Although MIDI was originally designed for 1 MHz computers with 64 kB of RAM, it’s still an industry standard almost 30 years after its introduction. Even for electronic artists armed with a microcontroller, MIDI is old hat if you want to connect a few buttons up to a music workstation. What if you wanted to connect dozens of buttons and knobs to a bunch of MIDI hardware, though? Enter Chomp, the Configurable Hardware Open-source MIDI Platform.

[Max Justicz], an awesome pseudonym if we’ve ever heard one, built a MIDI controller that allows for 48 inputs for buttons, knobs, and any other electrical connection imaginable. The board is powered by an Arduino-fied ATMega328 and connects to your sensors through 2×5 ribbon cables.

If you’ve ever thought about building a monome MIDI controller, [Max Justicz] has started a Kickstarter campaign to put a few hundred Chomps out into the wild. It seems like a great way to build some controllers or simply to send stuff to MaxMSP. Either way, the Chomp is sure to be useful.

At Hack a Day, we don’t throw the term genius around lightly. We’re obligated to bestow that title on [Don Gilmore] for his amazingly simple self-tuning piano. To appreciate [Don]‘s build, you need to realize that just because a piano has 88 keys, that doesn’t mean it has 88 strings. Treble notes have three strings per key while tenor and bass notes have one or two strings each. This usually comes out to more than 200 strings per piano, and [Don] can bring them all up to tune in under a minute.

[Don]‘s system needs to perform two functions. The first one is sustaining the strings so the computer can ‘hear’ the strings. He does this with a magnetic sustainer that is a lot like an E-Bow. To bring the strings up to the right pitch, there are small heaters underneath the pin block. Running a little bit of current through these heaters allows [Don] to decrease the tension of each string and lower the pitch.

This tech reminds us of the Gibson Robot Guitar, a self-tuning guitar that does it’s trick with motors in the tuners. The Gibson didn’t do well on the sales floor, given that everybody and their mom can tune a guitar. Pianos, though, are another story. [Don] is looking for investors to bring his idea to market, and we hope to see it on the floor of a music shop sometime in the future.

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If you’ve never been to a chiptune show – yes, they exist – you’ve noticed the awesome visuals behind the performers that are usually displayed with a glitching NES. If it’s a really good show, that 8-bit visualization will be in sync with the music and may actually serve as a lo-fi spectrum analyzer. [Andy] came up with his own visualization system for a Sega Genesis or Megadrive. With 16 bits behind his build, we’ll say if far surpasses the lowly NES.

For his visualization, [Andy] feeds audio into an ATMega328 and the ever-popular MSGEQ7 seven-band graphic equalizer IC. The output from the EQ goes straight to the second controller input of a Sega Nomad [Andy] had lying around that is running a custom ROM for his show. The ROM is programmed in tandem with the microcontroller project to serve as a spectrum analyzer for his shows.

You can check out [Andy]‘s visualization with the chiptunes of Danimal Cannon after the break. We would prefer a demo featuring An0vA and the code for the microcontroller, but it’s still a very nice demo indeed.

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If you’d like a pseudo-mechanical way of producing a droning synthesizer sound, [gijs] is your man. He made a small synthesizer out of nothing but an old hard drive and a few components.

Whenever a disk platter is spun manually, the spindle motor inside the drive produces a few out of phase sine waves on its connections. [gijs]‘ synthesizer compares and amplifies these sine waves and sends them out to a speaker. The result is a strange droning chiptune-esque arpeggio.

The circuit for the build is soldered directly to the hard drive enclosure Manhattan style. Because the output of the spindle motor produces out of phase sine waves, [gijs] thought it would be a good idea if he could capitalize on some phase interference to alter the timbre of his synth. The entire build is mounted to a wall with hinges to one side so the speaker can be moved around. It isn’t much of a change, but we can here some wave forms cancelling each other out.

Check out the video of the build after the break. There’s also a few audio samples available on the project page.

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For all the wonder of dulcet tones coming from a century-old music box, we’ve got to admit that [Markus]‘ wavetable synthesis build is still pretty impressive. Of course, the Internet cred gained by doing a demo of Still Alive helps too.

Wavetable synthesis stores a one cycle long waveform in RAM that can be played on a loop at varying frequencies. This technique has been around since the late 70s and can be found in a lot of the classic synths of the 80s and serves as the basis for Atari MOD music and the Game Boy chiptunes produced with Little Sound DJ

[Markus] found a pair of battery-powered laptop speakers and decided a music box would be a wonderful project. Inspired by [ChaN]‘s ATtiny wavetable synthesizer, [Markus] decided to up the ante and use a PIC32 microcontroller to make the programming a little more digestable. The entire project (with an awesome dead bug soldering job) is nearly as large as the PIC itself.

[Markus] threw up the source code along with some Python scripts to convert waveforms and MIDI files into something the chip can understand. Before you check that out, be sure to look at the Still Alive demo.

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[Jonathan Thomson] was ruminating on EL wire displays and decided that most he has seen are boring, static fixtures or installations that simply flash EL wire on and off at a fixed rate. He thought that EL wire has far more potential than that, and set off to build something more exciting. Using a graphic equalizer T-shirt, with which we’re sure you are familiar, he put together a slick, sound-reactive EL wire display.

He started off by removing the EL panel and inverter from the aforementioned T-shirt, separating the display into two pieces. He set aside the panel and focused on wiring up the inverter’s ribbon cable to a set of EL wire strands he picked up for the project. Once he had everything hooked up, he put a design together on a cardboard box, which he intended to use for wrapping Christmas presents. With the holiday behind him, [Jonathan] broke down his original display and constructed another to offer up some fun birthday wishes.

While the EL inverter was originally built to display sounds detected by an onboard mic, [Jonathan] added a 3.5” stereo jack to his so that he can feed audio directly into the display using an MP3 player.

Continue reading to see the EL display in action, and be sure to check out his writeup if you are looking to spice up your gift giving this year.

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Weekly Hack a Day feature [Dino] is back again, this time with his very own guitar pedal. It’s modeled on a three-transistor Fuzz Face clone and sounds very good in our humble opinion.

Fuzz pedals were some of the first guitar pedals on the market, and for good reason. Their easy construction and simple theory of operation (just amplify sound until the transistor saturates) made them an economical and available pedal for the legends of rock in the 60s. [Dino]‘s build follows this tradition of simplicity with a common 2N3904 transistor and a pair of BC547 Silicon transistors. We’re guessing [Dino] couldn’t find any cred-worthy and mojo-giving Germanium transistors, but the result sounds just as good as we could imagine.

To test out his pedal, [Dino] hooked up a [Jack White] style single string lap steel and turned everything up to 12*. The result is rock. Check out the build vid after the break.

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[Ian Cole’s] son is learning to play the drums on an electronic drum set, and he wanted a way to continue practicing during his frequent visits to his grandparents’ house. [Ian] had picked up a Spikenzielabs “Drum Kit Kit All-Inclusive” (DKKAI) earlier this summer, and set out to build an easily transportable drum set.

The DKKAI comes with an ATmega168-based board and a set of piezos that can be used to register hits. It was up to [Ian] to provide the rest of the kit, so he set off to IKEA in search of cheap, durable drum heads. He returned with a handful of 1/2 Liter plastic bowls, which he mounted on a PVC pipe drum stand.

The piezos were mounted on thin aluminum discs, which were in turn glued to the back side of the bowl lids. The piezos were wired to the DKKAI kit via the PVC tubing, with the signals ultimately fed into an iPad running Garage Band. [Ian] says that his portable drum set works quite well, and although there are some things that require changing, his son is very happy with his new practice set.

Check out the video below to see the portable drum kit in action.

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