Hackaday Links: October 31, 2021

October 31, 2021 by Dan Maloney 17 Comments

Global supply chain issues are beginning to hit closer to home for the hacker community, as Raspberry Pi has announced their first-ever price increase on their flagship Pi 4. The move essentially undoes the price drop on the 2GB version of the Pi 4 that was announced in February, and sets the price back up from $35 to $45. Also rolled back is the discontinuation of the 1GB version, which will now be available at the $35 price point. The announcements come from Eben Upton himself, who insists the price increase is only temporary. We applaud his optimism, but take it with a grain of salt since he also said that 2021 production across the board will stay at the seven million-unit level, which is what they produced in 2020. That seems to speak to deeper issues within the supply chain, but more immediately, it’s likely that the supply of Pi products will be pinched enough that you’ll end up paying above sticker price just to get the boards you need. Hope everyone is stocked up.

On the topic of supply chain issues and their threat to Christmas gift-giving, here’s one product we hope is stranded in a container off Long Beach or better still, bobbing along in the Strait of Juan De Fuca: a toddler’s toy telephone that actually makes and receives calls. Anyone born in the last 60 years probably had one of the Fisher-Price Chatter telephone, a toy that in its original form looked like a desk telephone on wheels that was dragged behind the child, popping along and providing endless hours of clicky amusement as kids twisted the dial and lifted the receiver. Come to think of it, the Chatter telephone may be as close to a dial phone as anyone born since 1990 may have come. Anyway, some genius stuck a Bluetooth module into the classic phone to let it hook up to an app on an actual phone, allowing kids (or more likely their nostalgia-soaked parents) to make and receive calls. It’s actually priced at a reasonable $60, so there might be some hacking potential here.

Also tangential to supply chains, we stumbled across a video guide to buying steel that might interest readers. Anyone who has seen the displays of steel and other metals at the usual big-box retailers might wonder what the fuss is, but buying steel that way or ordering online is a great way to bust a project’s budget. Fabricator and artist Doug Boyd insists that finding a local steel supplier is the best bang for your buck, and has a bunch of helpful tips for not sounding like a casual when you’re ordering. It’s all good advice, and would have helped us from looking foolish a time or two at the metal yard; just knowing that pipe is measured by inside diameter while tubing is measured by outside dimensions is worth the price of admission alone.

With all the money you save on steel and by not buying Raspberry Pis, perhaps you’ll have a couple of hundred thousand Euros lying around to bid on this authentic 1957 Sputnik I satellite. The full-scale model of Earth’s first artificial satellite — manhole covers excluded — was a non-flown test article, but externally faithful to the flown hardware that kicked off the first Space Race. The prospectus says that it has a transmitter and a “modern power supply”; it’s not clear if the transmitter was originally part of the test article or added later. The opening bid is €85,000 and is expected to climb considerably.

And finally, there’s something fascinating about “spy radios,” especially those from the Cold War era and before, when being caught with one in your possession was probably going to turn out to be a very bad day. One such radio is the Radio Orange “Acorn” receiver, which is in the collection of the Crypto Museum. The radio was used by the Dutch government to transmit news and information into the occupied Netherlands from their exile in London. Built to pass for a jewelry box, the case for the radio was made from an old cigar box and is a marvel of 1940s miniaturization. The radio used three acorn-style vacuum tubes and was powered by mains current; another version of the Radio Orange receiver was powered by a bike dynamo or even a water-powered turbine, which could be run from a tap or garden hose. The video below shows the water-powered version in action, but the racket it made must have been problematic for its users, especially given the stakes.

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Heavy Metal Lathe Build Doesn’t Spare The Steel

October 27, 2021 by Dan Maloney 22 Comments

It’s common wisdom that the lathe is the essential machine tool, and the only one that can make copies of itself. While we won’t argue the primacy of the lathe in the machine shop, this scratch-built, heavy-duty lathe gives the lie to the latter argument — almost.

We’re used to seeing homebrew lathes, of course, and we’ve featured more than a few of them before. But two things make [Jornt]’s build stand out: how few specialized tools were needed to build it, and the sheer size and bulk of the finished product. Where most homebrew lathes tend to be the bench top variety and feature cast aluminum parts, [Jornt] went with steel for his build, and a lot of it. The base and bed of the machine are welded from scrap steel I-beams, and the ways are made from angle iron that has been ground flat with a clever jig to hold an angle grinder. The angle grinder plays a prominent role in the build, as do simple tools like a hand drill, files, and a welder — and yes, the unfinished lathe itself, which was used to bore out the bearing blocks for the headstock.

The completed lathe, powered by a treadmill motor in a way that [Jeremy Fielding] would no doubt endorse, comes in at a beefy 450 kg. It honestly looks like something you could buy from a catalog, and has most of the features of commercial machines. One thing we’d love to see on this lathe is the electronic lead screw that [James Clough] developed for his off-the-shelf lathe.

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Simple Tip Helps With Powder Coating Perfection On Difficult Parts

July 24, 2021 by Dan Maloney 8 Comments

To say that that the commercially available garden path lights commonly available at dollar stores are cheap is a vast overstatement of their true worthlessness. These solar-powered lights are so cheaply built that there’s almost no point in buying them, a fact that led [Mark Presling] down a fabrication rabbit hole that ends with some great tips on powder coating parts with difficult geometries.

Powder coating might seem a bit overkill for something as mundane as garden lights, but [Mark] has a point — if you buy something and it fails after a few weeks in the sun, you might as well build it right yourself. And a proper finish is a big part of not only getting the right look, but to making these totally un-Tardis-like light fixtures last in the weather. The video series below covers the entire design and build process, which ended up having an aluminum grille with some deep grooves. Such features prove hard to reach with powder coating, where the tiny particles of the coating are attracted to the workpiece thanks to a high potential difference between them. After coating, the part is heated to melt the particles and form a tough, beautiful finish.

But for grooves and other high-aspect-ratio features, the particles tend to avoid collecting in the nooks and crannies, leading to an uneven finish. [Mark]’s solution was to turn to “hot flocking”, where the part is heated before applying uncharged coating to the deep features. This gets the corners and grooves well coated before the rest of the coating is applied in the standard way, leading to a much better finish.

We love [Presser]’s attention to detail on this build, as well as the excellent fabrication tips and tricks sprinkled throughout the series. You might want to check out some of his other builds, like this professional-looking spot welder.

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Put The Perfect Point On Your Tungstens With This Die Grinder Attachment

March 29, 2021 by Dan Maloney 14 Comments

Aspiring TIG welders very quickly learn the importance of good tungsten electrode grinding skills. All it takes is a moment’s distraction or a tiny tremor in the torch hand to plunge the electrode into the weld pool, causing it to ball up and stop performing its vital function. Add to that the fussy nature of the job — tungstens must only be ground parallel to the long axis, never perpendicular, and at a consistent angle — and electrode maintenance can become a significant barrier to the TIG beginner.

A custom tungsten grinder like this one might be just the thing to flatten that learning curve. It comes to us by way of [The Metalist], who turned an electric die grinder into a pencil sharpener for tungsten electrodes. What we find fascinating about this build is the fabrication methods used, as well as the simplicity of the toolkit needed to accomplish it. The housing of the attachment is built up from scraps of aluminum tubing and sheet stock, welded together and then shaped into a smooth, unibody form that almost looks like a casting. Highlights include the mechanism for adjusting the angle of the grind as well as the clever way to slit the body of the attachment so it can be clamped to the nosepiece of the die grinder. We also thought the inclusion of a filter to capture tungsten dust was a nice touch; most TIG electrodes contain a small amount of lanthanum or thorium, so their slight radioactivity is probably best not inhaled.

We love builds like this that make a tedious but necessary job a little quicker and easier to bear, and anything that stands to make us a better welder — from simple purpose-built fixtures to large-scale rotary tables — is OK in our book.

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Denim Sunglasses Frames Use A Wicked Set Of Jigs

July 30, 2020 by Mike Szczys 11 Comments

An obligatory “Future’s so bright I gotta wear… denim” joke is the only way to kick off this article. Sorry!

Now that that’s out of the way, how would you turn your own blue jeans into sunglasses? Well you wouldn’t, unless you’ve built an intricate jig for assembling sunglasses frames like [Mosevic] has done. Boiled down, this is like making parts out of carbon fiber, except you swap in denim for the carbon fiber. Several layers of blue jean material are layered in a mold and impregnated with resin. Once hardened, parts can be milled or laser cut from this stock and then assembled into the frames all of the hipsters are after.

For us its the assembly jig that’s so interesting to see. [Mosevic] shared it in an unlisted video of an update to the Kickstarter campaign which ran at the end of 2019. The jig is used to align machined parts into stack ups that include brass reinforcement and pins to align layers, as well as the joining for the three parts of the frame via the metal hinges. Most of the jig is made from machined plywood. The plates that hold the three parts of the frame, the “frame front” and the two “temples” in eyeglass parlance, are interchangeable so that the same jig can be used to assemble several variants of the frame design. The most notable non-plywood part of the jig are two metal clamps that hold the hinge into the frame front as the glue dries, holding a couple of tiny chunks of denim/resin block in place.

Here you can see the jig with all clamps fully closed. There is not an insignificant amount of time just getting the parts into this jig. But parts still need quite a bit of cleanup after this process to sand, shape, and polish all edges and surfaces of the frames. And of course you have to figure in the time it took to make the parts that went into the jig in the first place. The finished frames are gorgeous, but we have a lot more respect having seen what it takes to pull it off.

Now if you like your glasses like George Washington liked his false teeth, here’s how you can pull a set of shades out of your woodshop.

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DIY Lambo That Made The Real Lamborghini Take Notice

January 18, 2020 by Danie Conradie 33 Comments

When you start sharing your projects with the world, you never know who might take notice. [Sterling Backus] and his son [Xander] have been building a functional Lamborghini Aventador look alike in their garage, and the real Lamborghini company caught wind of it and decided to turn it into an awesome Christmas ad.

Named the AXAS Interceptor by its creators, the car is built from scratch around a custom tubular space frame chassis. Most of the body panels are 3D printed and then skinned with carbon fibre, with a few sheet metal panels mixed in. The interior is mix of parts from other cars and aftermarket components, with 3D printing to pull everything together. The drivetrain consists of an engine from a Corvette, a transaxle from a Porsche 996, with the rest of the chassis components being either aftermarket or custom-fabricated pieces.

[Sterling] got an unexpectedcall from Lamborghini, and they arranged to secretly sneak a real Aventador into the garage in the dead of night to surprise the rest of the family, and let them borrow it for a few weeks. Lamborghini got some marketing out of it, which most people would probably agree is a pretty good deal. We would admit that we’re quite envious.

The car is driveable, but still many hours from being complete. [Sterling] admits that he is no car building professional, but we’re impressed by what he has been able to achieve so far with this ambitious project, and we’re looking forward to the finished product.

If you want to get your feet wet with your first project car, here’s how you pick one.

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A Self-Healing, Stretchable Electronic Skin

December 4, 2019 by Sharon Lin 4 Comments

In a report published by Science Advances, a research team from the United States and Korea revealed a strain-sensitive, stretchable, and autonomous self-healing semiconductor film. In other words, they’ve created an electronic skin that’s capable of self-regulation. Time to cue the ending track from Ex Machina? Not quite.

Apart from the inevitable long timeline it will take to see the material in production, there are still challenges to improve sensing for active semiconductors. The methods used by the team – notably using a dynamically cross-linked blend of polymer semiconductor and self-healing elastomer – have created a film with a gauge factor of 5.75×10^5 at full strain. At room temperature, even with fracture strains, the material demonstrated self healing.

The technique mimics the self healing properties of human skin, accelerating the development of biomedical devices and soft robots. While active-matrix transistor array-based sensors can provide signals that reduce crosstalk between individual pixels in electronic skin, embedding these rigid sensors and transistors into stretchable systems causes mechanical mismatch between rigid and soft components. A strain-sensing transistor simplifies the process of fabrication, while also improving mechanical conformability and the lifetime of the electronic skin.

The synthetic skin was also shown to operate within a medically safe voltage and to be waterproof, which will prevent malfunctions when placed in contact with ionic human sweat.

[Thanks Qes for the tip!]