2025-12-25 14:00:00
Printing metal as easily as it is to printed with thermoplastics has been a dream for a very long time, with options for hobbyists being very scarce. This is something which [Rotoforge] seeks to change, using little more than an old Ender 3 FDM printer and some ingenuity. Best of all is that the approach on which they have been working for the past year does not require high temperature, molten metals and no fussing about with powdered metal.
Rather than an extruder that melts a thermoplastic filament, their setup uses metal wire that is fed into a friction welding tool head, the details of which are covered in the video as well as on the GitHub project page. Unlike their previous setup which we reported on last year, this new setup is both safer and much riskier. While there’s no more molten metal, instead a very loud and very fast spinning disk is used to provide the friction required for friction welding, specifically friction and rolling-based additive manufacturing (FRAM) as in the cited 2021 paper by [Ruishan Xie] et al. in Materials Today Communications. By the same lead author there’s also a 2025 paper that explores more complex implementations of FRAM.
With this method the feed wire (e.g. aluminium) will experience plastic shear, causing it to become somewhat fluid and capable of adhering to other surfaces. This same method can be used for other materials, including plastics and glass. As can be seen in the video, FRAM certainly seems viable, though it is a veritable rabbit hole of complications since you’re dealing with a high-velocity engineering challenge.
Here’s where [Rotoforge] found that slitting saws are a good, off-the-shelf option as they have basically the same high-speed-but-safely requirements. This left the motor part, which has to keep the friction wheel going. After a lot of trial and mostly error, it was found that the motor in a Dremel tool provided the solution in the form of a universal AC motor. Unlike brush-less DC motors, these AC motors are far more simpler, cheaper and can keep up a constant speed much better, which is probably why they’re still used in power tools everywhere. Ergo some cheap Vevor flex-shaft grinders were bought and adapted for some FRAM purposes.
Initial experiments with Al1100 aluminium alloy showed very good layer adhesion, to the point that they were very similar to a solid bar of aluminium. Due to the layered nature of the prints, they perform better than solid Al1100 parts in some tests. Thus the next challenge was to try more advanced printing techniques than a single straight line, which posed the bigger challenge and is where the basic Ender 3-based prototype met its match.
Next a fourth axis will be added to hopefully resolve some of the issues encountered with the current prototype, along with a host of other improvements to make printing more reliable and versatile. Although it’s clearly still early days for FRAM, it is rather exciting that even in a hobby setting without massive monetary investment it’s already possible to do this much.
Of course, it should definitely be said that eye- and hearing protection are absolute requirements if you intend to do some FRAM printing yourself. The video gives some idea of how loud the process is, and high-speed discs and wheels together with metalworking always introduce the exciting possibility of high-velocity shrapnel.
2025-12-25 11:00:15
We seldom talk about 3D printing lenses because most techniques can’t possibly produce transparent parts of optical quality. However, you can 3D print something like a lens, as [Luke Edwin] demonstrates, and get all kinds of crazy pictures out of it.
[Luke’s] lens isn’t really a lens, per se. There’s no transparent optical medium being used to bend light, here. Instead, he’s printed a very fine grid in a cylindrical form factor, stuck it on a lens mount, and put that on the front of a camera.
The result is effectively a set of parallel tubes that guide light on to the camera’s image sensor. With the lack of any sort of focus mechanism, you can’t use this “lens” to photograph anything more than a few centimeters away. Get something up close, though, and you can take very simple, very grainy images that are reminiscent of classic pixel art. [Luke] demonstrates this in some fun ways, using it to take photographs of money, a plant, and his own eye. The images look almost like art assets straight out of a 16-bit game. He’s got the STL file up for sale if you want to print your own at home.
We’d love to see this concept explored further, maybe with some supporting optics for more versatile use. In the meantime, you might explore other ways of using 3D printers for photographic gain.
2025-12-25 08:00:00
Key to efficient hardware emulation is an efficient mapping to the underlying CPU’s opcodes. Here one is free to target opcodes that may or may not have been imagined for that particular use. For emulators like the RPCS3 PlayStation 3 emulator this has led to some interesting mappings, as detailed in a video by [Whatcookie].
It’s important to remember here that the Cell processor in the PlayStation 3 is a bit of an odd duck, using a single regular PowerPC core (PPE) along with multiple much more simple co-processors called synergistic processing elements (SPEs) all connected with a high-speed bus. A lot of the focus with Cell was on floating point vector – i.e. SIMD – processing, which is part of why for a while the PlayStation 3 was not going to have a dedicated GPU.
As a result, it makes perfect sense to do creative mapping between the Cell’s SIMD instructions and those of e.g. SSE and AVX, even if Intel removing AVX-512 for a while caused major headaches. Fortunately some of those reappeared in AVX2.
The video goes through a whole range of Cell-specific instructions, how they work, and what x86 SIMD instructions they were mapped to and why. The SUBD instruction for example is mapped to VPDPBUSD as well as VDBPSADBW in AVX-512, the latter of which mostly targets things like video encoding. In the end it’s the result that matters, even if it also shows why the Cell processor was so interesting for high-performance compute clusters back in the day.
2025-12-25 05:00:45
Disposable cameras are a fun way to get into classical photography. However, they can also be a valuable source of interesting parts that can be put to other uses. For example, as [Billt] demonstrates, their viewfinders can be repurposed into a rather interesting lens for more serious cameras.
[Billt] was lucky enough to score a grabbag of used disposable cameras from a local film lab, and tore them down for parts. He was particularly interested in the viewfinders, since Kodak equipped its disposable cameras with actual plastic lenses for this very purpose.
[Billt] wanted to see what these lenses would do when thrown on the front of a proper digital camera, and set about designing a mount for that purpose. The 3D printed part was designed to mount one of the viewfinder lens assemblies on the front of any Sony E-mount camera. In a rather nifty trick, [Billt] realized the lens assembly could be installed in the adapter by pausing mid-way through the 3D print to drop it in. The only unfortunate thing? The lenses didn’t really work, and all the camera could see was a haze of unfocused light.
With the aid of some cardboard experiments, [Billt] decided to make some changes. The front element of the viewfinder was dumped, with the rear element being used solo instead. This was fitted to the adapter on a simple slide mechanism so that focus could be reliably adjusted. With these changes, the lens came good, and provided some really interesting shots. It’s quite a cropped lens and it can achieve a very close focus distance, as little as 1 inch in testing. It’s quite sharp in the center of the image, while softly blurring out towards the edges—something that sounds very familiar if you’ve used one of these disposable cameras in the wild.
Sometimes it’s fun to grab a random piece of junk to see if you can turn it into something good. Video after the break.
2025-12-25 02:00:15
There are plenty of lovely e-readers out on the market that come with an nice big e-paper display. There aren’t nearly as many that come with two. [Martin den Hoed] developed the Diptyx e-reader with such a design in order to better replicate the paper books of old.
The build is based around the ESP32-S3, a powerful microcontroller which comes with the benefit of having WiFi connectivity baked in. It’s hooked up to a pair of 648×480 e-paper displays, which are installed in a fold-open housing to create the impression that one is reading a traditional book. The displays themselves are driven with custom look-up tables to allow for low-latency updates when turning pages. The firmware of the device is inspired by the epub reader from [Atomic14], and can handle different fonts and line spacing without issue. Power is from a pair of 1,500 mAh lithium-polymer cells, which should keep the device running for a good long time, and they can be charged over USB-C like any modern gadget.
You can follow along with the project on the official website, or check it out on Crowd Supply if you’re so inclined. The project is intended to be open source, with files to be released once the design is finalized for an initial production run.
We’ve seen some great DIY e-reader builds over the years, and we’re loving the development we’re seeing in the writer deck space, too. If you’re whipping up something fun in this vein, be sure to let us know on the tipsline!
2025-12-24 23:00:36
If you read about Hall effect sensors — the usual way to detect and measure magnetic fields these days — it sounds deceptively simple. There’s a metal plate with current flowing across it in one direction, and sensors at right angles to the current flow. Can it really be that simple? According to a recent article in Elektor, [Burkhard Kainka] says yes.
The circuit uses a dual op amp with very high gain, which is necessary because the Hall voltage with 1 A through a 35 micron copper layer (the thickness on 1 oz copper boards) is on the order of 1.5 microvolts per Tesla. Of course, when dealing with tiny voltages like that, noise can be a problem, and you’ll need to zero the amplifier circuit before each use.
The metal surface? A piece of blank PCB. Copper isn’t the best material for a Hall sensor, but it is readily available, and it does work. Of course, moving the magnet can cause changes, and the whole thing is temperature sensitive. You wouldn’t want to use this setup for a precision measurement. But for an experimental look at the Hall effect, it is a great project.
Today, these sensors usually come in a package. If you want to know more about the Hall effect, including who Edwin Hall was, we can help with that, too.
