Author: Dan Maloney

3283 Articles

Compact Cycloidal Drive Lives Inside This Custom Brushless Motor

February 16, 2024 by 7 Comments

With the popularity of robot dogs, many people have gotten on the bandwagon and tried building DIY versions. Most of them end up attaching a gearbox to an off-the-shelf brushless motor and call it a day. Not everyone goes that way, though, which is why this internal cycloidal drive actuator caught our eye.

Taking design cues from the MIT Mini Cheetah, [Aaed Musa] approached his actuator from the inside out, literally. His 3D printed cycloidal gearbox is designed to fit inside the stator of a BLDC motor. And not just any BLDC motor, but one built mostly from scratch using a hand-wound — and unwound, and wound again — stator along with a rotor that started as a printed part but was eventually machined from steel. Apart from its fixed ring, the cycloidal drive was mostly 3D printed, with everything fitting nicely inside the stator.

The video below shows the design and assembly process as well as testing of the finished drive. It seems to do really well with speed and positional accuracy, and it delivers a substantial amount of torque. Maybe a little too much, though; testing it with a heavy weight on the end of an arm got the stator coils hot enough to warp the printed parts within. But no matter; this was only a prototype after all. [Aaed] says improvements are in the works, including replacing all the plastic parts with metal ones.

Need a little background on cycloidal drives? They’re pretty cool.

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Retrotechtacular: Some Days You Just Can’t Get Rid Of A Nuclear Bomb

February 15, 2024 by 19 Comments

It may seem a bit obvious to say so, but when a munition of just about any kind is designed, little thought is typically given to how to dispose of it. After all, if you build something that’s supposed to blow up, that pretty much takes care of the disposal process, right?

But what if you design something that’s supposed to blow up only if things go really, really wrong? Like nuclear weapons, for instance? In that case, you’ll want to disassemble them with the utmost care. This 1993 film, produced by the US Department of Energy, gives a high-level overview of nuclear weapons decommissioning at the Pantex plant in Texas. Fair warning: this film was originally on a VHS tape, one that looks like it sat in a hot attic for quite a few years before being transferred to DVD and thence to YouTube. So the picture quality is lousy, in some points nearly unwatchably so. Then again, given the subject matter that may be a feature rather than a bug.

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Electrical Steel: The Material At The Heart Of The Grid

February 15, 2024 by 32 Comments

When thoughts turn to the modernization and decarbonization of our transportation infrastructure, one imagines it to be dominated by exotic materials. EV motors and wind turbine generators need magnets made with rare earth metals (which turn out to be not all that rare), batteries for cars and grid storage need lithium and cobalt, and of course an abundance of extremely pure silicon is needed to provide the computational power that makes everything work. Throw in healthy pinches of graphene, carbon fiber composites and ceramics, and minerals like molybdenum, and the recipe starts looking pretty exotic.

As necessary as they are, all these exotic materials are worthless without a foundation of more familiar materials, ones that humans have been extracting and exploiting for eons. Mine all the neodymium you want, but without materials like copper for motor and generator windings, your EV is going nowhere and wind turbines are just big lawn ornaments. But just as important is iron, specifically as the alloy steel, which not only forms the structural elements of nearly everything mechanical but also appears in the stators and rotors of motors and generators, as well as the cores of the giant transformers that the electrical grid is built from.

Not just any steel will do for electrical use, though; special formulations, collectively known as electrical steel, are needed to build these electromagnetic devices. Electrical steel is simple in concept but complex in detail, and has become absolutely vital to the functioning of modern society. So it pays to take a look at what electrical steel is and how it works, and why we’re going nowhere without it.

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AI-Powered Bumper Sticker Provides Context-Sensitive Urban Camouflage

February 14, 2024 by 17 Comments

While we absolutely support the right of everyone to express their opinions, it seems to us that it’s rarely wise to turn your vehicle into a mobile billboard for your positions. Aside from potentially messing up the finish on your car, what’s popular and acceptable at home might attract unwanted attention while traveling abroad, leading to confrontations that might make your trip a little more eventful than it needs to be.

So why not let technology help you speak your mind in a locally sensitive manner? That’s the idea behind [Pegor]’s “smahtSticker”, an AI-powered bumper sticker that provides the ultimate in context-sensitive urban camouflage. The business end of smahtSticker — we’re going to go out on a limb here and predict that [Pegor] hails from the Boston area — is an 8.8″ (22-cm) wide HDMI display capable of 1920×480 resolution. That goes on the back of your car and is driven by a Raspberry Pi Zero with a GPS module. The Pi grabs a geolocation every second, and if you’ve moved more than 25 feet (7.6 m) — political divisions are at least that granular in the US right now, trust us — it grabs your current ZIP code using GeoPy. That initiates a query to the OpenAI API to determine the current political attitudes in your location, which is used to select the right slogan to display. You’ll fit in no matter where you wander — wicked smaht!

Now, of course, this is all in good fun, and with tongue planted firmly in cheek. The display isn’t weatherized at all, so that would need to be addressed if one felt like fielding this. Also, ZIP codes may be good for a lot of things, but it’s not the best proxy for political alignment, so you might want to touch that part up.

Have A Ball With This 3D Printed Sphere-Making Machine

February 13, 2024 by 19 Comments

Alright, everyone has 30 seconds to get all the jokes out of their system before we proceed with a look at this 3D printed wooden ball polisher.

Ready?

Theoretically, making a sphere out of any material should be easy. All you need to do is pick a point in space inside the material and eliminate everything more than a specified distance from that point. But in practice, sphere-making isn’t quite so simple. The machine [Fraens] presents in the video below is geared more toward the final polish than the initial forming, with a trio of gear motors set 120 degrees apart driving cup-shaped grinding pads.

Constant pressure on the developing sphere is maintained with a clever triangular frame with springs that pre-load the arms and pull them in toward the workpiece, but stop at the desired radius. The three grinding pads are fitted with sandpaper and constantly turn, wearing down the rough piece until it reaches the final diameter. The machine also supports more aggressive tooling, in the form of hole saws that really get to work on the rough blank. Check it out in the video below.

While we appreciate the fact that this is 3D printed, watching the vibrations it has to endure while the blank is still rough, not to mention all the dust and chips it creates, makes us think this machine might not stand up for long. So maybe letting this circular saw jig cut out a rough ball and using this machine for the final polish would be a good idea. Continue reading “Have A Ball With This 3D Printed Sphere-Making Machine” →

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Hackaday Links: February 11, 2024

February 11, 2024 by 4 Comments

Apple’s Vision Pro augmented reality goggles made a big splash in the news this week, and try as we might to resist the urge to dunk on them, early adopters spotted in the wild are making it way too easy. Granted, we’re not sure how many of these people are actually early adopters as opposed to paid influencers, but there was still quite a bit of silliness to be had, most of it on X/Twitter. We’d love to say that peak idiocy was achieved by those who showed themselves behind the wheels of their Teslas while wearing their goggles, with one aiming for an early adopter perfecta, but alas, most of these stories appear to be at least partially contrived. Some people were spotted doing their best to get themselves killed, others were content to just look foolish, especially since we’ve heard that the virtual keyboard is currently too slow for anything but hunt-and-peck typing, which Casey Niestat seemed to confirm with his field testing. After seeing all this, we’re still unsure why someone would strap $4,000 worth of peripheral-vision-restricting and easily fenced hardware to their heads, but hey — different strokes. And for those of you wondering why these things are so expensive, we’ve got you covered.

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Pimp My Pot Redux, Now Cheaper And Even Better

February 10, 2024 by 10 Comments

If there’s one thing we like around here more than seeing an improved version of a project we’ve already covered, it’s when the improvements make the original project cheaper. In the case of this LED ring light for pots and encoders, not only is it cheaper than its predecessors, it’s better looking and easier to integrate into your projects.

Right from its start, [upir]’s “Pimp My Pot” project has been all about bringing some zazzle to rotary controls. Knobs with a pointer and a scale on the panel are okay — especially when they go to eleven — but more lights mean more fun. The fun comes at a price, though; the previous version of “PMP” used an off-the-shelf LED ring light with a unit cost of about $10. Not the end of the world, perhaps, but prohibitive, and besides, where’s the fun in just buying a component specifically made for rotary control indication?

The new version shown in the video below is pin-compatible with the driver board [upir] used for the previous version, which is based on the MAX7219 display driver. Modifying the previous board to accommodate 32 white 0402 LEDs over a 270° arc was no mean feat. [upir] covers both creating the schematic and the PCB layout in some detail, providing his usual trove of tool-chain tips for minimizing the amount of manual work needed.

Wisely, [upir] chose to get his boards assembled by the vendor; getting all those LEDs to line up perfectly is a job best left to the robots. While the board is designed for use with pots that mount on either side, we much prefer mounting the pot’s shaft through the board, as it keeps the LEDs closer to the knob. The final price per board works out to about $6.30 in quantities of ten and falls to a trivial $1.70 each for lots of 1,000. Pretty sweet savings on a pretty sweet-looking build.

This is a cool use of a ring of LEDs, but if you prefer the finger kind, you can make that, too. You can do it the easy way or the hard way.

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