GUI wrapper. The author is asking for people to test this GUI and report any issues found so that they can be addressed.
From a quick glance at the project and the comments to the video it seems quite useful for anyone who wants to get started quickly with photogrammetry. One niggle is perhaps that it relies on processing using CUDA, with a much slower fallback to CPU processing if you do not happen to have an Nvidia-blessed GPU installed. Of course this is one of those universal issues in a world where theoretically everyone should be using OpenCL already.
In addition to the build instructions you can also download an AppImage for Linux and compiled binaries for Windows to theoretically get started as fast as your internet connection allows. Interestingly, the AppImage is well over a GB in size, whereas the Windows ZIP file is just 207 MB for the v1.1.5 release, so take that into account.
