To Test A (Smart) LED

February 24, 2025 by Al Williams 14 Comments

Adding LEDs to a project used to be enough to make it cool. But these days, you need arrays of addressable multi-color LEDs, and that typically means WS2812B or something similar. The problem is that while it was pretty easy to test garden-variety LEDs, these devices can be a bit harder to troubleshoot. [Gokux] has the answer, as you can see in the video below.

Testing these was especially important to [Gokux] because they usually swipe the modules from other modules or LED strips. The little fixture sends the correct pulses to push the LED through several colors when you hold it down to the pads.

However, what if the LED is blinking but not totally right? How can you tell? Easy, there’s a reference LED that changes colors in sync with the device under test. So, if the LEDs match, you have a winner. If not… well, it’s time to desolder another donor LED.

This is one of those projects that you probably should have thought of, but also probably didn’t. While the tester here uses a Xiao microcontroller, any processor that can drive the LEDs would be easy to use. We’d be tempted to breadboard the tester, but you’d need a way to make contact with the LED. Maybe some foil tape would do the trick. Or pogo pins.

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Add A Little WOPR To Your Server Rack

February 19, 2025 by Tom Nardi 29 Comments

Like so many of us, [aforsberg] found themselves fascinated with the WOPR computer from WarGames — something about all those blinking LEDs must speak to nerds on some subconscious level. But rather than admire the light show from afar, they decided to recreate it at a scale suitable for a 1U server rack.

So what goes into this WOPR display? In this case, the recipe simply calls for three MAX7219 dot matrix LED modules and a Raspberry Pi Pico, although you could swap that out for your favorite microcontroller if you wish. You should probably stick with something that at least runs MicroPython though, or else you won’t be able to use the included Python code to mimic the light patterns seen in the film.

What we like most about this project is how simple and inexpensive it is to recreate. There’s no custom PCB, and all the parts are mass produced enough that the economies of scale have made them comically cheap. Even at Amazon prices, you’re looking at around $50 USD in parts, and quite a bit less if you’ve got the patience to order everything through AliExpress.

Critics will note that, in its current state, this display just shows gibberish (admittedly stylish gibberish, but still). But as we’ve seen with similar projects, that’s simply a matter of software.

Valentine’s Day…Hacks?

February 15, 2025 by Elliot Williams 7 Comments

How do you reconcile your love for hacking projects together with your love for that someone special? By making him or her a DIY masterpiece of blinking red LEDs, but in heart shape. Maybe with some custom animations, and in a nice frame with a capacitive touch sensor to turn it on or off.

Or at least, that’s what I did. The good news is that my girlfriend, now wife, understands that this sort of present comes from a place of love. And it probably didn’t hurt that I also picked up some flowers to frame it with, and cooked her favorite lunch later that afternoon.

But if I’m 100% frank with myself, I’d have to admit that this was about 50% “present” and 50% “project”. Of course it also helps that she gets me, and that she knows that I put a bunch of effort into making it look as good as it did, and maybe because of that she forgives the 50% project.

Valentine’s day projects are a high-wire balancing act. If any other project fails, you can just try again. But here, the deadline is firm. Cosmetics matter a lot more on Valentine’s day than the other 364 days of the year, too. And finally, you really have to know the gift-receiver, and be sure that you’re not falling deeper into the excuse-for-a-cool-project trap than I did. And don’t forget the flowers.

I pulled it off with this one, at least, but I do feel like it was close, even today. Have you ever made a Valentine’s hacking project? How’d it go?

(Note: Featured image isn’t my project: It’s a lot more colorful!)

Home Depot Lamp Gets A Rainbow Upgrade

February 14, 2025 by Lewin Day 14 Comments

Home Depot has at times sold a neat spiral lamp that relies on LEDs to supply its soothing white glow. When [Craig Lindley] saw some modified versions on YouTube he decided he had to build one himself. The result is a charming rainbow lamp that really lights up a room (pardon the pun).

[Craig] first set about stripping the lamp of its white LED strips, replacing them with addressable WS2812B LEDs. No more would the lamp just output white light—any color in the RGB gamut was now on the table.

A powerful 10 amp 5 volt power supply was then installed to provide the necessary juice. A Wemos D1 Mini was pressed into service as the controller, which was also hooked up to an HC-SR04 infrared motion sensor. This provided the capacity to trigger the lamp when it detects someone moving nearby.

Alternatively, the lamp was given a time-activated mode as well. Either way, when activated, the lamp displays a range of colorful patterns on its elegant spirals, all with the aid of the popular FastLED library.

The final result is impressive—it looks almost stock, except it’s far more colorful and interesting to look at than the original. It’s also amusingly hard to display in our usual image formats because it’s so tall and narrow. In any case, we’ve seen some great lamp builds before, too. If you’re working on your own charming illuminations, don’t hesitate to drop us a line!

Powerful Flashlight Gets Active Air Cooling

February 9, 2025 by Lewin Day 16 Comments

LEDs were once little more than weedy little indicators with low light output. Today, they’re absolute powerhouses, efficiently turning a flow of electrons into a searing beam of light. Despite their efficiency, they can still put out a fair whack of heat. Thus, if you’re building a powerful flashlight like [CrazyScience], you might wanna throw some active cooling on there just to keep things happy. Check out the video below.

The build will not be unfamiliar to any casual observer of the modern DIY flashlight scene. It uses a flatpack LED module of great brightness and a wad of 18650 lithium-ion cells to provide the juice to run it. The LED itself is mounted in a 3D-printed frame, which leaves its rear exposed, and a small PC fan is mounted for air cooling. It’s not the most optimized design, as airflow out of the fan is somewhat restricted by the 3D-printed housing, but it’s a lot better than simple passive cooling. It allows the torch to be more compact without requiring a huge heatsink to keep the LED at an acceptable temperature.

The final torch doesn’t have the most ergonomic form factor, but it does work. However, as a learning project for a new maker, it’s a start, and the learning value of building something functional can’t be understated. If your desire for flashlights swerves to the more powerful, we’ve covered those, too. Just be careful out there.

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Tensegrity construction with Adafruit led strands

The Jell-O Glow Tensegrity Toy You Didn’t Know You Needed

January 30, 2025 by Heidi Ulrich 3 Comments

If you’re looking to add a pop of glowing whimsy to your workspace, check out this vibrant jiggly desk toy by [thzinc], who couldn’t resist the allure of Adafruit’s NOODS LED strands. [thzinc]’s fascination with both glowing LEDs and levitating tensegrity designs led to an innovative attempt to defy gravity once again.

The construction’s genius is all about the balance of tension across the flexible LED strands, with three red ‘arms’ and a blue ‘hanger’ arm supporting the central hub. [thzinc]’s early designs faced print failures, but by cleverly reorienting print angles and refining channel designs, he achieved a modular, sturdy structure. Assembly involved careful soldering, tension adjustments, and even a bit of temporary tape magic to perfect the wobbling equilibrium.

But, the result is one to applaud. A delightful, wobbly desk toy with a kind of a Jell-O vibe that dances to your desk’s vibrations while glowing like a mini neon sign. We’ve covered tensegrity constructions in the past, so with a little digging through our archives you’ll be able to find some unique variations to build your own. Be sure to read [thzinc]’s build story before you start. Feel free to combine the best out there, and see what you can bring to the table!

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RGB LED Display Simply Solves The Ping-Pong Ball Problem

January 30, 2025 by Donald Papp 19 Comments

A few years ago [Brian McCafferty] created a nice big RGB LED panel in a poster frame that aimed to be easy to move, program, and display. We’d like to draw particular attention to one of his construction methods. On the software end of things there are multiple ways to get images onto a DIY RGB panel, but his assembly technique is worth keeping in mind.

The diameter of ping pong balls is a mismatch for the spacing of LEDs on a strip. The solution? A bit of force.

The technique we want to highlight is not the fact that he used table tennis balls as the diffusers, but rather the particular manner in which he used them. As diffusers, ping-pong balls are economical and they’re effective. But you know what else they are? An inconvenient size!

An LED strip with 30 LEDs per meter puts individual LEDs about 33 mm apart. A regulation ping-pong ball is 40 mm in diameter, making them just a wee bit too big to fit nicely. We’ve seen projects avoid this problem with modular frames that optimize spacing and layout. But [Brian]’s solution was simply to use force.

Observing that ping-pong balls don’t put up much of a fight and the size mismatch was relatively small, he just shoved those (slightly squashy) 40 mm globes into 33 mm spacing. It actually looks… perfectly fine!

We suspect that this method doesn’t scale indefinitely. Probably large displays like this 1200 pixel wall are not the right place to force a square peg into a round hole, but it sure seemed to hit the spot for his poster-sized display. Watch it in action in the video below, or see additional details on the project’s GitHub repository.

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