2018’s Hottest Accessory Is A 3D Printed Air Raid Siren

Some say the spectre of global nuclear annihilation is closer than ever before. What better time to head to the workshop to prepare for the coming apocalypse? [MrExpert] is here with the build you need – an air raid siren you can print at home.

It’s a simple build, which makes it fun and accessible for just about anyone with a 3D printer. Rotational power is provided by a brushless outrunner motor hooked up to an ESC, controlled with a servo tester. The rotor and frame for the parts are 3D printed, and held together with a handful of standard fasteners.

Initial testing proves that yes, it does work and generates a rather earsplitting tone. The second revision improves upon this somewhat. However, the key to getting that authentic sound is in the sweep of the tone. By replacing the servo tester with an Arduino or other micro that can generate smoothly sweeping pulses to ramp the rotational speed up and down, you’ll get much closer to that genuine the-sky-is-falling timbre.

It’s certainly not rocket science, and would make a great project to whip up with the kids on a rainy weekend. While you’re at it you can share the wisdom behind the duck and cover technique, but maybe save the geopolitical rants for when they’re a bit older. We’ve seen air raid siren builds before, too – like this sturdy wooden unit.

Reverse Engineering Nintendo Labo Waveform Cards

The Nintendo Switch portable gaming system is heavily locked down to prevent hacking, but the Labo add-on looks like it might be a different matter. The Labo is a series of add-on devices made of cardboard that does things like turn the Switch into a musical keyboard that plays a waveform on a card that you slot in. [Hunter Irving] decided to try a bit of reverse engineering on these cards to see if he could 3D print his own. Spoilers: he could.

[Hunter] started by taking one of the cards that come with the Labo and looking at the layout. These cards are, like the rest of the Labo, very simple: they are just shaped pieces of card that fit into the back of the keyboard add-on. When you press a button, the Switch camera reads the card to create the waveform. So, the process involved figuring out the required dimensions of the card to create a template. [Hunter] then created simple waveforms (square, sine, sawtooth) in Inkscape, and used this to create a 3D printable waveform card. A quick bit of 3D printing later, he had several cards ready, and these worked without problems. As well as the synthetic waveforms, he tried real ones, such as an organ, taking the waveform shape from the zoomed-in sample and using that to print. This post describes the process nicely and offers downloads of 9 sample cards and a template to create your own.

We suspect that this is only scratching the surface of what can be done with the Switch, Labo, and some ingenuity. Unlike the Switch itself, the Labo seems to be built for hacking, using simple, easy to use components to create surprisingly complex mechanisms that could be adapted for any number of purposes.

We’re sure this isn’t the only Labo hack we’ll be covering over the coming year. Not sure what all the fuss is about? Read our reporting on its arrival.

Beat This Mario Block Like It Owes You Money

People trying to replicate their favorite items and gadgets from video games is nothing new, and with desktop 3D printing now at affordable prices, we’re seeing more of these types of projects than ever. At the risk of painting with too broad a stroke, most of these projects seem to revolve around weaponry; be it a mystic sword or a cobbled together plasma rifle, it seems most gamers want to hold the same piece of gear in the physical world that they do in the digital one.

But [Jonathan Whalen] walks a different path. When provided with the power to manifest physical objects, he decided to recreate the iconic “Question Block” from the Mario franchise. But not content to just have a big yellow cube sitting idly on his desk, he decided to make it functional. While you probably shouldn’t smash your head into the thing, if you give it a good knock it will launch gold coins into the air. Unfortunately you have to provide the gold coins yourself, at least until we get that whole alchemy thing figured out.

Printing the block itself is straightforward enough. It’s simply a 145 mm yellow cube, with indents on the side to accept the question mark printed in white and glued in. A neat enough piece of decoration perhaps, but not exactly a hack.

The real magic is on the inside. An Arduino Nano and a vibration sensor are used to detect when things start to get rough, which then sets the stepper motor into motion. Through an ingenious printed rack and pinion arrangement, a rubber band is pulled back and then released. When loaded with $1 US gold coins, all you need to do is jostle the cube around to cause a coin to shoot out of the top.

If this project has got you interested in the world of 3D printed props from the world of entertainment, don’t worry, we’ve got you covered.

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3D Printing Watertight Containers

Most normal 3D prints are not watertight. There are a few reasons for this, but primarily it is little gaps between layers that is the culprit. [Mikey77] was determined to come up with a process for creating watertight objects and he shared his results.

The trick is to make the printer over extrude slightly. This causes the plastic from adjacent layers to merge together. He also makes sure there are several layers around the perimeters.

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3D Printer Time Lapse Videos Ditch The Blur

Example output of Octolapse with the print head absent from the images.

Most time-lapse videos of 3D prints show a steadily growing print with a crazy blur of machine movement everywhere else. This is because an image is captured at a regular time interval, regardless of what’s physically going on with the machine. But what if images were captured at consistent machine positions instead? [FormerLurker]’s Octolapse plugin for OctoPrint came out of beta recently and does exactly that, and the results are striking. Because OctoPrint knows where a 3D printer’s print head is at all times, it’s possible for a plugin to use this information to create time-lapse videos where the print head position is consistent instead of a crazy blur, or even have the print head absent from the shot altogether.

[FormerLurker] had originally created stabilized time lapses by hand editing G-code, which had great results but was inefficient and time-consuming. This plugin is the result of his work at automating and enhancing the process, and is also his first serious open source programming project. We’ve covered upgrading a 3D printer with OctoPrint before, and the plugins functionality of OctoPrint means features can be added independently from the core system, which itself largely remains a one-woman effort by creator and maintainer [Gina Häußge].

 

Can You 3D Print An Axe?

3D printers hit the scene in a big way in the last decade, and thanks to the constant improvements that we’ve seen since then you can now get a decent one, assembled or as a kit, for a reasonable price. The one major drawback is that almost all of these printers are limited to printing in plastic, which has its obvious limitations. Printing in metal seems like the next logical step, and a group from Michigan Tech has created something that is accessible to most of us. Spoiler: they used plastic and metal printing to print a functioning axe.

Untill now, most metal printers have used a process like laser sintering to achieve the desired effect. This group uses a much more common tool: a MIG welder. MIG welders work by passing a wire through the welding handle, which would normally used as the filler material for the weld. If you use the wire for laying down material rather than for welding specifically, you can build up material on a surface in essentially the same way that a printer that prints plastic would.

From there, all that’s needed is to attach the MIG welder to a CNC machine and get to printing. The team has produced some great results so far, including some metal braces and farm implements, so hopefully their work leads to another revolution in 3D printing for the masses. We think it’s high time.

3D Print A Thinner Car Key

Almost all modern cars come with keyless entry, some even come with keyless start. Of course, the price you pay for this technology is a bulky plastic keyfob that is an absolute pain to remove from your pockets, and generally spoils the lines of your carefully chosen outfit. [Jeremy] decided enough was enough.

The project begins with a careful disassembly of the original key. This is important to avoid damaging the PCB inside, particularly if there are any delicate wire links between different sections of the keyfob. With the piece disassembled, it was then time to start designing a replacement encasement to hasten escapement while pacing the pavement.

The 3D printer really is the perfect tool for the job here, and [Jeremy] employs it well. With this being a proximity-based keyfob, the buttons are only necessary if you want to operate the locks at a distance. They simply took up too much vertical space, so they had to go. In the end, with a redesigned housing for the PCB, and while retaining the backup mechanical key, the new fob is just 11mm, down from 18mm – a nearly 40% saving in thickness!

It’s a tidy way to clean up your pockets and make life easier. We’ve seen similar work before, too.