2024-12-26 20:00:00
Everyone likes something cheap, and when that cheap thing is a router that’s supported by OpenWRT, it sounds like a win. [Hennung Paul] ordered a Wavlink WL-WN586X3 for the princely sum of 39 Euros, but was disappointed to find his device a rev. 2 board rather than the rev.1 board supported by the Linux distribution. Toss it on the failed projects pile and move on? Not at all, he hacked together a working OpenWRT for the device.
It’s fair to say that a majority of Hackaday readers will have familiarity with Linux, but that’s something which runs on a sliding scale from “Uses Ubuntu a bit” all the way to “Is at one with the kernel”. We’d rate ourselves somewhere around halfway along that scale in terms of having an in-depth knowledge of userland and a working knowledge of some of the internals which make the operating system tick even if we’re apprehensive about tinkering at that level. [Henning] has no such limitations, and proceeds to take the manufacturer’s distribution, itself a heavily modified OpenWRT, and make it his own. Booting over tFTP we’re used to, and we’re particularly impressed to see him using a Raspberry Pi as a surrogate host for the desoldered Flash chip over SPI.
It’s a long path he takes to get the thing working and we’re not sure we could follow it all, but we hope that the result will be a new device added to OpenWRT’s already extensive support list. It’s sometimes a shock to find this distro is now over two decades old.
2024-12-26 17:00:18
In this era of cheap turn-key machines, the idea of actually building your own desktop 3D printer might seem odd to some. But if you’re looking for a challenge, and want to end up with a printer that legitimately sets itself apart from what they’re stocking on Amazon these days, then take a look at the Lemontron.
We’ve been keeping tabs on the development of this open source 3D printer for some time now, and just before Christmas, the files finally were released for anyone who wants to try putting one together themselves. There’s currently no formal kit available, but once you’ve printed out all the parts, there’s a very nice Bill of Materials you can find on the website which will tell you everything you need to complete the assembly — and critically — where you can get it.
The hotend and heated bed come from KB-3D, while the bulk of the rest of the components are sourced from AliExpress with a bit of DigiKey sprinkled in. There’s also a custom PCB you’ll want to pick up from your favorite board house. All told, building the Lemontron should cost you somewhat north of $400 USD. Of course, that assumes your time is free. But since you’re reading this on Hackaday, that probably a safe bet.
You can check out the video below for an expedited look at assembling the printer. It’s not a step-by-step guide exactly, but it should give you a good idea of what to expect before you commit to building the thing. It also provides a look at the design philosiphy behind the Lemontron, which largely eschews custom components and relies on off-the-shelf bits to tie all the printed parts together.
If you’re wondering were these upside-down 3D printers came from, the Lemontron is ultimately evolved from the Positron that we first covered back in 2021.
2024-12-26 14:00:00
This one isn’t clickbait, but it is cheating. [Brian Haidet], the guy behind Alpha Phoenix, has managed to assemble movie footage of a laser beam crossing his garage, using a rig he put together for just a few hundred dollars. How, you ask? Well, for the long version, you’re going to want to watch the video, also embedded below. But we’ll give you the short version here.
Light travels about a foot in a nanosecond. What have you got that measures signals on a nanosecond scale pretty reliably? Of course, it’s your oscilloscope. The rest of [Brian]’s setup includes a laser that can pull off nanosecond pulses, a sensor with a nanosecond-ish rise time, and optics that collect the light over a very small field of view.
He then scans the effective “pinhole” across his garage, emitting a laser pulse and recording the brightness over time on the oscilloscope for each position. Repeating this many thousands of times and putting them all together relative to the beginning of each laser pulse results in a composite movie with the brightness at each location resolved accurately enough to watch the light beam fly. Or to watch different time-slices of thousands of beams fly, but as long as they’re all the same, there’s no real difference.
Of course, this isn’t simple. The laser driver needs to push many amps to get a fast enough rise time, and the only sensor that’s fast enough to not smear the signal is a photomultiplier tube. But persistence pays off, and the results are pretty incredible for something that you could actually do in your garage.
Photomultiplier tubes are pretty damn cool, and can not only detect very short light events, but also very weak ones, down to a single photon. Indeed, they’re cool enough that if you get yourself a few hundred thousand of them and put them in a dark place, you’re on your way to a neutrino detector.
2024-12-26 11:00:00
It’s really never too early (or too late) to learn time management. All joking aside, carefully managing one’s time can result in some really wondrous achievements. So it’s best to learn early, when most of your time is spent generally having fun.
Let’s say you’ve just heard you have five minutes left to play, but what does that mean if you’re three years old? Not much, unless you have some visual cues to go by. That’s the idea behind [Julius Curt]’s visual timer for toddlers.
This lovely reverse progress bar uses a Wemos D1 mini to control a strip of six WS2812B LEDs at 30 LEDs/meter density. There’s a small OLED display for literate users, and the whole thing is childproof. [Julius] challenged himself to do this entire project in one day, and ended up finishing it in a little over eight hours total, including time to design the way cool knob. Be sure to check out the build video below.
If you struggle with managing your time, check out our own [Arya Voronova]’s personal account.
2024-12-26 08:00:44
Over the last few decades, electronic devices have drastically changed. Radios that once had point-to-point wiring gave way to printed circuit boards with through-hole parts, and now microscopic surface mount devices are the norm. But most of us still use probes that would have been just fine for a 1940s receiver. There are other options, of course. Among other things, you can now buy meters that have built-in tweezer probes. While not the first, the FNIRSI LCR-ST1 are affordable, and [TheHWcave] puts them to the test in the video below.
The tweezers come with two different pointy ends. It is more or less one of those testers that can identify and measure various components. Instead of the customary socket, this one has tweezer ends and, perhaps, a few extra functions.
The device can use several different voltages and frequencies while actively probing. Comparing some readings to a few other meters showed a bit of error, although nothing too drastic. The inductance reading of a very small inductor at 1 kHz was, however, too unstable to be useful.
The only downsides noted were that the probes could be a bit sharper for fine PCB work, and the display doesn’t rotate for left-handed operation. Both of those are probably fixable with a file and a firmware update. Overall, it looks like a reasonable low-cost tool.
Tools like this have been around for a while, but often at a higher cost. There are plenty of sophisticated test probes if you ever decide to look for them.
2024-12-26 05:00:00
Despite the latest and greatest Intel-derived computers having multi-core 64-bit processors and unimaginably fast peripherals, at heart they all still retain a compatibility that goes back to the original 8086. This means that they can, in theory at least, still run MS-DOS. The venerable Microsoft 16-bit OS may now be long discontinued, but there is still enough need for DOS that the open-source FreeDOS remains in active development. The Register are here to remind us that there’s another open-source DOS on the block, and that it has a surprising history.
SvarDOS is an open source DOS distribution, and it’s interesting because it uses a derivative of the DR-DOS kernel, an OS which traces its roots back to Digital Research’s CP/M operating system of the 1970s. This found its way briefly into the open source domain courtesy of the notorious Caldera Inc back in the 1990s, and has continued to receive some development effort ever since. As the Reg notes, it has something FreeDOS lacks, the ability to run Windows 3.1 should you ever feel the need. They take it for a spin in the linked article, should you be curious.
It’s something which has surprised us over the years, that aside from the world of retrocomputing we still occasionally find FreeDOS being distributed, usually alongside some kind of hardware maintenance software. Even four decades or more later, it’s still of value to have the simplest of PC operating systems to hand.
It’s worth pointing out that there’s a third open-source DOS in the wild, as back in April Microsoft released MS-DOS version 4 source code. But as anyone who used it will tell you, that version was hardly the pick of the bunch.
Header: Ivan Radic, CC BY 2.0.
