Tiny POV Turns Right Round For Volumetric Fun

December 3, 2023 by Dan Maloney 13 Comments

Just when you think the POV thing has run out of gas, along comes [mitxela] to liven things up. In this, he’s taken the whole persistence of vision display concept and literally spun up something very cool: a tiny volumetric “electric candle” display.

As he relates the story, the idea came upon him on a night out at the pub, which somehow led to the idea of an electric candle. Something on the scale of a tea light would fit [mitxela]’s fascination with very small and very interesting circuits, so it was off to the races. Everything needed — motor, LIR2450 coin cell, RP2040, and the vertical matrix of LEDs — fits into the footprint of the motor, which was salvaged from a CD drive. To avoid the necessity of finding or building a tiny slip-ring, he instead fixed everything to the back of the motor and attached its shaft to a Delrin baseplate.

The 8×10 array of surface-mount LEDs stands atop the RP2040 with the help of some enameled magnet wire, itself a minor bit of circuit sculpture. There’s also a 3D-printed holder for a phototransistor and IR LED, which form a sensor to trigger the display; you can see [mitxela] using a finger to turn the display off and move it back and forth. It goes without saying that these things always look better in person than they do in stills or even on video, but we still think it looks fantastic. There’s also a deep dive into generating volumetric data in the write-up, as well as an unexpected foray into the fluid dynamics calculations needed to create a realistic flame effect for the candle.

All in all, this is a fantastic if somewhat fragile project. We love the idea of putting this in a glass enclosure to make it look a little like a Nixie tube, too.

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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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Add Some Blinkenlights To Your Supercon Badge

December 1, 2023 by Kristina Panos 14 Comments

We’re not sure what is more amazing here: the glow of the blinkenlights themselves, the tedium involved in creating it, or the fact that [makeTVee] soldered 280 microscopic WS2812 LEDs while at Supercon.

This hack began before the con when [makeTVee] designed the LED-diffusing frame in Fusion 360 and printed it in clear resin. Rather than solder the LEDs straight, the frame has 280 teeth that support each one at a 55° angle.

Not only does this look cool, it makes the bridging of DOUT to DIN much easier. That leaves GND and VCC to be painstakingly connected with 30 AWG wire. How, you might ask? With a little help from 3.5x magnifying glasses and the smallest soldering iron tip available, of course.

But that’s not all. Since 280 addressable LEDs need a lot of power, [makeTVee] also designed a holder for the LiPo battery pack that fits into the existing AA holders.

Want to see more awesome badge hacks? Check out the compendium.

LED Ring Brings The Bling

November 28, 2023 by Kristina Panos 10 Comments

We’ve seen our share of light-up jewelry over the years, but for some reason — probably power — it’s almost always earrings or necklaces. So when we saw [ROBO HUB]’s LED ring, we had to check it out. It involves a bit of behind-the-scenes action in the form of a battery holder that you palm, but the end effect is quite cool.

Essentially, this is a 3D printed ring with SMD LEDs painstakingly soldered together in parallel along a pair of thin copper wires. The ring itself is in two parts: a base, and a cover to diffuse and protect the LEDs. A pair of wires run out from the ring and connect to a printed coin cell holder.

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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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How The WS2812 Is Made

November 19, 2023 by Elliot Williams 28 Comments

[Scotty Allen] of Strange Parts is no stranger to Chinese factory tours, but this one is now our favorite. He visits the font of all WS2812s, World Semi, and takes a good look at the machines that make two million LEDs per day.

The big deal with the WS2812s, and all of the similar addressable LEDs that have followed them, is that they have a logic chip inside the LED that enables all the magic. And that means die-bonding bare-die ICs into each blinky. Watching all of the machines pick, place, glue, and melt bond wire is pretty awesome. Don’t miss the demo of the tape-and-frame. And would you believe that they test each smart LED before they kick it out the door? There’s a machine that clocks some data in and reads it back out the other side.

Do we take the addressable LED for granted today? Probably. But if you watch this video, maybe you’ll at least know what goes into making one, and the next time you’re blinking all over the place, you’ll spill a little for the epoxy-squirting machine. After all, the WS2812 is the LED that prompted us to ask, three years ago, if we could live without one.
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Fixing Astronomy In The Blink Of An Eye

November 19, 2023 by Al Williams 37 Comments

If you’ve ever set a telescope up in your backyard, you probably learned how quick any kind of lighting ruins your observation. In fact, a recent study found that every year, about 10% of the stars that were visible the previous year disappear in the mishmash of light scattering through the atmosphere. A company called StealthTransit has a solution: blink the lights in a controlled way. They have an animated video explaining the concept.

The technology, named DarkSkyProtector, assumes there is LED lighting and that the light’s owner (or manufacturer) will put a simple device in line that causes the LED to blink imperceptibly. As you might guess, the telescope — presumably some giant observatory uses a GPS receiver to synchronize and then images only when the LED lights all turn off. That presumes, of course, that you have a significant number of lights under control.

It is hard to imagine every city and home having astronomy-safe lighting. However, we can imagine a university installing a lighting system on its campus to protect night viewing. The system underwent a test in the Caucasus mountains using a 24-inch telescope and was apparently quite successful with a shutter rate of about 150 Hz. We weren’t clear if each LED control module has to have a GPS-disciplined time source, but it seems like you’d have to. However, the post talks about how the bulbs wouldn’t cost more to make than conventional ones, so maybe they don’t have anything fancy in them.

You can see satellites in the day with some tech tricks. Want to check out observatories? Hit the road. Or, get time on a telescope with Skynet University.