A 3D-Printed Bass Guitar

February 29, 2020 by Jenny List 1 Comment

A visit to the hardware hacking area of the recent Hacker Hotel hacker camp in the Netherlands would bring plenty of interesting pieces of hardware to delight the eye. Among them though was one to delight the ear, and on hearing it we asked whether its creator could put it online so we could share it with you. [XDr4g0nX]’s bass guitar is 3D printed, and while it still contains some non-3D-printed parts it’s still a very effective musical instrument.

This is not the first model he’s produced, he told us, an earlier guitar was entirely 3D-printed but proved not to be rigid enough. Tuning such an instrument merely resulted in its bowing out of shape and becoming unplayable as well as out of tune. This one has hefty steel bars for rigidity, though it uses a Yamaha neck rather than 3D-printing the whole instrument. The main body of the instrument has to be printed in multiple parts and epoxied together, which he’s done without some of the ugly seams that sometimes disfigure prints of this nature.

Having heard it, we’d be hard pressed to tell it wasn’t a more traditional guitar, but then again since people have made guitars from all kinds of scrap it’s not the first home build we’ve encountered.

Self-Playing Kalimba V2 Thanks To Readers Like You

February 25, 2020 by Kristina Panos 12 Comments

Would you like to know the great thing about this community we have here? All the spitballing that goes on every day in the comments, the IO chat rooms, and in the discussion threads of thousands of projects. One of our favorite things about the Hackaday universe is that we help each other out, and because of that, our collective curiosity pushes so many designs forward.

[Gurpreet] knows what we’re talking about. He’s back with version two of his self-playing kalimba, driven as strongly as ever by the dulcet tones of the Avatar theme. Now the robo-kalimba is rocking two full octaves, and thanks to your comments and suggestions, has relocated the servos where they can’t be picked up by the soundboard.

We gasped when we saw the new mechanism — a total of 15 rack and pinion linear actuators that make the kalimba look like a tiny mechanical pipe organ. Now the servos float, fixed into a three-part frame that straddles the sound box. [Gurpreet] melted servo horns to down to their hubs rather than trying to print something that fits the servos’ sockets.

Thumb your way past the break to check out the build video. [Gurpreet] doesn’t shy away from showing what went wrong and how he fixed it, or from sharing the 3D printering sanity checks along the way that kept him going.

Plucking kalimba tines is a difficult problem to solve because they’re stiff, but with timbre sensitive to many degrees of pressure. A slightly easier alternative? Make a toy player piano.

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Introducing The XFM2: A New FM Synthesizer Board

February 22, 2020 by Maya Posch 29 Comments

[René Ceballos] contacted us about the new XFM2 FM synthesizer board, successor to the XFM that we covered on Hackaday last year. In addition to changing FPGAs from a Spartan 6 to an Artix-7 35, the DAC was also upgraded from 16 to 24 bits. Since the project is based around two easily available boards for the FPGA and DAC functionality, it is something that should be easy for anyone to recreate.

The project consists of a lower board that features the opto-isolated MIDI-input port, a 24LC1025 EEPROM, and a few passives, on top of which are mounted the Adafruit UDA1334A-based I2S decoder board and a Digilent Cmod A7-35T, containing the Xilinx XC7A35T-1CPG236C Artix-7 FPGA. [René] has made a schematic and BOM available on the XFM2 page. Total part cost should be about $99.

A user manual, installation guide, and the binaries that have to be loaded into the FPGA – using the provided instructions – are all made available. Unfortunately no HDL source is provided, but that shouldn’t take away from the fun of assembling an FM synthesizer board like this.

[René ] said that based on the feedback to the XFM project, he is now working on a visual user interface for the board. Once this is all working and depending on the feedback from XFM2 users, he may decide to start a crowdfunding campaign.

LEGO Microtonal Guitar: Building Blocks Of Music Theory

February 20, 2020 by Kristina Panos 8 Comments

Is there anything LEGO can’t do, aside from turning to a soft gelatin when a human steps on one? The incredible range of piece sizes that make them such versatile building blocks extends their utility far beyond the playroom floor, as [Tolgahan Çoĝulu] demonstrates with his LEGO microtonal guitar.

His LEGO what now? If you’re in the western world, microtones simply refer to those that fall between the 12 semitones-per-octave shackles of the western scale. Microtones are smaller than semitones, so they can bring a richer flavor to music, as evidenced in eastern cultures. In the past, [Tolgahan] has made microtonal guitars with fixed and adjustable frets using standard fret wire. After his young son copied his design in LEGO, he decided to bring it to life.

[Tolgahan] and a friend designed and printed a compatible base plate fingerboard and glued it in place on an old classical guitar. Then he and his son spent hours digging through their hoard to look for 1x1s and other 1x pieces to build up the fingerboard.

Here’s where it gets really interesting — they printed a ton of special 1×1 pieces to build up the moveable frets. Since they’re 1x1s, they can also be used to teach music simply by moving them around to the notes of the scale or song being taught, no matter the hemisphere it comes from. Pluck your way past the break to watch the story play out and hear this LEGO guitar for yourself.

If [Tolgahan] and his son had used machine learning to sort their LEGO, it probably wouldn’t have taken so long to find all those 1x1s.

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Hacked Prosthesis Leads To Mind-Controlled Electronic Music

February 19, 2020 by Dan Maloney 14 Comments

As amazing as prosthetic limbs have become, and as life-changing as they can be for the wearer, they’re still far from perfect. Prosthetic hands, for instance, often lack the precise control needed for fine tasks. That’s a problem for [Bertolt Meyer], an electronic musician with a passion for synthesizers with tiny knobs, a problem he solved by hacking his prosthetic arm to control synthesizers with his mind. (Video, embedded below.)

If that sounds overwrought, it’s not; [Bertolt]’s lower arm prosthesis is electromyographically (EMG) controlled through electrodes placed on the skin of his residual limb. In normal use, he can control the servos inside the hand simply by thinking about moving muscles. After experimenting a bit with an old hand, he discovered that the amplifiers in the prosthesis could produce a proportional control signal based on his inputs, and with a little help from synthesizer manufacturer KOMA Electronik, he came up with a circuit that can replace his hand and generate multiple control voltage channels. Plugged into any of the CV jacks on his Eurorack modular synths, he now has direct mind control of his music.

We have to say this is a pretty slick hack, and hats off to [Bertolt] for being willing to do the experiments and for enlisting the right expertise to get the job done. Interested in the potential for EMG control? Of course there’s a dev board for that, and [Bil Herd]’s EMG signal processing primer should prove helpful as well.

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What Does Your Necklace Say?

February 17, 2020 by Brian McEvoy 2 Comments

If we write about sound reproduction, there is a good chance we found a home-made amplifier or an upcycled speaker system. In this case, you don’t use your ears to appreciate the sound; you use your hands or eyes. [ElatisEagles] converted an amplitude sound graph into a wearable bead. Even without much background it should be immediately recognizable for what it is. Presumably, they converted a sound wave to vectors, then used the “Revolve” function in Rhino, their software of choice. Sometimes this is called a “lathe” function. Resin printers should be able to build these without supports and with incredible fidelity.

Some tattoos put a sound wave on the skin, and use an app to play it back, but if you want to wear a sound bite from your favorite show and not get branded as the “Pickle Rick” gal/guy at the office, maybe swap out the color and sound wave before it goes stale. We would wear a bead that says, “drop a link in our tip line,” but you can probably think of something more clever.

We have other high-tech ornamentation that leverages motion instead of sound, or how about a necklace that listens instead.

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Sequence Your Beats With The Magic Of Magnets

February 15, 2020 by Lewin Day 10 Comments

Typically, when we think of a music sequencer, we envisage LEDs and boards covered in buttons. Of course, there are naturally other ways to build such a device. MesoTune takes a different tack entirely, relying on magnets and rotating mechanisms to get the job done.

MesoTune acts as a MIDI controller, and is designed to be hooked up to a computer or other MIDI synthesizer device. The heart of MesoTune is a set of eight magnet wheels, rotating together on a common shaft. The rotational speed of the shaft, dictated by the requested tempo in beats per minute, is controlled by an Arduino. Each magnet wheel has 16 slots into which the user can place a spherical magnet. Every time a magnet on the wheel passes a hall sensor, it sends a MIDI message to the attached computer which is then responsible for using this to synthesize the relevant sound.

There are other useful features, too. Each of the eight magnet wheels, or channels, gets its own fader, which can be used to control volume or other parameters. There’s also a handy tempo display, and a 16-button touchpad for triggering other events. These additions make it more practical to use in a compositional context, where it’s nice to have extra controls to make changes on the fly.

Made out of 3D printed parts and readily available off the shelf components, it’s a fun alternative sequencer design that we’re sure many makers could whip up in just a weekend. We’d love to see other remixes of the design – if you’ve got one, hit us up at the tipline. We’ve seen other great sequencer builds before, too. Video after the break.