Musical Hacks

1374 Articles

[Joe Grand’s] Toothbrush Plays Music That Doesn’t Suck

March 27, 2017 by 40 Comments

It’s not too exciting that [Joe Grand] has a toothbrush that plays music inside your head. That’s actually a trick that the manufacturer pulled off. It’s that [Joe] gave his toothbrush an SD card slot for music that doesn’t suck.

The victim donor hardware for this project is a toothbrush meant for kids called Tooth Tunes. They’ve been around for years, but unless you’re a kid (or a parent of one) you’ve never heard of them. That’s because they generally play the saccharine sounds of Hannah Montana and the Jonas Brothers which make adults choose cavities over dental health. However, we’re inclined to brush the enamel right off of our teeth if we can listen to The Amp Hour, Embedded FM, or the Spark Gap while doing so. Yes, we’re advocating for a bone-conducting, podcasting toothbrush.

[Joe’s] hack starts by cracking open the neck of the brush to cut the wires going to a transducer behind the brushes (his first attempt is ugly but the final process is clean and minimal). This allows him to pull out the guts from the sealed battery compartment in the handle. In true [Grand] fashion he rolled a replacement PCB that fits in the original footprint, adding an SD card and replacing the original microcontroller with an ATtiny85. He goes the extra mile of making this hack a polished work by also designing in an On/Off controller (MAX16054) which delivers the tiny standby current needed to prevent the batteries from going flat in the medicine cabinet.

Check out his video showcasing the hack below. You don’t get an audio demo because you have to press the thing against the bones in your skull to hear it. The OEM meant for this to press against your teeth, but now we want to play with them for our own hacks. Baseball cap headphones via bone conduction? Maybe.

Update: [Joe] wrote in to tell us he published a demonstration of the audio. It uses a metal box as a sounding chamber in place of the bones in our head.

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How To Play The Bass With Marbles

March 26, 2017 by 9 Comments

Stringed instruments make noise from the vibrations of tuned strings, using acoustic or electronic means to amplify those vibrations to the point where they’re loud enough to hear. The strings are triggered in a variety of ways – piano strings are hit with hammers, guitar strings are plucked, while violin strings are bowed. Meanwhile, [Martin] from the band [Wintergatan] is using marbles to play a bass guitar.

[Martin] starts out with a basic setup. The bass guitar is placed on the workbench, while a piece of wood is taped to a tripod. The wood has a hole drilled through it, and marbles are dropped through the aperture in an attempt to get them to land on the string. Plastic containers are used to easily alter the angle the bass guitar sits at, relative to the bench, while an acrylic guide sits around the string to try to guide the marbles in the desired direction. These guides are important to make sure the marbles hit the top of the string, and bounce cleanly in the desired direction afterwards.

The initial setup is too inconsistent, so [Martin] places a notch in the wood and builds a lever system to hold the marbles and then release them in a controlled manner. [Martin] then checks that the system works by analysing footage of the marble drop with slow motion video.

The video covers the CAD design of an eight-slot guide so the four strings of the bass can be played more rapidly than in their previous build. Two guides per string allow each string to play two notes in quick succession without having to worry about marble collisions from playing too quickly.

It’s a great build, and we’ve seen [Wintergatan]’s work before – namely, the incredible build that was the original Marble Machine.

Thanks to [Tim Trzepacz] for the tip!

MIDI Drawings Paint With Piano Keyboards

March 25, 2017 by 9 Comments

Musician [Mari Lesteberg] is making music that paints pictures. Or maybe she’s making pictures that paint music. It’s complicated. Check out the video (embedded below) and you’ll see what we mean. The result is half Chinese scroll painting, and half musical score, and they go great together.

Lots of MIDI recorders/players use the piano roll as a model for input — time scrolls off to the side, and a few illuminated pixels represent a note played. She’s using the pixels to paint pictures as well: waves on a cartoon river make an up-and-down arpeggio. That’s a (musical) hack. And she’s not the only person making MIDI drawings. You’ll find a lot more on reddit.

Of course, one could do the same thing with silent pixels — just set a note to play with a volume of zero — but that’s cheating and no fun at all. As far as we can tell, you can hear every note that’s part of the scrolling image. The same can not be said for music of the black MIDI variety, which aims to pack as many notes into a short period of time as possible. To our ears, it’s not as beautiful, but there’s no accounting for taste.

It’s amazing what variations we’re seeing in the last few years on the ancient piano roll technology. Of course, since piano rolls are essentially punch-cards for musical instruments, we shouldn’t be too surprised that this is all possible. Indeed, we’re a little bit surprised that new artistic possibilities are still around. Has anyone seen punch-card drawings that are executable code? Or physical piano rolls with playable images embedded in them?

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Teensy Laser Harp Has Big Sound

March 20, 2017 by 11 Comments

[Johan] has slipped down the rabbit hole of making musical instruments. His poison? Laser harp MIDI controllers. Having never made one before, he thought he would start small and then iterate using what he learned. Fortunately for us, [Johan] documented the process over on .io, essentially creating a step-by-step guide for building a simple but powerful 16-note laser harp.

Laser Harp I is built around a Teensy 3.2 and, of course, lasers pointed at LDRs. [Johan] used fairly low-power laser modules, which are slightly less blinding if you accidentally look at them for a second, but should still be taken seriously. He added four potentiometers to control the sensitivity, scale, octave, and the transposition. The sensitivity pot essentially accounts for the ambient light in the room. Although it only has 16 notes, Laser Harp I is ready to rock with over 30 different scales to choose from. Check out the brief demo that [Johan] put up on his Instagram.

If you try to build your own laser harp and get lost trying to follow [Johan]’s instructions, don’t worry. His well-commented code and lovely schematic will undoubtedly save you. Then you can move on to open-beam designs.

Zelda And The Ocarina Of Things

March 20, 2017 by 21 Comments

Voice recognition is this year’s model for home automation, but aside from feeling like you’re onboard the Aries 1b arguing with HAL 9000, it just doesn’t do it for our geeky selves. So what’s even geekier? How about carrying around an ocarina in your pocket so that you can get a Raspberry Pi to unlock the door for you? (YouTube video, embedded below.) Yeah, that’ll do.

[Sufficiently Advanced]’s video gets us 90% of the way toward replicating this build. There’s a tube with a microphone and a Raspberry Pi inside. There are a bunch of ESP8266-powered gadgets scattered around the house that take care of such things as turning on and off the heater, watering plants, and even pressing a (spare) car remote with a servo.

We’d love to know what pitch- or song-recognition software the Raspberry Pi is running. We’ve wanted to implement a whistling-based home automation interface since seeing the whistled. We can hold a tune just fine, but we don’t always start out on the same exact pitch, which is a degree of freedom that [Sufficiently Advanced]’s system doesn’t have to worry about, assuming it only responds to one ocarina.

If you’re questioning the security of locking and unlocking your actual apartment by playing “Zelda’s Lullaby” from outside your window, you either overestimate the common thief or you just don’t get the joke. The use case of calling (and hopefully finding) a cell phone is reason enough for us to carry a bulky ocarina around everywhere we go!

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Dumpster Dive Speaker Results In Tube Amplifier

March 18, 2017 by 14 Comments

[Michael Wiebusch] found the leftovers of a wrecked vintage tube radio in a pile of electronics junk. Unfortunately, he could not recover any vacuum tubes in it. And to his dismay, it didn’t even have the output transformer, which he figured would have been useful in a guitar amplifier project. The output transformer is not easy to come by nowadays, so he was hoping to at least score that item for his future build. All he could dig out from his dumpster find was a pair of speakers and he ended up building nice Output-Transformer-Less Tube Guitar Amplifier around them.

Valve output stages are generally high-impedance which means they cannot be directly interfaced to low impedance speakers. An impedance matching output transformer is thus used to interface the two. Back in the day when valves were still the mainstay of audio electronics, many cheap amplifier designs would skimp on the output transformer to save cost, and instead use high impedance speakers connected directly to the amplifier output.

[Michael] found a nice reference design of an OTL amplifier for a 620 ohm single speaker. He decided to use the same design but because these speakers were about 300 ohm each, he would have to wire his two speakers in series. At this point, he decided to make his build useful as a proper guitar amplifier by adding a preamplifier stage replicated from another design that he came across. A regular halogen lamp 12V transformer takes care of the heater power supply for all the tubes, and a second, smaller 12V transformer is wired backwards to provide the 300V needed for the plate supply.

The final result is pretty satisfactory, considering that it all started with just a pair of junked speakers. Check out the result in the video after the break.

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Neural Network Composes Music; Says “I’ll Be Bach”

March 17, 2017 by 36 Comments

[carykh] took a dive into neural networks, training a computer to replicate Baroque music. The results are as interesting as the process he used. Instead of feeding Shakespeare (for example) to a neural network and marveling at how Shakespeare-y the text output looks, the process converts Bach’s music into a text format and feeds that to the neural network. There is one character for each key on the piano, making for an 88 character alphabet used during the training. The neural net then runs wild and the results are turned back to audio to see (or hear as it were) how much the output sounds like Bach.

The video embedded below starts with a bit of a skit but hang in there because once you hit the 90 second mark things get interesting. Those lacking patience can just skip to the demo; hear original Bach followed by early results (4:14) and compare to the results of a full day of training (11:36) on Bach with some Mozart mixed in for variety. For a system completely ignorant of any bigger-picture concepts such as melody, the results are not only recognizable as music but can even be pleasant to listen to.

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