Keytar Made Out Of A Scanner To Make Even the 80s Jealous

Do any of you stay awake at night agonizing over how the keytar could get even cooler? The 80s are over, so we know none of us do. Yet here we are, [James Cochrane] has gone out and turned a HP ScanJet Keytar for no apparent reason other than he thought it’d be cool. Don’t bring the 80’s back [James], the world is still recovering from the last time.

Kidding aside (except for the part of not bringing the 80s back), the keytar build is simple, but pretty cool. [James] took an Arduino, a MIDI interface, and a stepper motor driver and integrated it into some of the scanner’s original features. The travel that used to run the optics back and forth now produce the sound; the case of the scanner provides the resonance. He uses a sensor to detect when he’s at the end of the scanner’s travel and it instantly reverses to avoid collision.

A off-the-shelf MIDI keyboard acts as the input for the instrument. As you can hear in the video after the break; it’s not the worst sounding instrument in this age of digital music. As a bonus, he has an additional tutorial on making any stepper motor a MIDI device at the end of the video.

If you don’t have an HP ScanJet lying around, but you are up to your ears in surplus Commodore 64s, we’ve got another build you should check out.

Three Arduinos, Sixteen Square Waves

[Folkert van Heusden] sent us in his diabolical MIDI device. Ardio is a MIDI synthesizer of sorts, playing up to sixteen channels of square waves, each on its separate Arduino output pin, and mixed down to stereo with a bunch of resistors. It only plays square waves, and they don’t seem to be entirely in tune, but it makes a heck of a racket and makes use of an interesting architecture.

Ardio is made up of three separate el cheapo Arduino Minis, because…why not?! One Arduino handles the incoming MIDI data and sends note requests out to the other modules over I2C. The voice modules receive commands — play this frequency on that pin — and take care of the sound generation.

None of the chips are heavily loaded, and everything seems to run smoothly, despite the amount of data that’s coming in. As evidence, go download [Folkert]’s rendition of Abba’s classic “Chiquitita” in delicious sixteen-voice “harmony”. It’s a fun exercise in using what’s cheap and easy to get something done.

Orbs Light to Billie Jean on this Huge Sequencer

Sequencers allow you to compose a melody just by drawing the notes onto a 2D grid, virtually turning anyone with a moderate feel for pitch and rhythm into an electronic music producer. For  [Yuvi Gerstein’s] large-scale grid MIDI sequencer GRIDI makes music making even more accessible.

Instead of buttons, GRIDI uses balls to set the notes. Once they’re placed in one of the dents in the large board, they will play a note the next time the cursor bar passes by. 256 RGB LEDs in the 16 x 16 ball grid array illuminate the balls in a certain color depending on the instrument assigned to them: Drum sounds are blue, bass is orange and melodies are purple.

Underneath the 2.80 x 1.65 meters (9.2 x 4.5 foot) CNC machined, sanded and color coated surface of the GRIDI, an Arduino Uno controls all the WS2812 LEDs and reads back the switches that are used to detect the balls. A host computer running Max/MSP synthesizes the ensemble. The result is the impressive, interactive, musical art installation you’re about to see in the following video. What better tune to try out first than that of Billie Jean whose lighted sidewalk made such an impression on the original music video.

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Toa Mata Lego Band Actually Rocks

[Opificio Sonico] has been at the Lego-based robot music making business for a while now, and it shows. He’s released four videos on YouTube (all inlined below) and each shows a definite evolution of his style and the Lego ‘bots technical range.

Episode 4, a cover of Daft Punk’s “Alive”, is clearly the most polished. A sliding platform goes enables a Lego “Toa Mata” figure to play the melody on some kind of iDevice (?). The ‘bot playing the DS to hit its one note repeatedly with the stylus, and has an easier job thanks to Daft Punk’s compositional “efficiency”. Episode 3, Depeche Mode’s “Everything Counts” is fantastic, partly because he’s using piezo-miced junk as percussion (as did DM themselves) and partly because of the sliding stylophone. But watch them all.

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iPad Control for Guitar Pedals

[gutbag] is a guitarist. And guitarists are notorious knob-twiddlers: they love their effects pedals. But when your music involves changing settings more than a few times in the middle of a song, it can get distracting. If only there were little robot hands that could turn the knobs (metaphorically, sorry) during the performance…

Tearing into his EHX Pitch Fork pedal, [gutbag] discovered that all of the external knob controls were being read by ADCs on the chip that did all of the processing. He replaced all of the controls with a DAC and some analog switches, coded up some MIDI logic in an ATmega328, and built himself a custom MIDI-controlled guitar pedal. Pretty slick, and he can now control it live with his iPad, or sequence the knobs with the rest of their MIDI system.


This wasn’t [gutbag]’s first foray into pedal automation, however. He’d previously automated a slew of his pedals that were already built to take control-voltage signals. What we like about this hack is the direct substitution of DAC for potentiometers. It’s just hackier. (Oh, and we’re envious of [gutbag]’s lab setup.)

This isn’t the first time we’ve covered [gutbag]’s band, Zaardvark, either. Way back in 2013, we featured an organ-pedal-to-MIDI hack of theirs. Keep on rockin’.

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Digital Wind Chimes

Quality wind chimes are not cheap. No matter how much you spend, though, they generally sound the same year after year. If that bothers you, maybe [sensatroniclab] can help. They’ve posted a simple design for a digital wind chime using the Ototo music generator.

The Ototo is reasonably priced and promises to let you make music from anything (well, anything conductive, anyway).  Because the Ototo handles all the music production, the only real building part of the project is the wind sensors. The sensors are made with conductive fabric with a marble at the end for weight.

In the video below you can see [Matthew Ward] talk about the device and actually play it like you might a harp. This would be a good school project owing to the simplicity of using the Ototo, although [sensatroniclab] is actually working on accessibility music projects.

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Toy Piano Gets Synth Overhaul

The Peanuts cartoon character Schroeder liked to bang out Beethoven a toy piano. Now, thanks to this hack from [Liam Lacey], Schroeder can switch to Skrillex. That’s because [Liam] built a polyphonic synth into a toy piano. It’s an impressive build that retains the look and feel of the piano, right down to a laser-etched top panel with knobs that match the glossy black styling.

The brains of the synthesizer is a Beaglebone Black using the Maximillian synthesis library. To capture the key presses, he used Velostat, a pressure-sensitive material that changes resistance under pressure. This is probably the only toy piano in the world with fully polyphonic velocity and aftertouch. The build also includes MIDI support, with two ports on the back. [Liam]’s build log is full of more details than we can even summarize here.

This beautiful build won [Liam] first place in the Element 14 Music Tech competition, and it is a well-deserved prize for a clean and elegant way to update a vintage piano.

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