LED Matrix Earrings Show Off SMD Skills

February 21, 2024 by Dan Maloney 12 Comments

We’ll be honest with you: we’re not sure if the use of “LED stud” in [mitxela]’s new project refers to the incomprehensibly tiny LED matrix earrings he made, or to himself for attempting the build. We’re leaning toward the latter, but both seem equally likely.

This build is sort of a mash-up of two recent [mitxela] projects — his LED industrial piercing, which contributes the concept of light-up jewelry in general as well as the power supply and enclosure, and his tiny volumetric persistence-of-vision display, which inspired the (greatly downsized) LED matrix. The matrix is the star of the show, coming in at only 9 mm in diameter and adorned with 0201 LEDs, 52 in total on a 1 mm pitch. Rather than incur the budget-busting expense of a high-density PCB with many layers and lots of blind vias, [mitexla] came up with a clever workaround: two separate boards, one for the LEDs and one for everything else. The boards were soldered together first and then populated with the LEDs (via a pick-and-place machine, mercifully) and the CH32V003 microcontroller before being wired to the power source and set in the stud.

Even though most of us will probably never attempt a build on this scale, there are still quite a few clever hacks on display here. Our favorite is the micro-soldering iron [mitxela] whipped up to repair one LED that went missing from the array. He simply wrapped a length of 21-gauge solid copper wire around his iron’s tip and shaped a tiny chisel point into it with a file. We’ll be keeping that one in mind for the future.

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Shuji Nakamura: The Man Who Gave Us The Blue LED Despite All Odds

February 14, 2024 by Maya Posch 68 Comments

With the invention of the first LED featuring a red color, it seemed only a matter of time before LEDs would appear with other colors. Indeed, soon green and other colors joined the LED revolution, but not blue. Although some dim prototypes existed, none of them were practical enough to be considered for commercialization. The subject of a recent [Veritasium] video, the core of the problem was that finding a material with the right bandgap and other desirable properties remained elusive. It was in this situation that at the tail end of the 1980s a young engineer at Nichia in Japan found himself pursuing a solution to this conundrum.

Although Nichia was struggling at the time due to the competition in the semiconductor market, its president was not afraid to take a gamble on a promise, which is why this young engineer – [Shuji Nakamura] – got permission to try his wits at the problem. This included a year long study trip to Florida to learn the ins and outs of a new technology called metalorganic chemical vapor deposition (MOCVD, also metalorganic vapor-phase epitaxy). Once back in Japan, he got access to a new MOCVD machine at Nichia, which he quickly got around to heavily modifying into the now well-known two-flow reactor version which improves the yield.

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Building Nanoleaf-Inspired Wall Panels That Look Great

January 28, 2024 by Lewin Day 12 Comments

Nanoleaf is well-known as being that company that makes those lovely glowing tiles that you can hang on your wall. The only thing is, they’re not cheap. So if you want a really cool layout, you have to spend a great amount of money. [Projects with Red] was inspired by the basic concept, though, and whipped up their own gem-shaped wall tiles along similar lines.

The devices can work as a big clock if you so desire.

The irregular hexagon shape of each gem has ten connection points to attach the segments together. Physical connections are made using the 3D printed housings of each segment, while connections are simply made with wires and connectors hanging out the back for flexibility.

Each segment features a black printed housing with a solid lid and a translucent acrylic sheet to act as a diffuser. An addressable LED strip is mounted to the lid for illumination, with Dupont connectors for hooking them up to power and data. An ESP32 is used to drive the addressable LED chain, running the WLED.me software for easy control of the lights and animations. The video below also explains how to configure the segments into a giant colorful 7-segment display.

It’s a neat way to build some LED wall art, with plenty of scope to reconfigure it to suit your own needs. We’ve seen some other fun LED tile projects before, too.
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Is This The World’s Smallest N-Scale Train Layout?

January 23, 2024 by Kristina Panos 7 Comments

There’s just something about miniature worlds — they’re just so relaxing to look at and ponder. Think you don’t have ample room for a model train layout at your place? You may not be thinking small enough. [Peter Waldraff] knows a thing or two about hiding train layouts inside of furniture (that’s one solution), but this time, he’s built a track in plain sight that’s meant to sit on the bookshelf. The whole thing is just 5.5″ x 12″.

This N-scale layout was three years in the making, mostly because [Peter] was waiting for just the right little powered chassis to come along. For the layout, [Peter] started by creating custom flexible track by removing pieces with a sharp knife. He glued down the track to pink foam and used nails to hold it in place while the glue dried. He also built a wood frame around the base to stabilize it and hold some of the electronic components, including a switch made from an old ballpoint pen.

Then it was time to start decorating the thing, beginning with a couple of buildings made from more pink foam that are both lit up with LEDs. Eventually, [Peter] added a bunch of details like streetlights, animals, and garbage cans that really make the layout pop. As far as the engine goes, [Peter] picked up a Tomytec TM-TR02 on eBay and built a trolley out of two broken cars. [Peter]’s build is something you just have to see for yourself — fortunately for you, the build and demo video is after the break.

Like we said, [Peter]’s usual territory is hiding train layouts in end tables and coffee tables and the like, so it’s nice to see what he can do given different constraints.

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LED Art Project Is Geometrically Beautiful

December 13, 2023 by Lewin Day 7 Comments

There is no shortage of companies on the Internet willing to sell you expensive glowing things to stick on your walls. Many hackers prefer to make their own however, and [Chris] is no exception. His LED wall art is neat, tidy, and stylish, all at once.

Wanting a geometric design, [Chris] decided to have his layout designed by a random number generator. He created his own tool that would generate a design using preset segment lengths arranged in a random fashion. Once he found a layout that worked for him, he designed a set of plastic adapters that would let him connect pre-cut lengths of aluminium channel together so he could assemble his design.

With the frame complete, he then laid the LED strips into the channels, after mapping out how he would connect the full circuit of addressable LED strips. He enlisted a Raspberry Pi Zero W as the brains of the operation, responsible for commanding the strips to light in the colors of his desire.

In a nice aesthetic touch, he sanded the whole frame and painted it a uniform grey color. This hid the joins between the 3D-printed parts and the aluminium channels, and gave it a more finished look. He also went to the trouble of graphing out the locations of the various LEDs in the frame, and used this data as the basis for animations that race between points on the frame. It’s somehow more compelling than the usual simple color fades and flashes of typical commercial products.

It’s a tidy build, and a level more artful than some of the off-the-shelf products out there. For his investment of time and money, [Chris] has netted an excellent piece of wall art in the process.

LED Tester Also Calculates Resistor For Target Voltage

December 2, 2023 by Donald Papp 12 Comments

[mircemk] built a slick-looking LED tester with a couple handy functions built in. Not only can one select a target current to put through an LED, but by providing a target voltage, the system will automatically calculate the necessary series resistor. If for example the LED is destined for 14 V, this device will not only show how the LED looks at the chosen current, but will calculate the required resistor to get the same results on a 14 V system.

The buttons on the left control the target current and the voltage of the destination system. Once an LED is connected it will light up and the display indicates the LED’s forward voltage, the LED current, and the calculated series resistor value to obtain the same result at the selected target voltage. It’s a handy way to empirically dial in LED brightness values without needing to actually set up any particular test environment.

On the inside there’s little more than a handful of passive components, an Arduino, an LCD display, and a few buttons. This kind of tool reminds us of the highly clever component testers that hit the hobbyist scene years ago, showing what kind of advanced tricks a modern microcontroller is capable of with the right programming. (Here’s a look at how those work, if you’re interested in some deeper details.)

[mircemk] demonstrates his tool in the video, embedded below. We particularly like the attention he paid to the enclosure, giving it a very functional layout. It goes to show that when designing something, it’s never too early to consider enclosure and UI layout.

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Build Your Own Nanoleaf-Like Hex Lights

November 24, 2023 by Lewin Day 11 Comments

Nanoleaf makes a variety of beautiful LED lighting products, with their hexagon tiles particularly popular with gamers and streamers alike. However, they do come at a significant cost, particularly if you want to put together a larger display. [Giovanni Aggiustatutto] decided to build his own version from scratch, with a nice wooden finish to boot.

The benefit of the wooden design is that the panels look nice both when they’re switched on, and when they’re switched off. [Giovanni] selected attractive okumè plywood for the build, which is affordable and has a lovely grain. The hexagons were then fitted on their back side with strips of WS2812B LEDs. The first hexagon is fitted with an ESP32 that runs the lights, with the other hexagons having their LEDs daisychained from there. 3D printed frames were then fitted to each hexagon to allow them to be connected together into a larger wall-hanging piece.

Ultimately, building your own wall lights lets you customize them to operate exactly as you want, and often lets you save a lot of money, too. We’ve featured other similar builds before, too. Video after the break.

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