Getting MIDI Under Control

When [Mr. Sobolak] started his DIY Midi Fighter he already had experience with the MIDI protocol, and because it is only natural once you have mastered something to expand on the success and build something more impressive, more useful, and more button-y. He is far from rare in this regard. More buttons mean more than extra mounting holes, for example an Arduino’s I/O will fill up quickly as potentiometers hog precious analog inputs and button arrays take digital ones. Multiplexing came to the rescue, a logic-based way to monitor or control more devices, in contrast to the serial protocols used by an IO expander.

Multiplexing was not in [Mr. Sobolak]’s repertoire, but it was a fitting time to learn and who doesn’t love acquiring a new skill by improving upon a past project? All the buttons were easy enough to mount but keeping the wires tidy was not in the scope of this project, so if you have a weak stomach when it comes to a “bird’s nest” on the underside you may want to look away and think of something neat. Regardless of how well-groomed the wires are, the system works and you can listen to a demo after the break. Perhaps the tangle of copper beneath serves a purpose as it buoys the board up in lieu of an enclosure.

We are looking forward to the exciting new versions where more solutions are exercised, but sometimes, you just have to tackle a problem with the tools you have, like when the code won’t compile with the MIDI and NeoPixel libraries together so he adds an Uno to take care of the LEDs. Is it the most elegant? No. Did it get the job done? Yes, and if you don’t flip over the board, you would not even know.

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Hiding Data In Music Might Be The Key To Ditching Coffee Shop WiFi Passwords

In a move guaranteed to send audiophiles recoiling back into their sonically pristine caves, two doctoral students at ETH Zurich have come up with an interesting way to embed information into music. What sounds crazy about this is that they’re hiding data firmly in the audible spectrum from 9.8 kHz to 10 kHz. The question is, does it actually sound crazy? Not to our ears, playback remains surprisingly ok.

You can listen to a clip with and without the data on ETH’s site and see for yourself. As a brief example, here’s twelve seconds of the audio presenting two versions of the same clip. The first riff has no data, and the second riff has the encoded data.

You can probably convince yourself that there’s a difference, but it’s negligible. Even if we use a janky bandpass filter over the 8 kHz -10 kHz range to make the differences stand out, it’s not easy to differentiate what you’re hearing:

After many years of performing live music and dabbling in the recording studio, I’d describe the data-encoded clip as having a tinny feedback or a weird reverb effect. However, you wouldn’t notice this in a track playing on the grocery store’s speaker. Continue reading “Hiding Data In Music Might Be The Key To Ditching Coffee Shop WiFi Passwords”

The Theremin Gets A Voice

Every once in a while, we come across a project that adds a ridiculously good twist on an existing design. This is exactly what [Xiao Xiao] and the team at LAM research group at the Institut d’Alembert in Paris have done. Their project T-VOKS is a singing and Speaking Theremin that is sure to drive everyone in the office crazy. (YouTube link, embedded below for your viewing pleasure.)

For the uninitiated, the Theremin is an electronic music instrument that does not require physical contact. Instead, it uses two antennas to sense the distance of the operators hands and uses that to modulate the pitch and volume of the output audio. From music concerts to movie background music to even scaring the neighbours, this instrument can do it all.

T-VOKS is a different take on the instrument, and it interfaces with a voice synthesizer to sing. There is an additional sensor that is used for the syllable sequencing, and the video below shows the gadget in operation. The icing on the cake is the instrument playing, or should that be singing in an actual concert. There is also a research paper detailing the operation on Dropbox[PDF] if you need the nitty-gritty.

We wonder how a TTS engine would work with this idea and hope to see some more projects like it in the future. Fore those looking to get started, have a look at the build guide for a DIY theremin.

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Hacking The Pocket Operator

The number of easily usable and programmable microcontrollers is small, so when selecting one for a project there are only a handful of very popular, well documented chips that most of us reach for. The same can be said for most small companies selling electronics as well, so if you reach for a consumer device that is powered by a microcontroller it’s likely to have one of these few in it. As a result, a lot of these off-the-shelf devices are easy to hack, reprogram, or otherwise improve, such as the Robot Pocket Operator.

The Pocket Operator is a handheld, fully-featured synthesizer complete with internal speaker. It runs on a Cortex M3, a very popular ARM processor which has been widely used for many different applications, and features everything you would need for a synthesizer in one tiny package, including a built-in speaker. It also supports a robust 24-bit DAC/ADC and all the knobs and buttons you would need. And now, thanks to [Frank Buss] there is a detailed teardown on exactly how this device operates.

Some of the highlights from the teardown include detailed drawings of how the display operates, all of the commands for controlling the device, and even an interesting note about how the system clock operates even when the device has been powered off for a substantial amount of time. For a pocket synthesizer this has a lot to offer, even if you plan on using it as something else entirely thanks to the versatility of the Cortex M3.

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A Baby Named DJ

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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Hack My Wired Heart

Liner notes? Passé. In Berlin, the release of a special edition synth-wave record came with an accompanying experimental synthesizer called Wired Heart.

At the core of this adorable heart-shaped synth, designed by music technology enthusiast [tobi tubbutec], is the classic 74HCT14 chip with six Schmitt trigger oscillators. The bright red PCB has eight gold touch and humidity sensing pads that activate and modulate these oscillators. As well as changing the sounds by playing with pressure and conductive liquids you can use the six sets of header pins on board to plug in your own components for noisy experimentation. Wired Heart ships with LEDs, photoresistors and a potentiometer, but we’ve also plugged our own DIY fabric pressure sensors into this synth to make some excellent electronic sounds.

In the post linked above, [tobi tubbutec] walks us through a number of the circuit design decisions he made while prototyping his “cardiotronic human-touch hexoscillatric stereo esoteric snythespacer”. We enjoyed his creative and sometimes unconventional designs, from his inclusion of non-functioning traces for aesthetic reasons to his chosen method of hard syncing — injecting a small pulse of one oscillator into the other. If you want to examine his layout in more detail, [tobi tubbutec] has helpfully included the KiCad schematic file in his write up.

This adorable, hackable synth caught our eye at this year’s SuperBooth — an annual indie electronic music conference in Berlin that’s well worth checking out if odd noises and handmade electronics are your thing —  but it’s recently been listed on Tindie too. To listen to the upbeat synth-wave record Wired Heart originally shipped with, visit the artist Hyboid’s bandcamp.

If you’re interested in experimental musical instruments and synthy chip tune you’ll also love [jarek319]’s Sega Genesis synthesiser.

Check out a demo of the Wired Heart synth in the video after the break.

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Please Meet ‘Capability Inquiry’, Part Of The MIDI 2.0 Standard

It may have passed you by in the news, but the MIDI Manufacturers Association (MMA) has recently unveiled more details about the upcoming MIDI 2.0 standard. Previously we covered the prototyping phase start of this new standard. The original Musical Instrument Digital Interface standard was revealed all the way back in August of 1983, as a cooperation between companies including Moog Music, Roland, Yamaha, Korg, Kawai and others. It was the first universal interface that allowed one to connect and control all kinds of musical instruments.

Over the years, MIDI has seen use with the composing of music, allowing instruments to be controlled by a computer system and to easily share compositions between composers. Before MIDI such kind of control was limited to a number of proprietary interfaces, with limited functionality.

The MMA lists the key features of MIDI 2.0 as: Bidirectional, Backwards Compatible, and the enhancing of MIDI 1.0 where possible. Using a new technology called MIDI Capability Inquiry (MIDI-CI), a MIDI 2.0 device can exchange feature profiles and more with other 2.0 devices. 1.0 is the fallback if MIDI-CI finds no new functionality. MIDI-CI-based configuration can allow 2.0 devices to automatically configure themselves for their environment.

Suffice it to say, MIDI 2.0 is a far cry from the original MIDI standard. By transforming MIDI into a more versatile, bidirectional protocol, it opens new ways in which it can be used to tie musical devices and related together. It opens the possibility of even more creative hacks, many of which were featured on Hackaday already. What will you make with MIDI 2.0?

See a brief demonstration of this feature of MIDI 2.0 in the below video:

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