Up In The Sky… It’s A Bird… It’s A Drone… Oh Yeah, It’s A Drone

June 21, 2022 by 15 Comments

One staple of science fiction is the ornithopter, which is a plane with moving wings. While these haven’t proved very practical in the general sense, a recent paper talks about mimicking natural wings changing shape to improve maneuverability in drones and other aircraft. In particular, the paper talks about how the flight performance of many birds and bats far exceeds that of conventional aircraft.

The technical term for being more maneuverable than a conventional aircraft is, unsurprisingly, called supermaneuverability. Aircraft performing things like the Pugachev Cobra maneuver (watch the video below, or the latest Top Gun movie) require this type of operation, and with modern aircraft, this means using thrust-vector technology along with unstable airframes and sophisticated computer control. That’s not how birds or bats operate, though, and the paper uses modern flight simulation techniques to show that biomimicry and thrust vector technology don’t have to be mutually exclusive.

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No Tool Left Behind With The Help Of Homemade Shadow Boards

June 21, 2022 by 38 Comments

Shadowed tool storage — where a tool outline shows at a glance what’s missing from storage — is a really smart way to keep your shop neat. They’re also super important for cases where a tool left behind could be a tragedy. Think, where’s-that-10-mm-socket-while-working-on-a-jet-engine? important. (It’s always the 10-mm socket.)

But just because shadow boards are smart, doesn’t mean they’re easy to make. That’s why [Scott Prince] came up with this semi-automated method for making toolbox shadow boards. The job of tracing around each tool on some sort of suitable material and cutting out the shapes seems straightforward, but the trick comes in organizing the outlines given the space available and the particular collection of tools.

[Scott]’s method starts with capturing images of each individual tool. He used a PiCam and a lightbox housed, strangely enough, in a storage bench; we’d love to hear the full story behind that, but pretty much any digital camera would do for the job. After compensating for distortion with OpenCV, cropping the images, and turning the image into a vector outline of the tool, [Scott] was left with the task of putting the tools into logical groups and laying them out sensibly. After tweaking the tool outlines and adding finger cutouts for easy pickup, [Scott] put his CNC router to work. He chose to use a high-density polyethylene product made by his employer, which looks fantastic, but MDF would work fine too.

We have to admit to a fair degree of toolbox envy now that we’ve seen what shadow boards can do. We’re a bit torn, though — [Zach Friedman]’s Gridfinity storage system has a lot going for it, too.

Wonderful Foldable Printable Dodecahedron

June 20, 2022 by 14 Comments

Debra Ansell of [GeekMomProjects] fame came up with a neat, 3D design that prints flat and then folds up into everyone’s favorite Platonic solid: a D12.

Why would you want to do this? Well, folding up your 3D prints gives you a third dimension “for free” without using all that support material. Here, all of the outside faces of the dodecahedron are printed flat against the build plate, which is probably the nicest side of your prints. And embedding LEDs in the resulting shape would probably be easy because they’re all in plane. And speaking of LEDs, we kinda expected to see them here, given Debra’s motto: “LEDs improve everything” — that part is up to you.

Debra notes that she likes PETG instead of PLA for the extra strength in the thin-printed hinges, and we’d bet that your printer’s tolerances will need to be spot on for the clips that hold the whole thing together. (We’d be tempted to apply a little super-duper glue.)

As always with Debra’s projects, there’s some creative solutions on display here that’ll help you out whether you need a D12 or a D20, so give it a look!

Thanks [Peter] for the tip.

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Blinking An Arduino LED, In Julia

June 20, 2022 by 11 Comments

The Julia programming language is a horrible fit for a no-frills microcontroller like the ATMega328p that lies within the classic Arduino, but that didn’t stop [Sukera] from trying, and succeeding.

All of the features that make Julia a cool programming language for your big computer make it an awful choice for the Arduino. It’s designed for interactivity, is dynamically typed, and leans heavily on its garbage collection; each of these features alone would tax the Mega to the breaking point. But in its favor, it is a compiled language that is based on LLVM, and LLVM has an AVR backend for C. Should just be a simple matter of stubbing out some of the overhead, recompiling LLVM to add an AVR target for Julia, and then fixing up all the other loose ends, right?

Well, it turns out it almost was. Leaning heavily on the flexibility of LLVM, [Sukera] manages to turn off all the language features that aren’t needed, and after some small hurdles like the usual problems with volatile and atomic variables, manages to blink an LED slowly. Huzzah. We love [Sukera’s] wry “Now THAT is what I call two days well spent!” after it’s all done, but seriously, this is the first time we’ve every seen even super-rudimentary Julia code running on an 8-bit microcontroller, so there are definitely some kudos due here.

By the time that Julia is wedged into the AVR, a lot of what makes it appealing on the big computers is missing on the micro, so we don’t really see people picking it over straight C, which has a much more developed ecosystem. But still, it’s great to see what it takes to get a language designed around a runtime and garbage collection up and running on our favorite mini micro.

Thanks [Joel] for the tip!

3D Printed Concrete Beam Improves Sustainability

June 20, 2022 by 38 Comments

Many of the 3D printed houses and structures we’ve seen use concrete and are — frankly — a little underwhelming. Making big squares out of concrete isn’t that hard and while we are sure there is some benefit, it isn’t overwhelming. [Andy Coward] apparently felt the same way and set out to find ways that 3D printing could offer unique benefits in building structures. The result: a beam that would be difficult to create with conventional techniques but is easy to make with a printer. The advantage is that it uses 78% less concrete than a conventional beam with the same properties.

The key is that in a normal beam, not much of the concrete is bearing a significant load. It is simply there because you need some concrete on one side of the beam and then some more on the other side. In the center, surprisingly little of the concrete actually supports anything. The new beam takes advantage of this along with a steel reinforcement at a strategic point. Still, it uses 70% less steel than a typical reinforced beam.

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Don’t Mind If I Ski-Do

June 20, 2022 by 6 Comments

There is an age-old tradition among hackers of just making it yourself. Whether the real thing is too expensive or you think you can make a better one, the itch strikes, and it can quickly spread. [Homemade Madness] has quite the itch as he builds his own jetski.

What is a jetski but a boat with a shell on top? In an earlier video, he created a boat out of plywood and, after the usual steps of fiberglass and sealing, was proud to float around in his relatively normal-looking boat. But now that he had a working bottom, it was time to return to CAD. He printed out templates for all various shapes he would need, each labeled with a different designator, and glued them to the plywood. No fancy CNC here, just a steady hand and a jigsaw. We love the professional build instructions he compiled for himself that detail in LEGO-like quality exactly how each piece slots into where and in what order to do them. In addition to the top layer of the jetski, he also designed a stand for the boat to rest on while he made it, which is just going the extra mile. A ceiling-mounted winch made it easy to lift the ship into position. Next, he connected all the various framing pieces with PU glue. Thin plywood acted as cladding on top of the skeleton. Filling, sanding, and fiberglass overlaid the structure, making it waterproof. More sanding and some primer later, and it was ready for another water test.

He designed a version with an outboard motor, but he’s trying to build one with a built-in jet drive. So we’re looking forward to seeing the next step and him flying around on his custom watercraft. But what he has already done is quite impressive. If you’re looking for something a little smaller to pull you around the water, why not take a look at this little 3d printed tug boat? Video after the break.

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Scrambling Pocket Calculators Made Easy With EMP Box V2

June 20, 2022 by 47 Comments

[Rostislav Persion] has for some time been interested in making small, portable EMP devices capable of interfering with nearby electronics. In these EMP devices, high voltage is used to create a portable spark gap generator, whose operation in turn creates electromagnetic pulses capable of resetting or scrambling nearby electronics such as pocket calculators.

Bridging adjacent holes narrows the spark gap, resulting in more frequent pulses.

His original EMP box designs relied on spark gaps constructed from metal screws threaded into a clear plastic insulator, but this newest design ditches fussy screw adjustments and relies on perfboard. By cutting out a single row of plated perfboard holes and soldering the high voltage terminals to each end, the empty holes in between form the essential parts of a spark gap.

It’s even adjustable: one simply bridges adjacent holes with solder to effectively decrease the gap. As for generating the high voltage itself, a DC voltage multiplier from Amazon takes care of that. Watch the device reset some calculators in the short video below.

Looking for high-voltage experiments that aren’t so sketchy? Get yourself a Van de Graff generator, some metal balls, and a little bit of oil, and make some art.

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