Just In Time For Halloween: Another Talking Skull

October 16, 2018 by Al Williams 4 Comments

It isn’t a unique idea, but we liked [Eric Wiemers’s] take on the classic animated skull for Halloween. In addition to showing you the code and the wiring, the video spends some time discussing what the audio looks like and what has to happen to get it into a format suitable for the Arduino. You can see the spooky video, below.

Of course, this is also a 3D printing project, although the skull is off-the-shelf. We wondered if he felt like a brain surgeon taking the Dremel to the poor skull. To fix the two parts of the device, he used brass threaded inserts that are heat set, something we’ve seen before, but are always surprised we don’t see more often.

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Life Imitates Art: 3D Printed Banksy Frame “Shreds” Oeuvre, Prints Money

October 16, 2018 by Adam Fabio 14 Comments

[Dave Buchanan] is giving the world his own take on the now famous shredding Banksy frame. This version has a few extra features though – like reverse shredding and printing money! Like many of us, [David] was impressed with the Banksy art auction shredding last week. We’re still not sure how he pulled it off, and the jury is still out if it was real, or all some sort of stunt involving the auction house.

[David] took his inspiration straight to CAD software, and designed a miniature version of the frame. A quick trip to the 3D printer and he had the actual frame in hand. He even hand-painted his own copy of Girl with Balloon on canvas. Assembly didn’t quite go as planned, a few parts had to be adjusted — i.e. cut off and hot-glued together. But in the end, the hack worked – the frame would shred and un-shred the painting whenever someone cranked the handle.

If you haven’t guessed yet, [David’s] frame is a version of the classic money printing trick. What looks like two rollers is actually a simple belt drive. The mechanism pulls in one piece of paper while pushing out a hidden piece. It creates the illusion of printing money – or of shredding art. Given Banksy’s sense of humor, we can’t help but wonder if his frame worked the same way.

[David] is working on a re-design of his piece which will be easier to build — so keep an eye on his Reddit thread if you’d like to print your own.

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Wind Turbine Pushes Limits Of Desktop 3D Printing

October 15, 2018 by Tom Nardi 35 Comments

There was a time, not so long ago, when hype for desktop 3D printing as so high that it seemed you could print anything. Just imagine it, and your handy dandy magical 3D printer could manifest it into reality. But now that more people have had first hand experience with the technology, the bubble has burst. Reality has sobered us up a bit, and today we’ve got a much better idea of what can and cannot be printed on a traditional desktop 3D printer.

But that doesn’t mean we aren’t surprised from time to time. As a perfect example, take a look at this almost entirely 3D printed wind turbine designed and built by [Nikola Petrov]. Outside of the electronics, the pole it’s mounted to, and some assorted bits and bobs, he produced all the parts on his own large-format TEVO Black Widow printer. He mentions there are a few things he would do differently if he was to build another one, but it’s hard to find much to complain about with such a gorgeous build.

To be sure, this one isn’t for the 3D printing novice. First of all, you’ll need a printer with a bed that’s at least 370 mm wide just to print the blades. [Nikola] also recommends printing the parts in ABS and coating them with acetone to smooth and harden the outside surfaces. We’d be surprised if you could print such large objects in ABS without a heated enclosure as well, so plan on adding that to your shopping list.

On the flip side though, the electronics are about as simple as they come. The blades are spinning a standard NEMA 17 stepper motor (through a 1:5 gearbox) to produce AC power. This is then fed into two W02M rectifiers and a beefy capacitor, which gives him DC with a minimum of fuss. In theory it should be capable of producing 1A at 12V, which is enough to light LEDs and charge phones. In this design there’s no battery charging circuit or anything like that, as [Nikola] says it’s up to the reader to figure out how to integrate the turbine into their system.

If you don’t think your 3D printing skills are up to the task, no worries. In the past we’ve seen wind turbines built out of ceiling fans, and occasionally, even less.

The 3D Printed Plotter You Didn’t Know You Needed

October 15, 2018 by Tom Nardi 19 Comments

We’ve been seeing an influx of repurposed 3D printers recently. Thrifty hackers have been leveraging cheap 3D printers as a way to bootstrap their builds, on everything from laser engravers to pick and place machines. There’s nothing wrong with that, and honestly when you can get a cheap 3D printer for less than the cost of the components separately thanks to the economies of scale, you’d be foolish not to.

But there’s still something to be said for the classic RepRap mentality of building things using printed parts and smooth rods. Case in point, the largely 3D printed plotter that [darth vader] sent in for our viewing pleasure. This isn’t somebody sicking a pen on the extruder of their open box Monoprice special, this is a purpose built plotter and it shows. In the video after the break you can see not only how well it draws, but also how large of a work area it has compared to a modified 3D printer.

If you know your way around a 3D printer, most of it should look pretty familiar to you. Using the same GT2 belts, steppers, end stop switches, and linear bearings which are ubiquitous in 3D printers, it shouldn’t be difficult to source the parts to build your own. It even uses a Mega 2560 with RAMPS 1.4 running Marlin 1.1.9 for control.

The biggest difference is the physical layout. Since there’s no heavy hotend or extruder assembly to move around, the plotter has a cantilever design which gives it far greater reach. As it only needs to sightly lift the pen off the paper, there’s no need for a complex Z axis with leadscrews either; a simple servo mounted to the end of the arm is used to raise and lift the pen. We especially like the use of a tape measure as strain relief for his wiring, a fantastic tip that we (and many of you) fell in love with last year.

While it’s hard to beat just tossing a pen onto the business end of your desktop 3D printer in terms of convenience, we think it’s pretty clear from this build that the results don’t quite compare. If you want a real plotter, build a real plotter.

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Measuring The Stiffness Of 3D-Printed Parts

October 12, 2018 by Dan Maloney 16 Comments

How do you choose filament when you want strong 3D-printed parts? Like most of us, you probably take a guess, or just use what you have on hand and hope for the best. But armed with a little knowledge on strength of materials, you might be able to make a more educated assessment.

To help you further your armchair mechanical engineer ambitions, [Stefan] has thoughtfully put together this video of tests he conducted to determine the stiffness of common 3D-printing plastics. He’s quick to point out that strength and stiffness are not the same thing, and that stiffness might be more important than strength in some applications. Strength measures how much stress can be applied to an element before it deforms, while stiffness describes how well an element returns to its original state after being stressed. The test rig [Stefan] built for the video analyzes stiffness by measuring the deflection of printed parts under increasing loads. Graphing the applied force versus the deflection gives an indication of the rigidity of the part, while taking the thickness of the material into account yields the bending modulus. The results are not terribly surprising, with polypropylene being the floppiest material and exotic composite filaments, like glass fiber or even “nanodiamond” reinforced PLA coming out as the stiffest. PLA, the workhorse filament, comes in around the middle of the pack.

[Stefan] did some great work here, but as he points out, in the final analysis it almost doesn’t matter what the stiffness and strength of the filament are since you can easily change your design and add more material where it’s needed. That only works up to a point, of course, but it’s one of the many advantages of additive manufacturing.

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Bird Beats Cancer With The Help Of A 3D-Printed Prosthetic

October 11, 2018 by Dan Maloney 12 Comments

It’s a reasonable certainty that 3D-printing is one day going to be a huge part of medicine. From hip implants to stents that prop open blood vessels to whole organs laid down layer by layer, humans will probably benefit immensely from medical printing. But if they do, the animals will get there first; somebody has to try this stuff out, after all.

An early if an unwilling adopter of 3D-printed medical appliances is [Jary], a 22-year-old Great Pied Hornbill, who recently received a 3D-printed replacement for his casque, the large, mostly hollow protuberance on the front the bird’s skull leading out over the upper beak. There’s no known function for the casque, but it had to be removed since cancer was destroying it and [Jary] wouldn’t have fared well post-surgically without one. Working from CT scans, the veterinary team created a model of the casque as well as a jig to guide the saw during surgery. There’s no word on what filament was used, but we’d guess PLA since it’s biocompatible and available in medical grades. The video below shows some of the surgery; it’s interesting to note that the prosthetic started out natural colored but quickly turned yellow as [Jary] preened with oils from glands near his tail feathers, just like a natural casque would.

Hornbills live to about 40 years old, so [Jary] is just middle-aged. Here’s hoping that he lives a long, happy life in return for being a pioneer in 3D-printing for medical and surgical appliances.

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The 3D Printed Guitar

October 10, 2018 by Brian Benchoff 6 Comments

We just wrapped up the Musical Instrument Challenge in the Hackaday Prize, and that means we’re sorting through a ton of inventive electronic musical instruments. For whatever reason we can’t seem to find many non-electronic instruments. Yes, MPCs are cool, but so are strings and vibrating columns of air. That’s what makes this entry special: it’s a 3D printed physical guitar. But it’s also got a hexaphonic pickup, there are lights in the fretboard, and it talks to a computer for PureData processing.

First, the construction of this guitar. It’s mostly 3D printed, with the ‘frame’ of the body made in a Creality 3D printer. It’s a bolt-on neck with a telecaster body, but the core of this guitar — where the pickups and bridge attach — are made out of aluminum extrusion. Another piece of aluminum extrusion runs down the neck, which is clad in a 3D-printed ‘back’ that looks ‘comfortable enough’. The headstock is bolted onto the end of this neck, and it seems reasonably tolerant of having a hundred pounds or so of strings pulling on it. The bridge is also 3D printed, with the saddles integrated into the print. Conventional wisdom says this would sound terrible, but nylon saddles were a thing back in the day, so we’re just going to roll with it.

The electronics are where this project really shines. The pickup is a salvaged Roland GK3 hexaphonic deal, with six outputs for each string. This is sent into a Teensy with an audio path for each individual string. Audio processing happens in the guitar, and latency is under five milliseconds, which is quick enough to not be a terrible distraction.

Except for synths and drum machines and computers, the last fifty or so years of technological progress hasn’t really made it to the world of musical instruments. Guitarists, especially, are technophobes who hate everything invented after 1963. While the neck of [Frank]’s ElektroCaster probably doesn’t feel great, this is a really interesting instrument and a great entry to the Hackaday Prize.