Articles by Donald Papp

We don’t know much more than what we see with [Kounotori_DIY]’s battery loader design (video embedded below) but it just looks so cool we had to share. Watch it in action, it’ll explain itself.
Before 3D printers made it onto hobbyist workbenches, prototyping something like this would have been much more work.
[Kounotori_DIY] uses a small plastic linear guide as an interface for an 18650 battery holder and as you can see, it’s pretty slick. A little cylindrical container slides out of the assembly, allowing a spent cell to drop out. Loading a freshly charged cell consists of just popping a new one into the cylinder, then snapping it closed. The electrical connection is made by two springy metal tabs on either end that fit into guides in the cylindrical holder.
It’s just a prototype right now, and [Kounotori_DIY] admits that the assembly is still a bit big and there’s no solid retention — a good bump will pop the battery out — but we think this is onto something. We can’t help but imagine how swapping batteries in such style with a nice solid click would go very nicely on a cyberdeck build.
It’s not every day that someone tries to re-imagine a battery holder, let alone with such style. Any ideas how it could be improved? Have your own ideas about reimagining how batteries are handled? Let us know in the comments! […]

[Angus] of Maker’s Muse has a video with a roundup of different 3D-printable hinge designs, and he points out that a great thing about 3D printing objects is that adding printable features to them is essentially free.
These hinges have an indexing feature that allows them to lock into place, no additional parts needed.
A great example of this is his experimental print-in-place butt hinge with indexing feature, which is a hinge that can lock without adding any additional parts. The whole video is worth a watch, but he shows off the experimental design at the 7:47 mark. The hinge can swing normally but when positioned just right, the squared-off pin within slots into a tapered track, locking the part in place.
Inspired by a handheld shopping basket with a lockable handle, [Angus] worked out a design of his own and demonstrates it with a small GoPro tripod whose legs can fold and lock in place. He admits it’s a demonstration of the concept more than a genuinely useful tripod, but it does show what’s possible with some careful design. Being entirely 3D printed in a single piece and requiring no additional hardware is awfully nice.
3D printing is very well-suited to this sort of thing, and it’s worth playing to a printer’s strengths to do for pennies what one would otherwise need dollars to accomplish.
Want some tips on designing things in a way that take full advantage of what a 3D printer can achieve? Check out printing enclosures at an angle with minimal supports, leveraging the living hinge to print complex shapes flat (and fold them up for assembly), or even print a one-piece hinge that can actually withstand a serious load. All of those are full of tips, so keep them in mind the next time you design a part. […]

What’s life without a little mystery? There’s one less rolling around after historians finally identified a donated mystery machine that had been in storage for years.
Feeding dough through this machine may have been faster, but probably not safer.
The main pieces of the machine are about a century old and any staff who may have known more about the undocumented device were no longer around to ask. The historical society finally posted pictures and asked for any insights, which eventually led to solving the mystery.
The machine is in all likelihood a beaten biscuit maker, which was a type of dense baked good popular in the American south. Making them called for a long and labor-intensive process of pounding and working the dough, and the society says this machine was likely created by a fellow trying to help his aunt streamline her business, offloading the labor of working the dough to a machine.
The machine had no branding of any sort and lacked any identifying marks. Its purpose was doubtfully obvious at the time, but no records remained and quite possibly none existed in the first place. Sound familiar? Perhaps someday our own undocumented projects and prototypes will mystify people. It’s certainly happened in the case of mysterious Roman dodecahedrons, which remain a head-scratching mystery. […]

[ClownVamp]’s art project The Junk Machine is an interactive and eye-catching machine that, on demand, prints out an equally eye-catching and unique yet completely meaningless (one may even say corrupted) AI-generated advertisement for nothing in particular.
The machine is an artistic statement on how powerful software tools that have genuine promise and usefulness to creative types are finding their way into marketer’s hands, and resulting in a deluge of, well, junk. This machine simplifies and magnifies that in a physical way.
We can’t help but think that The Junk Machine is in a way highlighting Sturgeon’s Law (paraphrased as ‘ninety percent of everything is crud’) which happens to be particularly applicable to the current AI landscape. In short, the ease of use of these tools means that crud is also being effortlessly generated at an unprecedented scale, swamping any positive elements.
As for the hardware and software, we’re very interested in what’s inside. Unfortunately there’s no deep technical details, but the broad strokes are that The Junk Machine uses an embedded NVIDIA Jetson loaded up with Stable Diffusion’s SDXL Turbo, an open source AI image generator that can be installed and run locally. When and if a user mashes a large red button, the machine generates a piece of AI junk mail in real time without any need for a network connection of any kind, and prints it from an embedded printer.
Watch it in action in the video embedded below, just under the page break. There are a few more different photos on [ClownVamp]’s X account. […]

Tiling a space with a repeated pattern that has no gaps or overlaps (a structure known as a tessellation) is what led mathematician [Gábor Domokos] to ponder a question: how few corners can a shape have and still fully tile a space? In a 2D the answer is two, and a 3D space can be tiled in shapes that have no corners at all, called soft cells.
These shapes can be made in a few different ways, and some are shown here. While they may have sharp edges there are no corners, or points where two or more line segments meet. Shapes capable of tiling a 2D space need a minimum of two corners, but in 3D the rules are different.
A great example of a natural soft cell is found in the chambers of a nautilus shell, but this turned out to be far from obvious. A cross-section of a nautilus shell shows a cell structure with obvious corners, but it turns out that’s just an artifact of looking at a 2D slice. When viewed in full 3D — which the team could do thanks to a micro CT scan available online — there are no visible corners in the structure. Once they knew what to look for, it was clear that soft cells are present in a variety of natural forms in our world.
[Domokos] not only seeks a better mathematical understanding of these shapes that seem common in our natural world but also wonders how they might relate to aperiodicity, or the ability of a shape to tile a space without making a repeating pattern. Penrose Tiles are probably the most common example. […]

If you wonder how Large Language Models (LLMs) work and aren’t afraid of getting a bit technical, don’t miss [Brendan Bycroft]’s LLM Visualization. It is an interactively-animated step-by-step walk-through of a GPT large language model complete with animated and interactive 3D block diagram of everything going on under the hood. Check it out!
nano-gpt has only around 85,000 parameters, but the operating principles are all the same as for larger models.
The demonstration walks through a simple task and shows every step. The task is this: using the nano-gpt model, take a sequence of six letters and put them into alphabetical order.
A GPT model is a highly complex prediction engine, so the whole process begins with tokenizing the input (breaking up words and assigning numerical values to the chunks) and ends with choosing an appropriate output from a list of probabilities. There are of course many more steps in between, and different ways to adjust the model’s behavior. All of these are made quite clear by [Brendan]’s process breakdown.
We’ve previously covered how LLMs work, explained without math which eschews gritty technical details in favor of focusing on functionality, but it’s also nice to see an approach like this one, which embraces the technical elements of exactly what is going on.
We’ve also seen a much higher-level peek at how a modern AI model like Anthropic’s Claude works when it processes requests, extracting human-understandable concepts that illustrate what’s going on under the hood. […]

[CentyLab]’s PocketPD isn’t just adorably tiny — it also boasts some pretty useful features. It offers a lightweight way to get a precisely adjustable output of 0 to 20 V at up to 5 A with banana jack output, integrating a rotary encoder and OLED display for ease of use.
PocketPD leverages USB-C Power Delivery (PD), a technology with capabilities our own [Arya Voronova] has summarized nicely. In particular, PocketPD makes use of the Programmable Power Supply (PPS) functionality to precisely set and control voltage and current. Doing this does require a compatible USB-C charger or power bank, but that’s not too big of an ask these days.
Even if an attached charger doesn’t support PPS, PocketPD can still be useful. The device interrogates the attached charger on every bootup, and displays available options. By default PocketPD selects the first available 5 V output mode with chargers that don’t support PPS.
The latest hardware version is still in development and the GitHub repository has all the firmware, which is aimed at making it easy to modify or customize. Interested in some hardware? There’s a pre-launch crowdfunding campaign you can watch. […]

We’re all pretty familiar with AI’s ability to create realistic-looking images of people that don’t exist, but here’s an unusual implementation of using that technology for a different purpose: masking people’s identity without altering the substance of the image itself. The result is the photo’s content and “purpose” (for lack of a better term) of the image remains unchanged, while at the same time becoming impossible to identify the actual person in it. This invites some interesting privacy-related applications.
Originals on left, anonymized versions on the right. The substance of the images has not changed.
The paper for Face Anonymization Made Simple has all the details, but the method boils down to using diffusion models to take an input image, automatically pick out identity-related features, and alter them in a way that looks more or less natural. For this purpose, identity-related features essentially means key parts of a human face. Other elements of the photo (background, expression, pose, clothing) are left unchanged. As a concept it’s been explored before, but researchers show that this versatile method is both simpler and better-performing than others.
Diffusion models are the essence of AI image generators like Stable Diffusion. The fact that they can be run locally on personal hardware has opened the doors to all kinds of interesting experimentation, like this haunted mirror and other interactive experiments. Forget tweaking dull sliders like “brightness” and “contrast” for an image. How about altering the level of “moss”, “fire”, or “cookie” instead? […]

The James Webb Space Telescope’s array of eighteen hexagonal mirrors went through an intricate (and lengthy) alignment and calibration process before it could begin its mission — but the process is far from being a one-and-done. Keeping the telescope aligned and performing optimally requires constant work from its own team dedicated to the purpose.
Alignment of the optical elements in JWST are so fine, and the tool is so sensitive, that even small temperature variations have an effect on results. For about twenty minutes every other day, the monitoring program uses a set of lenses that intentionally de-focus images of stars by a known amount. These distortions contain measurable features that the team uses to build a profile of changes over time. Each of the mirror segments is also checked by being imaged selfie-style every three months.
This work and maintenance plan pays off. The team has made over 25 corrections since its mission began, and JWST’s optics continue to exceed specifications. The increased performance has direct payoffs in that better data can be gathered from faint celestial objects.
JWST was fantastically ambitious and is extremely successful, and as a science instrument it is jam-packed with amazing bits, not least of which are the actuators responsible for adjusting the mirrors. […]