Musical Hacks

1490 Articles

MIDI-Gurdy, MIDI-Gurdy, MIDI-Gurdy Man

July 4, 2019 by 19 Comments

The hurdy gurdy is the perfect musical instrument. It’s an instrument with a crank, and a mechanical wonderment of drone strings and weird chromatic keyboards. No other musical instrument combines the sweet drone of bagpipes with the aural experience of an eight-year-old attempting to play Hot Cross Buns on a poorly tuned violin.

Now, the hurdy gurdy is going digital. The Digi-Gurdy is [XenonJohn]’s entry into this year’s Hackaday Prize, and it’s exactly what it says on the tin: it’s a musical instrument that drones on and on, with keys plunking out a melody.

If you’re not familiar with a hurdy gurdy, this video is a varily good introduction. It’s a box with somewhere between four and six strings mounted on the outside. The strings vibrate by means of a wooden wheel powered by a crank. There’s a keyboard of sorts along the body of the instrument that ‘fret’ a single string providing the melody; all the other strings are drone strings that sound continuously. I think it was in, like, a Led Zeppelin video, man.

While it’s a slightly complicated build to make an analog hurdy gurdy, delving into the digital domain is easy: [XenonJohn] is building a hurdy gurdy that simply outputs MIDI commands with some buttons and a Teensy 3.6 microcontroller. The parts are 3D printed, and since this hurdy gurdy is completely digital, you can change the tuning of the drone strings without actually tuning them. Awesome.

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This MDF Sound Bar Sounds Great

July 3, 2019 by 12 Comments

Everyone should build a speaker cabinet at least once in their life, if only so they can realize how much thought goes into building a simple box. [John] of ibuildit.ca wanted a sound bar for his home theater setup, and that means building a sound bar. The result is beautiful, and a demonstration of how much you can do with just a router and a table saw.

[John] built this sound bar almost entirely out of MDF, which isn’t the best material but it works well enough for a speaker cab that’s meant to be mounted to a wall. The sides were constructed first, with a rabbet holding the front and back on. Both the woofer and tweeter are inset into the front, and a standard piece of plumbing pipe serves as the bass port. Slap a round over bit into the router and do some light sanding, and everything looks great with a coat of black paint.

As with any speaker enclosure, the design is effectively parametric, designed entirely around the drivers being used. In this case, [John] is using a spreadsheet named ‘Unibox’ that gives you all the formulas and graphs for designing a speaker enclosure.

With the box built and the speakers installed, the only matter left were a few aesthetic choices. [John] went with a standard black finish with a very nice wooden grille held onto the front with magnets. It’s a design that pops, but the true test of a speaker is how it sounds. That’s a bit hard to convey over the Internet, but [John] included a few sound samples at the end of the build video, available below.

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A Baby Named DJ

June 19, 2019 by 8 Comments

Some of us are guilty of picking up questionable hardware from garage sales, fleamarkets, and well-meaning relatives. There is a balance between turning down a good investment and hoarding, and if we figure out how to tell the difference you will be the first to know. [Clem Mayer] may start on the side of unwise acquisition, but he pushes a broken fetal detector into the realm of awesome by converting it to an analog synthesizer, born to headline at an Eastern European dance party.

He starts with a basic teardown, and we get to see how old hardware was serviceable with only two standard screws. It is a good thing too, because the nickel-cadmium batteries are older than some of you and they are in need of replacement. New nickel-metal hydride batteries got it up and running but [Clem] does not have a baby bump so its functionality turned to Pink Floyd era synthesizer circuit bending. Circuit bending involves modifying a circuit for sound it was not intended to make.

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DIY Raspberry Pi Multi FX Stomp Box

June 17, 2019 by 3 Comments

From building your own analog effects pedal to processing audio through micro controllers, a lot of musicians love building their own boxes of sound modification. In his entry for the 2019 Hackaday Prize, [Craig Hissett] has a project to build an all-in-one multi-effects stomp box.

At the center of the box is a Raspberry Pi with an AudioInjector stereo sound card.  The card takes care of stereo in and out, and passing the signal to the Pi. The software is Modep, an open source audio processor that allows the setup of a chain of digital effects plugins to be run on the Pi. After finding some foot switches, [Craig] connected them to an Arduino Pro Micro which he set up as a MIDI device that sends MIDI messages to the Modep software running on the Pi.

There are still a few steps to go, but [Craig] has the basic layout covered. Next up is wiring it up and building a proper case for it, as well as working on latency. A few years ago, another multi-effects stomp box was featured in the Hackaday Prize, and last year, this multi-effects controller was featured.

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Exquisite Craftsmanship Elevate Vic’s Creations Above The Rest

June 16, 2019 by 13 Comments

This booth was easy to miss at Maker Faire Bay Area 2019 amidst tall professional conference signage erected by adjacent exhibitors. It showcased the work of [Dr. Victor Chaney] who enjoys his day job as a dentist and thus feels no desire to commercialize his inventions — he’s building fun projects for the sake of personal enjoyment which he simply calls Vic’s Creations. Each project is built to his own standards, which are evidently quite high judging by the perfect glossy finish on every custom wood enclosure.

Some of these creations were aligned with his musical interests. The Backpacking Banjo was built around a (well cleaned) cat food can to satisfy the desire for a lightweight instrument he can take camping. His Musical Laser Rainbow Machine (fully documented in Nuts & Volts) was created so little bands formed by independent artists like himself can have a visual light show to go with their live performances. The Music Kaleidoscope is another execution along similar lines, with an LED array whose colors are dictated by music. Venturing outside the world of music, we see a magnetically levitated Castle In The Clouds which also receives power wirelessly to illuminate LEDs

The largest and most complex work on display is an epic electromechanical masterpiece. Par One is a rolling ball sculpture featuring the most convoluted golf course ever. Several more rolling ball sculptures (also called marble machines or marble runs) are on display at Dr. Chaney’s office which must make it the coolest dentist’s lobby ever. The lifelike motions he was able to get from the automatons he built into the sculpture are breathtaking, as you can see below.

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Magic Record Stand Can Play Your Records For You

June 12, 2019 by 21 Comments

Vinyl remains a popular format, despite taking a huge hit in popularity for a couple decades while CDs ruled the roost. It has a charm that keeps it relevant, and likely will continue to do so until everyone who grew up with a record player dies out. In the meantime, [sp_cecamp] has come up with a great way to experience your collection, with the magic of modern technology. It goes by the name of Plynth.

Fundamentally, it’s a small record stand with an excellent party trick. The prototype consists of a 3D-printed body, which holds a record sleeve at an attractive angle for display. A camera built into the base then images the artwork. The first image taken is run through the Google Vision API, and further images are then run through OpenCV to identify the record. This data is then passed to the Spotify API to play the track. The whole process takes a couple of seconds, and the music is then pumped out of whatever streaming device is connected to the rig.

It’s a fun way to play your old records, and would be a welcome change to those tired of screaming at Siri to play Weezer (Blue Album), not Weezer (Green Album). For those interested, [sp_cecamp] has thrown up a site to gauge interest in the project, and may make a limited production run in future.

Of course, you could instead just go about building your own turntable. To each their own!

Mechanical Tremolo Does Things The Old-School Way

June 12, 2019 by 21 Comments

The word “tremolo” has a wide variety of meanings in the musical lexicon. A tremolo effect, in the guitar community at least, refers to a periodic variation in amplitude. This is often achieved with solid state electronics, but also recalls the sounds created by Hammond organs of years past with their rotating Leslie speakers. [HackaweekTV] decided to do things the old fashioned way, building a mechanical tremolo effect of his own (Youtube link, embedded below).

Electronically, the signal is simply passed through a linear audio potentiometer. The effect is generated by rapidly cycling this potentiometer up and down. The motion is achieved through a geared motor salvaged from a Roomba, which turns a cam. A sprung follower sits on top of the cam, and is attached to the potentiometer.

There were some challenges in development. Rigidity of the frame was an issue, and the follower had issues with snagging on the cam. However, with some careful iteration they were able to get everything up and running. The final project sounds great, and with the amplifier turned up, there’s no need to worry about the sound of the moving parts.

Naturally, you can always build a tremolo with a 555 instead. Video after the break.

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