Making A Treadmill Into A 3D Printer

May 31, 2025 by Lewin Day No comments

A treadmill-style bed can be a great addition to a 3D printer. It allows prints to be shifted out of the build volume as printing continues, greatly increasing the size and flexibility of what you can print. But [Ivan Miranda] and [Jón Schone] had a question. Instead of making a treadmill to suit a 3D printer, what if you just built a 3D printer on top of a full-size treadmill?

The duo sourced a piece of real gym equipment for this build. They then set about building a large-scale 3D printer on top of this platform. The linear rails were first mounted on to the treadmill’s frame, followed by a gantry for the print head itself and mounts for the necessary stepper motors. The printer also gained a custom extra-large extruder to ensure a satisfactory print speed that was suitable for the scale of the machine. From there, it was largely a case of fitting modules and running cables to complete the printer.

Soon enough, the machine was printing hot plastic on the treadmill surface, thereby greatly expanding the usable print volume. It’s a little tricky to wrap your head around at first, but when you see it in action, it’s easy to see the utility of a build like this, particularly at large scale. [Ivan] demonstrated this by printing a massive girder over two meters long.

We started seeing attempts at building a belt-equipped “infinite build volume” printer back in 2017, and it took awhile before the concept matured enough to be practical. Even today, they remain fairly uncommon.

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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!

DIY Solar Generator Inspired By James Webb Telescope

May 30, 2025 by Lewin Day 23 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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Another Doom Port To The Atari ST

May 29, 2025 by Lewin Day 6 Comments

Last week, we examined a Doom port for the venerable Atari ST. As is so often the way with this thing, one netted another, and [Steve] wrote in to inform us about a different version under the name DOOM8088ST.

The port is so named because it’s based on Doom8088, which was originally written for DOS machines running Intel 8088 or 286 CPUs. Both ports are the work of [FrenkelS], and aims to bring the Doom experience into the far more resource constrained environment of the Atari ST. There is only very limited sound, no saving, and it only supports Doom 1 Episode 1. Still, it’s quite recognizable as Doom!

Doom8088ST is tunable to various levels of performance, depending on what you’re running it on. Low mode (30 x 128) is suitable for stock Atari ST machines running at 8 MHz. It’s described as having “excellent” framerate and is very playable. If you’ve got an upgraded ST or Mega STe, you can try Medium (60 x 128), which has greatly improved visuals but is a lot heavier to run.

Files are on Github for those interested to run or tinker with the code. Don’t forget to check out the other port we featured last week, either, in the form of STDOOM. Video after the break.

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You Can Make Your Own Ribbon Mic With A Gum Wrapper

May 29, 2025 by Lewin Day 11 Comments

There are lots of different types of microphone, with the ribbon microphone being one of the rarer ones. Commercial versions are often prized for their tone and frequency response. You can make your own too, as [Something Physical] demonstrates using a packet of chewing gum.

Yes, the ribbon in this microphone was literally gained from Airwaves Extreme gum. It’s got nothing to do with freshness or the special mintiness quotient of the material, though; just that it’s a conductive foil and it makes the YouTube video more interesting to watch.

The gum wrapper is first soaked in hot water and then acetone, such that the paper backing can be removed. The foil is then corrugated with a tube press with some baking paper used for protection during this delicate process. The “motor” of the ribbon microphone is then produced out of plexiglass, copper tape, and a pair of powerful magnets. The ribbon is then stretched between the magnets and clamped in place, acting as the part of the microphone that will actually vibrate in response to sound. As it vibrates in the magnetic field, a current is generated in response to the sound. From there, it’s just a matter of hooking up a custom-wound transformer to the wires leading to the “motor” and it’s ready to test. It works off the bat, but there is some noise. Adding shielding over the transformer and a proper enclosure helps to make the microphone more fit for purpose.

If you’ve ever wanted to experiment with microphone construction, it’s hard to go past the joy of building a simple ribbon mic. You can experiment at will with different sizes and materials, too; you needn’t just limit yourself to different brands of gum!

We’ve featured some other great mic builds over the years, too. Video after the break.

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Researchers Are Slowly Finding Ways To Stem The Tide Of PFAS Contamination

May 29, 2025 by Lewin Day 64 Comments

If you’ve been following environmental news over the past couple of decades, you’ve probably heard about PFAS – those pesky “forever chemicals” that seem to turn up everywhere from drinking water to polar bear blood. They’re bad for us, and we know it, but they’ve been leeching into the environment for decades, often as a result of military or industrial activity. What’s worse is that these contaminants just don’t seem to break down—they stick around in the environment causing harm on an ongoing basis.

Now, researchers are finally cracking the code on how to deal with these notoriously stubborn molecules. It won’t be easy, but there’s finally some hope in the fight against the bad stuff that doesn’t just wash away.
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Supercon 2024: Using An Oscilloscope To Peek Below The Noise Floor

May 28, 2025 by Lewin Day 7 Comments

When you’re hunting for a signal with your oscilloscope, the stronger it is, the better. If it’s weak, you might struggle to tease it out from other interference, or even from the noise floor itself. You might wish that you were looking for something more obvious rather than the electromagnetic equivalent of a needle in a haystack.

Finding hidden signals below the noise floor may be a challenge, but it needn’t be an insurmountable one. James Rowley and Mark Omo came to the 2024 Hackaday Superconference to tell us how to achieve this with the magic of lock-in amplifiers.

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