Fabric(ated) Drum Machine

January 7, 2020 by Brian McEvoy 3 Comments

Some folks bring out an heirloom table runner when they have company, but what if you sewed your own and made it musical? We’d never put it away! [kAi CHENG] has an Instructable about how to recreate his melodic material, and there is a link to his website, which describes his design process, not just the finished product. We have a video below showing a jam session where he exercises a basic function set.

GarageBand is his DAW of choice, which receives translated MIDI from a Lilypad. If you don’t have a Lilypad, any Arduino based on the ATmega328P chip should work seamlessly. Testing shows that conductive threads in the soft circuit results in an occasional short circuit, but copper tape makes a good conductor at the intersections. Wide metallic strips make for tolerant landing pads beneath modular potentiometers fitted with inviting foam knobs. Each twist controls a loop in GarageBand, and there is a pressure-sensitive pad to change the soundset. Of course, since this is all over MIDI, you can customize to your heart’s content.

MIDI drums come in all shapes and sizes, from a familiar game controller to hand rakes.

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The Hacker History Of Music Technologies

January 6, 2020 by Lewin Day 7 Comments

Music throughout history has been inspired and changed by hackers and makers, and never moreso than in the 20th century. Helen Leigh is one such hacker, who brought a talk to Supercon to give us a crash course in the history of recording, electronics and music, and what the maker movement is doing in the music world today.

The tape recorder was an invention that kicked off a golden period of exploration in sound. Beginning in World War II, the Nazi propaganda machine cut and spliced recorded materials and disseminated them across broadcasting stations in Europe. To the astonishment of the Allies, certain German officials appeared to be making broadcasts from different studios at the same time, due to the high quality of the recording hardware. After the war, this technology was discovered by a group of Parisian recording artists who began to experiment with an art that became known as musique concrète, using tape hardware in weird and wonderful ways to create new sounds heretofore unheard in nature.

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Turning Sounds From A Flute Into Sheet Music

December 29, 2019 by Sharon Lin 12 Comments

Composing music can be quite difficult – after all, you have to keep in mind all of the elements of musical theory, from time signature and key signature to the correct length for all of the notes. A team of students from Cornell University’s Designing with Microcontrollers class developed a solution for this problem by transcribing sounds from a flute into sheet music.

The project doesn’t simply detect the notes played – it is able to convert the raw audio into a standardized music score complete with accurate note timings and beats per minute. Before transcribing the music, some audio processing was necessary. The team chose to use a Sallen-Key filter to amplify the raw audio input due to its complex conjugate poles. They then used a fast Fourier Transform (FFT) to determine the frequency for the input note, converting the signal from the time domain to the frequency domain.

The algorithm samples the data to generate an input signal, using the ADC on the microcontroller to receive input from the microphone. It takes the real and imaginary components of the sampled signals and outputs a pair of real and imaginary amplitude components corresponding to the sampled frequency, evenly spaced from 0 to the Nyquist rate (half the sampling rate). The spacing of these bins and the bin with the largest amplitude are used to convert the signal back to a real frequency and a MIDI note.

The system uses a PIC32 for the logic. The circuitry for the microphone amplification uses a non-inverting op-amp with a gain of 50 to increase the microphone output signal amplitude from 15 mV to 750 mV to use by the microcontroller’s ADC. The signal is then sent to the anti-aliasing Sallen-Key filter, with a pole at 2.5 kHz and a Q of 1. The frequency was chosen since the FFT samples at 8 kHz and the frequency corresponds to a note out of the range of a flute. As for the filters, only the low pass filter was implemented in hardware. While a bandpass filter could have been implemented in hardware, the team decided on a cleaner software approach.

The project is well-documented on the team’s project page, and it’s certainly worth checking out for more detailed discussions on the keypad controls and the software side of the audio processing. If you want to learn more about the FFT, check out this 2016 Hackaday Prize entry for an FFT spectrum analyezer.

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Need Hackable Melodies? Here’s The TETRIS Theme And More

December 25, 2019 by Donald Papp 3 Comments

[Robson Couto] started to get interested in musical projects and as a side effect created downloadable code with simple notation for a good variety of themes, songs, and melodies. They are all for the Arduino and use only the built-in tone() function, but don’t let that distract you. If you look past that, you’ll see that each sketch is a melody that consists of single notes and durations; easily adapted to other purposes or simply used as-is. After all, [Robson] wanted the source of each tune to be easily understood, easily modified, and to have no external dependencies.

All that may sound a bit like MIDI, but MIDI has much more in common with hardware events than music notation because it includes (among other things) note starts and note ends as separate elements. Converting MIDI into a more usable format was a big part of a project that fed Bach music to a neural network and got surprisingly good results.

When doing music projects, sometimes having a recognizable melody represented very simply as notes and durations with only one note at a time can be an awfully handy resource, and you can find them on GitHub. There’s a brief video of the Tetris theme (actual name: Korobeiniki) being played after the break.

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Bottle Organ Breakdown

December 14, 2019 by Brian McEvoy 8 Comments

A keen-eyed commenter pointed us to a homemade bottle organ that plays like a piano. The complexity gets turned up with foot-powered bellows and custom keys, but the magic of [Mike] and [Simon Haisell]’s garage-built instrument is not lost in the slightest. We also have the video below the break and there is a bottle organ performance by [Coyote Merlot].

The working concepts are explained well in the video, and that starts with the bellows. In the first few seconds of the video, we see an organist swaying as he plays, and it would be accurate to say the music moves him. The wobbling is to pedal a couple of levers that squeeze a pair of air sacs and slide under wheels that look like a hardware store purchase. The spring-return mechanism is a repurposed bungee cord and you know we dig that kind of resourcefulness. Each bellow valve is made with traditional leather flaps of the type that predate bungee cords and camera phones. These air pumps inflate a big reservoir in the back that provides continuous pressure to a manifold where each of the thirty-six keys control a valve responsible for one bottle. The pair built every wooden part we mentioned with the explicit purpose of creating this organ.

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Sara Adkins Is Jamming Out With Machines

December 4, 2019 by Kristina Panos 1 Comment

Asking machines to make music by themselves is kind of a strange notion. They’re machines, after all. They don’t feel happy or hurt, and as far as we know, they don’t long for the affections of other machines. Humans like to think of music as being a strictly human thing, a passionate undertaking so nuanced and emotion-based that a machine could never begin to understand the feeling that goes into the process of making music, or even the simple enjoyment of it.

The idea of humans and machines having a jam session together is even stranger. But oddly enough, the principles of the jam session may be exactly what machines need to begin to understand musical expression. As Sara Adkins explains in her enlightening 2019 Hackaday Superconference talk, Creating with the Machine, humans and machines have a lot to learn from each other.

To a human musician, a machine’s speed and accuracy are enviable. So is its ability to make instant transitions between notes and chords. Humans are slow to learn these transitions and have to practice going back and forth repeatedly to build muscle memory. If the machine were capable, it would likely envy the human in terms of passionate performance and musical expression.

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Electric Dreams Help Cows Survive The Desert Of The Real

December 3, 2019 by Tom Nardi 64 Comments

Pictures of a cow wearing a pair of comically oversized virtual reality goggles recently spread like wildfire over social media, and even the major news outlets eventually picked it up. Why not? Nobody wants to read about geopolitical turmoil over the holidays, and this story was precisely the sort of lighthearted “news” people would, if you can forgive the pun, gobble up.

But since you’re reading Hackaday, these images probably left you with more questions than answers. Who made the hardware, what software is it running, and of course, why does a cow need VR? Unfortunately, the answers to the more technical questions aren’t exactly forthcoming. Even tracking the story back to the official press release from the Ministry of Agriculture and Food of the Moscow Region doesn’t tell us much more than we can gather from the image itself.

But it does at least explain why somebody went through the trouble of making a custom bovine VR rig: calm cows produce more milk. These VR goggles, should they pass their testing and actually be adopted by the Russian dairy industry, will be the newest addition to a list of cow-calming hardware devices that farmers have been using for decades to get the most out of their herds.

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