RoboPianist Is A Simulation For Advancing Robotic Control

July 21, 2023 by Lewin Day 10 Comments

Researchers at Google have posed themselves an interesting problem to solve: mastering the piano. However, they’re not trying to teach themselves, but a pair of simulated anthropomorphic robotic hands instead. Enter RoboPianist.

The hope is that the RoboPianist platform can help benchmark “high-dimensional control, targeted at testing high spatial and temporal precision, coordination, and planning, all with an underactuated system frequently making-and-breaking contacts.”

If that all sounds like a bit much to follow, the basic gist is that playing the piano takes a ton of coordination and control. Doing it in a musical way requires both high speed and perfect timing, further upping the challenge. The team hopes that by developing control strategies that can master the piano, they will more broadly learn about techniques useful for two-handed, multi-fingered control. To that end, RoboPianist models a pair of robot hands with 22 actuators each, or 44 in total. Much like human hands, the robot hands are underactuated by design, meaning they have less actuators than their total degrees of freedom.

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Building The Cheapest MIDI Home Studio From 1988

July 19, 2023 by Lewin Day 7 Comments

These days, there is a plethora of cheap hardware and software which you can use to make digital music. Back in the 1980s, though, this was still a nascent field, with new gear changing the game for musicians. In his latest video, [cTrix] puts together a guide to building a budget MIDI home studio like it’s 1988.

The original Atari ST is the star of the show, which sold for around £300 back then. Unlike most contemporary computers, it came with MIDI ports built-in, and it quickly became a popular platform for music sequencing and controlling external synth hardware. It was often spotted in posh studios being used by big-time musicians, but [cTrix] wanted to look at how it was used by more humble users.

While the Atari ST could output some passable chiptunes, it was most powerful when paired with off-board gear. Industry magazines would readily talk up “DIY” setups worth thousands, but [cTrix] aimed for a budget in the low hundreds. In 1988, that might get you something like the 16-channel Yamaha PSS-580, which rocked full MIDI support and a ton of sounds and drumkits built in. It ran an OPL soundchip, and could play multiple instruments at once under MIDI control from software like Dr. T’s MIDI Recording Studio.

Of course, if you’ve ever played a keyboard like the PSS-580, you’ll have noted that the sound output can be more than a little chintzy. A cheap way to level up was to get yourself something like the Roland MT-32, which rocked a far higher-quality sound module. Everything from slap bass to solid electric pianos could be blasted out from the Roland, which also included a decent reverb unit, too. [cTrix] also dives into other budget heroes, like the rich and expansive Kawai K1 and the Yamaha EMT-10.

If you want to make music like it’s 1988 and you’re hunting for your first gold record, you’ll learn a lot here. We can’t wait for Part 2, that explores the next level of sophistication in this era. His previous lessons on how to make 90s dance bangers on the Amiga are a treat, too.

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Roboticized Zelda Ocarina Plays Itself

July 13, 2023 by Lewin Day 10 Comments

[3DSage] has long been obsessed with a certain type of musical instrument after playing The Legend of Zelda: Ocarina of Time. It spawned a project to robotically control an ocarina, which turned out beautifully.

The first step was to build an air blower that could excite the ocarina into making noise. With that completed, [3D Sage] then 3D scanned an ocarina so he could design a mechanism that would fit the instrument and let it be played. The final design uses a set of solenoids with rubber caps to plug the various holes of the ocarina to play different notes. The solenoids are actuated according to notes pressed on a printed keyboard. Alternatively, it can be programmed to play pre-stored songs by itself.

The results are charming, though the ocarina does sound a little off-pitch. Overall, though, the project is a great use case for a 3D scanner, since the instrument itself is such an odd irregular shape.

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Horror Instrument Is Truly Astounding To Listen To

July 12, 2023 by Lewin Day 9 Comments

Truly new musical instruments don’t come along every day; much of the low hanging fruit has already been taken. [Simon the Magpie] has been working on something that’s just a little innovative, and built what he refers to as an “Incredible Horror Instrument.” It’s all about feedback.

The build started with the Suzuki Andes 25F, a so-called “keyboard recorder.” It has the appearance of a melodion but produces flute-like sounds. [Simon]’s idea was to combine the breath-powered instrument with a talk box. If you’re unfamiliar, a talk box is designed for playing amplified guitar sounds through a tube that is placed in a player’s mouth so they can “shape” the guitar sound with their mouth.

In this role, though, the talk box’s input is hooked up to a microphone which captures the output of the Andes 25F. It then plays this back through a tube connected to the breath input of the Andes 25F. [Simon] thus created a feedback look that can effectively be “played” via the keyboard on the Andes 25F.

The audible results are eerie and haunting, and seem more than fitting for even a well-budgeted horror film. [Simon] also demonstrates some neat possibilities when combining the setup with a further feedback loop that feeds in other tones.

We’ve covered [Simon’s] work before; it’s often noisy and always entertaining. Video after the break.

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Ferrofluid Drum Synth Dances To The Beat

June 15, 2023 by Donald Papp 17 Comments

[Love Hultén]’s work often incorporates reactive sound elements, and his Ferrofluid drum synth is no exception. Sadly there are no real build details but have no fear: we’ve gathered plenty of DIY insights when it comes to ferrofluid-based projects.

Ferrofluid isn’t easy to work with, but there are plenty of DIY resources to make things easier.

First of all, ferrofluid is shockingly expensive stuff. But if you can get your hands on some old VHS tapes and acetone, you can make your own. Second, working with ferrofluid to make reactive elements is harder than it may look. Particularly, making the stuff dance to sound beats isn’t as simple as putting a container of the stuff in front of a speaker coil, but people have discovered a few ways that work more reliably than others.

[Love Hultén]’s drum synth was inspired by this custom Bluetooth speaker with dancing ferrofluid by [Dakd Jung], which drives an electromagnetic coil with frequencies selected from the audio with an MSGEQ7 equalizer. That way, only frequencies that work best for moving the fluid in interesting ways get used for the visualization. The MSGEQ7 spectrum analyzer chip is very useful for music-driven projects, as demonstrated by these sound-reactive LED shades which illustrate the audio element nicely.

The coils that create the electromagnetic field causing ferrofluid to move can take different forms, but two very interesting ones are this 12-layer PCB coil and for more intricate displays, there’s a 12×21 coil array that creates a dot-matrix-like display.

We have one last tip to share about enclosures. Some readers may have noticed that this drum synth project is housed in what looks like a piece of painted lumber. Wood is certainly a versatile material for making custom shapes, and for lettering and labels it turns out that toner transfer works just as well on wood as it does for making custom PCBs.

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Musical Robot Lets You Play The Recorder Hands-Free

May 29, 2023 by Robin Kearey 6 Comments

Although many people might remember the recorder as just a simple instrument from their introductory music classes, it can nevertheless produce rich and varied melodies in the hands of a virtuoso like Frans Brüggen. [Luis Marx] also took music lessons as a child, but never progressed much beyond an elementary level. Instead, he preferred to spend his time honing his engineering skills, which eventually enabled him to get back into music.

Initially, he wanted to build a piano-playing exoskeleton, to marionette his fingers up and down the ivories, but had to bail on that one because of the insane complexity. So instead, he built himself a robot that helps him play the recorder. (Video, in German, embedded below, fast-forwarded to the recorder part.)

A recorder has eight finger holes, which can be covered or uncovered in various combinations to produce tones. [Luis] therefore used eight solenoids, mounted on a 3D-printed frame, to actuate the finger holes. The basic idea worked, but getting the solenoids to fully cover the holes each time turned out to be a challenge: even a slight misalignment would cause air to leak past the plug and produce a horrible off-key sound.

After a lot of trial and error, [Luis] found foam earplugs to be a pretty good material for emulating human fingertips. He also discovered that relying on the solenoids’ spring tension to keep the holes closed was not reliable; a better solution was to flip the solenoids around and use the much larger force from their powered stroke to create an air-tight seal.

The solenoids are driven by an Arduino Nano through a set of MOSFET modules, powered by a lithium battery. [Luis] wrote some Arduino sketches with famous melodies like Beethoven’s Für Elise, which sound quite decent on the robo-recorder: perhaps not on Frans Brüggen’s level, but pretty impressive for a self-declared “music noob” like [Luis].

Many robotic musicians play instruments like pianos or xylophones. Instruments from the flute family are harder to automate, but it has been done before. We’ve even seen a MIDI-powered harmonica.

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We’ve Got A Saxaboom At Home Son

May 21, 2023 by Matthew Carlson 6 Comments

Most parents have heard a familiar story. Their lovely child comes up, having seen a celebrity rocking out with a funny $20 toy from the 80s, and asks for it. Of course, you reply, it’s just 20 dollars. However, a quick scan through eBay reveals that everyone else’s kid has also been asking for this obscure toy for a school event, which now costs around $700. [Ben] found himself in that exact position and made a crucial off-hand comment, “I bet I could make one of those.” That was how his hectic journey into the world of toy reproduction began.

All [Ben] had for reference when recreating a Sax-A-Boom were pictures and sound clips. Modeling complex sweeping shapes in CAD is difficult, and [Ben] commissioned a 3d model from a professional on Fiverr. [Ben] broke down the model into printable sections and tweaked it to account for buttons. After a concerning amount of putty, wet sanding, and elbow grease, [Ben] had a decently smooth body for an instrument. The device’s guts is an ESP32-based board called Sonatino, built around music generation. The music samples came from a virtual instrument clone on GitHub and loaded onto an SD card.

Time pressure crept in towards the end, and [Ben] had to go for some dirty solution that he would have preferred (popsicle sticks and epoxy for button mounting). Yes, there were some gaps and paint flaws, but ultimately [Ben’s] son rocked the school presentation. It’s a beautiful journey through creating something with a high level of finish on a limited timescale.

Perhaps future versions of the Sax-A-Boom can take it further by adding a breath sensor, like this 3d printed MIDI instrument.

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