Kritik sah

In the era before PCB shops would make almost any PCB imaginable, as well making many other manufacturing processes for prototypes available to hobbyists, there were several ways of making PCBs at home. Many of which involve harsh chemicals and were easy to mess up. Getting a single-layer PCB using the toner transfer method, for example, took a bit of practice (and a fume hood) to get right. [Bettina Neumryr] is working on a custom two-layer PCB, and has a new trick to get it to come out right despite the added complexity of the second layer. The method starts out as a standard single-layer board in effect. Toner is ironed onto a copper board, in this case using a laminator, which allows the board to go into an acid bath which washes away all of the un-tonered copper. But with the second layer exposed, this would wash away the other side of the board completely. [Bettina] is using a new method here to protect that layer during the first bath: covering it in ink from a magic marker. W...

Although we often think that we got certain aspects of aerodynamics pretty much licked at this point, details like the optimal shape of a propeller remains hotly debated, both in- and outside of academia. This also includes wilder designs like toroidal propellers that even after more than a hundred years are still mostly just being evaluated. Recently [Neuronautics] took a shot at figuring out whether toroidal propellers even make sense . In order to do this, first an efficiency baseline was established using a conventional and highly optimized propeller. After scanning it in to get its exact geometry and running it through a computational fluid dynamics (CFD) simulation, the software spat out a number of about 73%. This left figuring out an optimized shape for the toroidal propeller to pit against it. While you can absolutely brute-force the seventeen shape parameters being considered here and test them in CFD, this would take insanely long. The hack here is to use multiple referen...

We often see scientific breakthroughs in journals or other media that’s reported on as if it’s a revolutionary technology guaranteed to reshape human existence, only to never hear about it again. A more cynical reason for this phenomenon is a certain amount of clickbait or engagement farming, but the real culprit often tends to be the discovery of a process that can’t produce the new material or effect at a scale that makes sense for mass production. One of those are MXenes (“max-enes”), a two-dimensional material first produced over a decade ago, but new research into them has developed a much more efficient way of producing them . Before this discovery, these materials were produced in a convoluted process involving the MXene precursor materials, combining them with an etchant, washing them off, and then repeatedly spinning them in a centrifuge to separate out unwanted byproducts. As one can imagine, this doesn’t produce material in an industrial q...

The PICO-8 is what is known as a ‘fantasy console’– you can program it, and there are oodles of games, but it’s not actually the 8-bit console it pretends to be. It’s a virtual machine, one that can run on top of any modern OS. When [UncleStem] got into PICO-8, he decided that he liked the PICO-8’s portability, he wanted a different kind of portability– so he took the ‘fantasy’ out of ‘fantasy console’ with his GameBoy-esqe handheld build , the build/dev video of which is embedded below. At its core, it’s a Raspberry Pi Zero2W. That’s rather overkill for an 8-bit virtual machine, but it’s what he had on hand, and it makes for an easy build. The real hero of the build is the 720 by 720 pixel IPS display that matches the PICO-8’s square aspect ratio and takes up most of the real estate on the handheld. Even better, it has HDMI in and sound support, so with some buttons and a battery the hardware is...

It’s been more than a year since [Henrik Forstén] built the first iteration of his synthetic-aperture radar (SAR) imaging drone, and he’s certainly been productive in the meantime. Not only did he develop a much more powerful autofocus algorithm to clean up the radar images, but he also extended the software to create high-resolution interferometric images . The main limitation of the original radar system was the GPS, which only had a resolution of about one meter; the autofocus algorithm owed much of its improved clarity to an improved estimation of the drone’s position. A simpler, though more expensive, solution was to add an RTK-capable GPS receiver. RTK (Real-Time Kinematic) receivers use a fixed ground station to constantly transmit a correction signal, letting them reach a couple centimeters of accuracy. Since the drone doesn’t actually need to know its position in real time, it can also use PPK (Post-Processing Kinematic) positioning, which compares recorded GPS signals aft...

It isn’t quite hailing frequencies open, but researchers from Harvard claim they’ve picked up a radio signal directly from a nearby exoplanet . Before you get too excited, planets in our solar system also emit RF, so no one credible is claiming these are extraterrestrial reruns of their version of I Love Lucy , but it is the first time they’ve localized a radio signal to an exoplanet, in this case, Beta Pictoris B. Speaking of space, the asteroid formerly known as 1981 EC26 is now sporting a new moniker: (14331) Alyankovic. If you think that sounds like (Weird) Al Yankovic, you aren’t wrong. The Tucson Star reports that, thanks to the efforts of several planetary scientists who are also Weird Al fans, the International Astronomical Union made the name official . Apparently, another asteroid now bears a name in honor of Weird Al’s predecessor, Tom Lehrer. The postmarketOS — er — Nura logo. If you follow open mobile phone software, you probably...