Month: June 2019

Experiments In Creating The Best Epoxy Granite

June 1, 2019 by 59 Comments

If you want a big CNC machine you need a strong, vibration-resistant base. They build bells out of metal, so that might not be the best if you want something that doesn’t shake. Epoxy granite is your best bet, but what epoxy granite is the best? That’s the question [Adam Bender] answered in a series of experiments that resulted in a great-looking CNC machine.

While this is a project that resulted in a completed base for a CNC machine, this is also an experiment to determine the best formula for creating your own epoxy granite. The purpose of the experiment is effectively to determine the best-looking epoxy granite and uses four variables in the composition of this composite. Play sand, gravel, dye (in the form of iron oxide and liquid epoxy dye), and two-part epoxy were used to create seven different samples. Samples using rock didn’t turn out that great and still had trapped air. This was true even if the epoxy was put in a vacuum chamber for degassing. The winning combination turned out to be a mix of 80% sand and 20% epoxy with a bit of black dye, vibrated for 30 minutes on a DIY shaker table.

With the correct formula for epoxy granite, [Adam] set up his mold and waxed everything liberally. The internal skeleton, or what the CNC machine will be bolted to, is assembled inside the mold and the epoxy is poured in. The result is fantastic, and an excellent base for a machine that turns metal into chips. You can check out the video below.

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3D Prints Turn Any Keyboard Isomorphic

June 1, 2019 by 4 Comments

In the history of weird musical instrument interfaces, isomorphic keyboards are a favorite. These keyboards look like a grid of buttons, but when you play them, the relative shapes of chords are always the same. The benefit? Just say no to five hundred years of clavier tradition. It looks cool, too. Theoretically, it’s easier to play independent of whatever key you’re in. [John Moriarty] has built one of these isomorphic keyboards, and unlike everything we’ve ever seen, there are no electronics. It’s all 3D printable and turns any MIDI keyboard into an isomorphic keyboard.

We have seen isomorphic (piano) keyboards before, from a slew of Cherry keyboard switches to a bunch of arcade buttons. There is one downside to these builds, and that is that it’s really just building a MIDI controller. [John]’s build is simply a 3D printable overlay for a traditional piano that turns any standard keyboard into an isomorphic keyboard. The advantage being that this is really just a few pounds of plastic to be printed out and not a mess of wiring and electronics. Simple, removable, reversible. Not bad.

This keyboard effectively adds two differently colored keytops to each key on a keyboard. The best explination of how this keyboard works is in this video, but the basic idea is that all the note names are grouped together by color; C flat, C natural, and C sharp are all blue, for example. This means a third interval is two colors away, and a minor third is two colors to the right and one ‘row’ down. Yeah, it’s weird but that’s what an isomorphic keyboard is.

Since this is just a bunch of 3D printed parts meant to fit on any piano keybed, this is something that’s extremely easy to replicate. All the files for this keyboard overlay are available on Thingiverse, and [John] is offering to print these key tops for others without a 3D printer.

Paper Strandbeest Is Strong Enough To Walk

June 1, 2019 by 10 Comments

Most readers will be familiar with the work of the Dutch artist Theo Jansen, whose Strandbeest wind-powered mechanical walking sculptures prowl the beaches of the Netherlands. The Jansen linkage provides a method of making machines with a curious but efficient walking gait from a rotational input, and has been enthusiastically copied on everything from desktop toys to bicycles.

One might think that a Jansen linkage would be beyond some materials, and you might be surprised to see a paper one. Step forward [Luis Craft] then, with a paper walking Strandbeest. Designed in Blender, cut on a desktop CNC paper cutter, and driven by a pair of small robots linked to an Arduino and controlled by a Bluetooth link, it has four sets of legs and can push around desktop items. We wouldn’t have thought it possible, but there it is.

He claims that it’s an origami Strandbeest, but we’re not so sure. We’re not papercraft experts here at Hackaday, but when we put on our pedantic hat, we insist that origami must be made of folded paper in the Japanese style rather than the cut-and-glue used here. This doesn’t detract from the quality of the work though, as you can see in the video below.

We think this is the first paper Strandbeest we’ve seen, but we’ve brought you countless others over the years. Here’s [Jansen]’s latest, wave-like take on the idea.

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