Taking “Movies” Of Light In Flight

December 25, 2024 by Elliot Williams No comments

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. Continue reading “Taking “Movies” Of Light In Flight” →

A visual timer for toddlers that uses LEDs that go out.

Time Management For Toddlers

December 25, 2024 by Kristina Panos 2 Comments

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.
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Tweezers Probe Reviewed

December 25, 2024 by Al Williams 1 Comment

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.

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When It Comes To DOS, Don’t Forget DR-DOS.

December 25, 2024 by Jenny List 12 Comments

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.

Close up of a Dutch etymology dictionary showing Esperanto, and a candle

Esperanto: The Language That Hoped To Unite The World

December 25, 2024 by Heidi Ulrich 34 Comments

Christmas: a good time to broach a topic of hope. We’re talking Esperanto. This language that spurred the hope it one day could hack the barriers between people, eliminating war and miscommunication. The video below unpacks the history of this linguistic marvel. Esperanto was a constructed language dreamed up in 1887 by Ludwik Zamenhof, a Polish-Russian eye doctor with a knack for linguistics and great ideals. If you’re a little into linguistics yourself, you’ll sure know the name stems from the Latin esperi: to hope.

Inspired by the chaos of multilingual strife in his hometown, Zamenhof created Esperanto to unite humanity under a single, simple, easy-to-learn tongue. With just 16 grammar rules, modular word-building, and no pesky exceptions — looking at you, English — Esperanto was a linguistic hack ahead of its time.

But Esperanto wasn’t just a novelty—it almost became the lingua franca of diplomacy. In 1920, Iran proposed Esperanto as the official language of the League of Nations, but the French vetoed it, fearing their language’s global dominance was at risk. From there, Esperanto’s journey took a darker turn as both Nazi Germany and Stalinist Russia persecuted its speakers. Despite this, Esperanto persisted, surfacing in quirky corners of culture, from William Shatner’s Esperanto-only horror film Incubus to its inclusion on NASA’s Voyager Golden Record.

Fast-forward to the digital age: Esperanto is thriving on online learning platforms, where over a million learners explore its minimalist elegance. It appears at places in various editions of Grand Theft Auto. It has even inspired modern makers to create new constructed languages, like Loglan, Toki Pona, and even Klingon. Could Esperanto—or any reimagined language—rise again to unite us? For curious minds, watch the video here.

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Open Source Multimeter Raises The Bar For DIY Tools

December 25, 2024 by Tom Nardi 25 Comments

Whether you only dabble in electronics as a hobby or it’s your full-time job, there are few tools as indispensable as the multimeter. In fact, we’d be willing to bet nearly everyone reading this site owns at least one of them. But as common and mindbogglingly useful as they may be, they aren’t perfect. Even the high-end models will invariably have some annoyance that only reveals itself once you become intimately acquainted with it.

Most people would just live with those quirks, especially when dealing with a cheaper model. But not [John Duffy]. Deciding nothing but perfection would do, he took every favorite feature he’d ever run into while using other multimeters and combined them into his scratch-built HydraMeter. In the process, he managed to come up with a few new ideas that push this device into a league of its own.

Some of the features of the HydraMeter will look familiar. You might even have them on your own personal meter, such as the wireless removable display module. Other features you’ll wish your meter had, such as the removable cartridge on the front of the device that lets you rapidly swap out a burned fuse. On the other side of the spectrum, there are some esoteric features that might leave you scratching your head. The ability to tell exactly how the meter is configured at a glance thanks to its exclusive use of toggle switches has a certain hacker appeal, but it’s a tricky user interface for most folks.

While the overall design of the HydraMeter may be divisive, one thing we can all agree on is that getting the project to this state took incredible determination. Over the years we’ve only seen a handful of individuals attempt to develop their own multimeters, and even then, none of them approached this level of fit and finish. The fact that [John] has turned all that effort over to the community by releasing his design under the CERN license is truly admirable.

[John] brought the HydraMeter out to Pasadena back in November for Supercon, and it got quite a reaction. And if you don’t like the user interface, it’s not hard to imagine how you could change it. This project has unquestionably pushed the state of the art for open source multimeters forward, and we’re eager to see where it goes from here.

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Break Me Off A Piece Of That Open Source Serial Adapter

December 25, 2024 by Tom Nardi 9 Comments

We know, you’ve already got a USB to serial adapter. Probably several of them, in fact. But that doesn’t mean you couldn’t use one more — especially when it’s as as cleverly designed as this one from [Anders Nielsen].

The first thing you notice about this adapter, and the big departure from the ones that are likely littering your parts bin, is that it terminates in a full-size male DSUB9 connector. With the ability to be directly plugged into a RS-232 port, this adapter will certainly catch the eye of retrocomputer enthusiasts. With a clever arrangement of jumpers, you can even reconfigure the RX and TX lines to be straight-through or cross over as needed.

But if you’re working with something that doesn’t have a literal serial port, no worries. All of the lines coming from the CH340G chip are broken out to a header so you can connect it up to whatever device you’re working with via jumpers.

In fact, if you’re really sure you’ll never need that RS232 feature, the PCB is even designed in such a way that you can simply snap it off. Admittedly it might seem a little odd to get a device like this if you didn’t want that capability. But once broken off, it’s not like the components go to waste. [Anders] has designed the board in such a way that if you flip it over and install a right-angle header, you can use the RS232 segment on a breadboard.

But the list of features doesn’t stop there. There’s also a 3.3 V regulator on board that you can use to power external circuits, as well as breakouts for the data lines in the USB-C connector. In keeping with the theme of the device, that part of the PCB can also be snapped off if you want to use it elsewhere.

Most folks probably’ won’t need all the capabilities offered by this particular serial adapter, and that’s fine. We’re still happy that it’s out in the wild and available for the community to use and adapt as an open source project.

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