Tidy LED Matrix Displays GIFs On Demand

May 30, 2025 by Lewin Day 4 Comments

When it comes to LED matrixes, building one is just the first step. Then you have to decide what to display on it. [panjanek] came up with a relatively flexible answer to this question, building an RGB LED matrix that can display the GIFs of your choice.

The web interface accepts GIFs for display.

[panjanek] grabbed WS2812B addressable LEDs for this project, assembling them into a 32 x 32 matrix that fits perfectly inside an off-the-shelf Ikea picture frame. The matrix is hooked up to an ESP8266 microcontroller, which acts as the brains of the operation. The WiFi-enabled microcontroller hosts its own web interface, with which the project can be controlled. Upon opening the page, it’s possible to upload a GIF file that will be displayed as an animation on the matrix itself. It’s also possible to stream UDP packets of bitmap data to the device to send real-time animations over a network.

It’s a neat build, and one that answers any questions of what you might display on your LED matrix when you’re finished assembling it. Code is on Github if you fancy implementing the GIF features in your own work. We’ve featured some unexpected LED matrix builds of late, like this innovative device for the M.2 slot. Meanwhile, if you’re cooking up your own creative LED builds, don’t hesitate to let us know on the tipsline!

2025 Pet Hacks Contest: Keep The Prey At Bay With The Cat Valve

May 30, 2025 by Jenny List 11 Comments

Some cats are what you might call indoor cats, happy to stretch out in the lap of indoor luxury and never bother themselves with the inclement outdoors again. Others however are fully in touch with their Inner Cat, and venture forth frequently in search of whatever prey they can find.

[Rkramer] has a cat of this nature,sadly one with a propensity for returning with live prey. To avoid this problem a solution is called for, and it comes in the shape of the Cat Valve, an automated cat door which enforces a buffer zone in their cellar to prevent unwanted gifts.

It’s a simple enough idea, when an IR sensor connected to a Raspberry Pi 4 detects the cat heading out into the world through the exterior cat flap, the computer fires up a motor connected to a lead screw which closes the flap between buffer zone and house. The cat then has the safety of the buffer zone, but can’t bring the prey fully inside.

If you’re a cat lover you’ll forgive them anything, but we have to admit to being on [Rkramer]’s side with this one. A useful way to keep the prey at bay is something we could have used a few times in the past, too. This project is part of the 2025 Pet Hacks contest. Done something similar for your cat? Why not make it an entry!

Hackaday Podcast Episode 323: Impossible CRT Surgery, Fuel Cells, Stream Gages, And A Love Letter To Microcontrollers

May 30, 2025 by Dan Maloney 1 Comment

Elliot and Dan teamed up this week for the podcast, and after double-checking, nay, triple-checking that we were recording, got to the business of reviewing the week’s hacks. We kicked things off with a look at the news, including a potentially exciting Right to Repair law in Washington state and the sad demise of NASA’s ISS sighting website.

Our choice of hacks included a fond look at embedded systems and the classic fashion sense of Cornell’s Bruce Land, risky open CRT surgery, a very strange but very cool way to make music, and the ultimate backyard astronomer’s observatory. We talked about Stamp collecting for SMD prototyping, crushing aluminum with a boatload of current, a PC that heats your seat, and bringing HDMI to the Commodore 64.

We also took a look at flight tracking IRL, a Flipper-based POV, the ultimate internet toaster, and printing SVGs for fun and profit. Finally, we wrapped things up with a look at the tech behind real-time river flow tracking and a peek inside the surprisingly energetic world of fuel cells.

Download this entirely innocent-looking MP3.

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DIY Solar Generator Inspired By James Webb Telescope

May 30, 2025 by Lewin Day 36 Comments

If you look at this solar generator from [Concept Crafted Creations], you might think it’s somehow familiar. That’s because the design was visually inspired by the James Webb Space Telescope, or JWST. Ultimately, though, it’s purpose is quite different—it’s designed to use mirrors to collect and harness solar energy. It’s not quite there yet, but it’s an interesting exploration of an eye-catching solar thermal generator.

To get that JWST look, the build has 18 mirrors assembled on a 3D printed frame to approximate the shape of a larger parabolic reflector. The mirrors focus all the sunlight such that it winds up heating water passing through an aluminum plate. Each mirror was custom made using laser cut acrylic and mirror film. Each mirror’s position and angle can be adjusted delicately with screws and a nifty sprung setup, which is a whole lot simpler than the mechanism used on the real thing. The whole assembly is on a mount that allows it to track the movement of the sun to gain the most sunlight possible. There’s a giant laser-cut wooden gear on the bottom that allows rotation on a big Lazy Susan bearing, as well as a servo-driven tilting mechanism, with an Arduino using light dependent resistors to optimally aim the device.

It’s a cool-looking set up, but how does it compare with photovoltaics? Not so well. The mirror array was able to deliver around 1 kilowatt of heat into the water passing through the system, heating it to a temperature of approximately 44 C after half an hour. The water was warmed, but not to the point of boiling, and there’s no turbines or anything else hooked up to actually take that heat and turn it into electricity yet. Even if there were, it’s unlikely the system would reach the efficiency of a similarly-sized solar panel array. In any case, so far, the job is half done. As explained in the build video, it could benefit from some better mirrors and some structural improvements to help it survive the elements before it’s ready to make any real juice.

Ultimately, if you need solar power fast, your best bet is to buy a photovoltaic array. Still, solar thermal is a concept that has never quite died out.

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This Week In Security: CIA Star Wars, Git* Prompt Injection And More

May 30, 2025 by Jonathan Bennett 3 Comments

The CIA ran a series of web sites in the 2000s. Most of them were about news, finance, and other relatively boring topics, and they spanned 29 languages. And they all had a bit of a hidden feature: Those normal-looking websites had a secret login and hosted CIA cover communications with assets in foreign countries. A password typed in to a search field on each site would trigger a Java Applet or Flash application, allowing the spy to report back. This isn’t exactly breaking news, but what’s captured the Internet’s imagination this week is the report by [Ciro Santilli] about how to find those sites, and the fact that a Star Wars fansite was part of the network.

This particular CIA tool was intended for short-term use, and was apparently so effective, it was dragged way beyond it’s intended lifespan, right up to the point it was discovered and started getting people killed. And in retrospect, the tradecraft is abysmal. The sites were hosted on a small handful of IP blocks, with the individual domains hosted on sequential IP addresses. Once one foreign intelligence agency discovered one of these sites, the rest were fairly easily identified.
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3D Filament lizards show decomposable joints

Sustainable 3D Prints With Decomposable Filaments

May 30, 2025 by Heidi Ulrich 24 Comments

What if you could design your 3D print to fall apart on purpose? That’s the curious promise of a new paper from CHI 2025, which brings a serious hacker vibe to the sustainability problem of multi-material 3D printing. Titled Enabling Recycling of Multi-Material 3D Printed Objects through Computational Design and Disassembly by Dissolution, it proposes a technique that lets complex prints disassemble themselves via water-soluble seams. Just a bit of H₂O is needed, no drills or pliers.

At its core, this method builds dissolvable interfaces between materials like PLA and TPU using water-soluble PVA. Their algorithm auto-generates jointed seams (think shrink-wrap meets mushroom pegs) that don’t interfere with the part’s function. Once printed, the object behaves like any ordinary 3D creation. But at end-of-life, a water bath breaks it down into clean, separable materials, ready for recycling. That gives 90% material recovery, and over 50% reduction in carbon emissions.

This is the research – call it a very, very well documented hack – we need more of. It’s climate-conscious and machine-savvy. If you’re into computational fabrication or environmental tinkering, it’s worth your time. Hats off to [Wen, Bae, and Rivera] for turning what might otherwise be considered a failure into a feature.

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Today In Edinburgh: The Open Hardware Summit

May 30, 2025 by Elliot Williams 9 Comments

Just a quickie for anyone who is in the neighborhood, today the Open Source Hardware Association’s annual Open Hardware Summit conference starts in Edinburgh, Scotland. If you’re able to make it, it’s a microcosm of the open-source hardware world, and full of great talks and great hackers.

If you’re not in Scotland, they have a livestream on YouTube that you should check out, as well as a Discord server for discussions during the event. It’s going on right now!