Blinded By The Light: The Problem With LED Headlights

December 26, 2024 by 178 Comments

Having a good set of (working) headlights is a crucial feature of any motor vehicle, assuming you want to be able to see the road ahead of you when there’s a lack of sunshine. Headlights are also essential to be noticed by other cars and traffic participants, but if installed improperly they can end up blinding an opposing driver with potentially fatal results. This is a major worry with LED lamps that are increasingly being installed in cars, often replacing the old-style halogen bulbs that have a very different color spectrum and beam patterns, to the dismay of fellow road participants.

This headlight glare can also be simulated in driving simulators, as in a 2019 article by [B.C. Haycock] et al. where the effect is of course diminished because displays can only get so bright. Of note is that it’s not just LED lights themselves, but also taller vehicles and misaligned headlights, all of which makes it important that the angle of your car’s headlights is proper. You want to see the road in front of you, after all, not illuminate every house in the nearest settlement two klicks away.

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Tech In Plain Sight: Incandescent Bulbs

December 26, 2024 by 71 Comments

While they are dying out, you can still find incandescent bulbs. While these were once totally common, they’ve been largely replaced by LEDs and other lighting technology. However, you still see a number of them in special applications or older gear. If you are above a certain age, you might be surprised that youngsters may have never seen a standard incandescent lightbulb. Even so, the new bulbs are compatible with the old ones, so — mechanically, at least — the bulbs don’t look different on the outside.

You might have learned in school that Thomas Edison invented the light bulb, but the truth is much stranger (public domain)

It has been known for a long time that passing a current through a wire creates a glow. The problem is, the wire — the filament — would burn up quickly. The answer would be a combination of the right filament material and using an evacuated bulb to prevent the filament degrading. But it took over a century to get a commercially successful lightbulb.

We were all taught in school that Thomas Edison invented the light bulb, but the truth is much more complicated. You can go back to 1761 when Ebenezer Kinnersley first caused a wire to glow. Of course, wires would quickly burn up in the air. By the early 19th century, limelight was fairly common in theaters. Limelight — also known as the Drummond light — heated a piece of calcium oxide using a gas torch — not electric, but technically incandescence. Ships at sea and forts in the U.S. Civil War used limelights to illuminate targets and, supposedly, to blind enemy troops at night. Check out the video below to see what a limelight looks like.

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OpenWRT, But On An Unsupported Router

December 26, 2024 by 15 Comments

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.

Open Source Lemontron 3D Printer Is Ready To Build

December 26, 2024 by 19 Comments

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.

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Taking “Movies” Of Light In Flight

December 25, 2024 by 10 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 12 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 6 Comments

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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