Solar Supercapacitor Lamp Probably Won’t Get You Saved At Sea

January 29, 2026 by Lewin Day 6 Comments

Most solar lights are cheap garbage that exist just to put more microplastics into the environment as they degrade in short order. [Jeremy Cook] built his own solar light, however, and this one might just last a little longer.

Most solar lights rely on the cheapest nickel-cadmium or nickel-metal hydride cells that are available on the market. They don’t tend to have a lot of capacity and they wear out incredibly fast. [Jeremy] went a different route for his build, though, instead relying on a rather tasty supercapacitor to store energy. Unlike a rechargeable battery, that may only last a few thousand cycles, these supercaps are expected to perform over 500,000 charge/discharge cycles without failure. With such longevity, [Jeremy] suggests his build could last a full 1369.8 years, assuming it charged and discharged once a day. Whether the plastic transistor, LEDs, or diode could hold up over such a long period is another question entirely.

Electronically, the build is relatively simple. The solar panel collects light energy and turns it into electricity, charging the supercaps through a diode. The supercaps are only able to discharge through a transistor, which only turns on when the voltage output by the solar panel drops at night time, and the voltage on the base becomes lower than that on the emitter. When current flows through the transistor, it then lights the LED in turn and the device glows in the darkness. As a nice touch, the whole circuit is installed in a glass jug of syrup originally sourced from Costco. Files are on Github for those eager to explore further.

Given the light-in-a-bottle construction, [Jeremy] also playfully imagined that a lamp like this could theoretically be used as a safety device. If lost at sea, you could charge it using the sun and try and use it to signal for help. However, upon casually exploring the concept, he notes that a small solar-powered light will only raise the chance of a far-off ocean rescue from “extremely unlikely” to “still very unlikely.”

You can do all kinds of neat things with free energy from the sun, from mowing your lawn to processing waste products. Video after the break.

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Buildling A Light That Reacts To Radio Waves

January 29, 2026 by Lewin Day 7 Comments

When it comes to electromagnetic waves, humans can really only directly perceive a very small part of the overall spectrum, which we call “visible light.” [rootkid] recently built an art piece that has perception far outside this range, turning invisible waves into a visible light sculpture.

The core of the device is the HackRF One. It’s a software defined radio (SDR) which can tune signals over a wide range, from 10 MHz all the way up to 6 GHz. [rootkid] decided to use the HackRF to listen in on transmissions on the 2.4 GHz and 5 GHz bands. This frequency range was chosen as this is where a lot of devices in the home tend to communicate—whether over WiFi, Bluetooth, or various other short-range radio standards.

The SDR is hooked up to a Raspberry Pi Zero, which is responsible for parsing the radio data and using it to drive the light show. As for the lights themselves, they consist of 64 filament LEDs bent into U-shapes over a custom machined metal backing plate. They’re controlled over I2C with custom driver PCBs designed by [rootkid]. The result is something that looks like a prop from some high-budget Hollywood sci-fi. It looks even better when the radio waves are popping and the lights are in action.

It’s easy to forget about the rich soup of radio waves that we swim through every day.

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Fiber Optic Lamp Modified To Be Scarily Bright

January 21, 2026 by Lewin Day 21 Comments

[Brainiac75] is a fan of fiber optic lamps, except for one thing—they’re often remarkably dim. Thus, they set out to hack the technology to deliver terrifying amounts of light while still retaining their quirky charm.

Older fiber optic lamps use a dim filament lamp or halogen lamp to light them up. They also often feature a spinning color disk to vary the light patterns, which does have the side effect of absorbing some of the already-limited light output.

When it came to upgrading his own decades-old lamp, [Braniac75] decided to initially stick within the specs of the original halogen lamp. The fixture was rated for 12 volts at 5 watts, with a GU4/GZ4 compatible base, and white light was desired so the color wheel could still do its thing. Swapping out the original 5 W halogen for a 2.5 W LED unit brought a big upgrade in brightness, since the latter is roughly equivalent to a 20 W halogen in light output. Upgrading to a 4.2 W LED pushed things even further, greatly improving the look of the lamp.

The video also explores modding a modern fiber optic lamp, too. It was incredibly cheap, running off batteries and using a single color-changing LED to illuminate the fibers. [Braniac75] decided to try illuminating the plastic fibers with an RGB stage lighting laser rig—namely, the LaserCube Ultra 7.5 W from Wicked Lasers. With this kind of juice, the fiber lamp is eye-searingly bright, quite literally, and difficult to film. However, with the laser output dialed way down, the lamp looks amazing—with rich saturated colors dancing across the fiber bundle as the lasers do their thing.

If you’ve ever wanted to build a fiber lamp that doesn’t look like a cheap gimmick, now you know how. We’ve looked at weird applications for these lamps before, too.

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Building Beautiful LED Lanterns With Black LED Acrylic

December 27, 2025 by Lewin Day 8 Comments

[Geeksmithing] and [When Geeks Craft] recently came together for a glowing collaboration. They wanted to build ever more attractive lanterns for a local parade event. They recently discovered a fantastic material that can really improve the look of whatever project you might be building with LEDs.

The material is commonly referred to as “Black LED Acrylic” or similar. In this case, it was sourced from TAP Plastics, though you can source similar acrylic from other vendors, too. From first glance, it looks like any other piece of black acrylic plastic. However, shine an LED through it, and it will be beautifully diffused and smoothed out to wonderful visual effect. A simple test of a 3×3 array of LEDs behind a 3D-printed grid shows how good this can look. It almost entirely eliminates hot spots, and the result looks like a display built out of juicy glowing cubes. The duo used this material to produce giant pixel art lanterns for their local parade. We only get a glimpse at the final build, but it appears giant Pacman and Blinky totems are on the way.

If you’ve been struggling to find a good way to diffuse the light from LEDs, you might want to give this stuff a try. Alternatively, you might explore some other methods we’ve looked at before, and don’t discount ping pong balls, either.

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Print Your Next LED Bezel

December 27, 2025 by Donald Papp 6 Comments

LED bezels (also known as LED panel-mount holders) are great, so how about 3D printing the next ones you need? Sure, they’re inexpensive to purchase and not exactly uncommon. But we all know that when working on a project, one doesn’t always have everything one might need right at hand. At times like that, 3D printing is like a superpower.

Printing a part you find yourself short of can be a lifesaver.

[firstgizmo]’s design is made with 3D printing in mind, and most printers should be able to handle making them. Need something a little different? You’re in luck because the STEP files are provided (something we love to see), which means modifications are just a matter of opening them in your favorite CAD program.

There’s not even any need to export to an STL after making tweaks, because STEP support in slicer programs is now quite common, ever since PrusaSlicer opened that door a few years ago.

Not using 5 mm LEDs, and need some other size? No problem, [firstgizmo] also has 3 mm, 8 mm, and 10 mm versions so that it’s easy to mount those LEDs on a panel. Combined with a tool that turns SVG files into multi-color 3D models, one can even make some panels complete with color and lettering to go with those LEDs. That might be just what’s needed to bring that midnight project to the next level.

Building A Wall-Mounted Sound Visualizer

December 27, 2025 by Lewin Day 7 Comments

Visualizers used to be very much in vogue, something you’d gasp in at amazement when you’d fire up Winamp or Windows Media Player. They’re largely absent from our modern lives, but [Arnov Sharma] is bringing them back. After all, who doesn’t want a cool visualizer hanging on the wall in their living room?

The build is based around the Raspberry Pi Pico 2. It’s paired with a small microphone hooked up to a MAX9814 chip, which amplifies the signal and offers automatic gain control to boot. This is a particularly useful feature, which allows the microphone to pick up very soft and very loud sounds without the output clipping. The Pi Pico 2 picks up the signals from the mic, and then displays the waveforms on a 64 x 32 HUB75 RGB matrix. It’s a typical scope-type display, which allows one to visualize the sound waves quite easily. [Arnov] demonstrates this by playing tones on a guitar, and it’s easy to see the corresponding waveforms playing out on the LED screen.

It’s a fun project, and it’s wrapped up in a slick 3D printed housing. This turns the visualizer into a nice responsive piece of wall art that would suit any hacker’s decor. We’ve featured some other great visualizers before, too. Continue reading “Building A Wall-Mounted Sound Visualizer” →

Windmill Desk Lamp Is Beautifully Soothing

December 19, 2025 by Lewin Day 25 Comments

Typically, lamps provide a stationary source of light to illuminate a given area and help us see what we’re doing. However, they can also be a little more artistic and eye-catching, like this windmill lamp from [Huy Vector].

It’s somewhat of a charming desk toy, constructed out of copper wire soldered into the form of a traditional windmill. At its base, lives a simple motor speed controller, while up top, a brushed DC gearmotor is responsible for turning the blades. As you might imagine, it’s a little tricky to get power to flow to the LED filaments installed on those blades while they happen to be rotating. That’s where the build gets tricky, using the output shaft of the motor’s gear drive and a custom slip ring to pass power to the LEDs. That power comes courtesy of a pair of 16340 lithium-ion cells, which can be juiced up with the aid of a USB-C charger board.

It’s an elegant build, and rather charming to watch in motion to boot. We love a good lamp build here at Hackaday, particularly when they’re aesthetically beautiful.

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