MIDI Mouse Makes Marvelous Music

July 18, 2021 by 5 Comments

It’s an old misconception that digital musicians just use a mouse and keyboard for their art. This is often far from the truth, as many computer music artists have a wide variety of keyboards/synths, MIDI controllers, and “analog” instruments that all get used in their creative process. But what if one of those instruments was just a mouse?

Well, that must have been what was going through [kzra]’s mind when he turned an old ps/2 roller ball mouse into an electronic instrument. Born out of a love for music and a hate for waste, the mouse is a fully functional MIDI controller. Note pitch is mapped to the x-coordinate of the pointer, and volume (known as velocity, in MIDI-speak) is mapped to the y-coordinate. The scroll wheel can be used as a mod wheel, user-configurable but most often used to vary the note’s pitch. The mouse buttons are used to play notes, and can behave slightly differently depending on the mode the instrument is set to.

Not satisfied with simply outputting MIDI notes, [kzra] also designed an intuitive user interface to go along with the mouse. A nice little OLED displays the mode, volume, note, and mouse coordinates, and an 8×8 LED matrix also indicates the note and volume. It’s a fantastic and versatile little instrument, and you’ve gotta check out the video after the break to see it for yourself. We’ve seen some awesome retro-tech MIDI controllers before, and this fits right in.

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MIT’s Knitted Keyboard Is Quite A Flexible MIDI Controller

June 30, 2021 by 7 Comments

There are only so many ways to make noise on standard instruments such as acoustic pianos. Their rigidity and inputs just don’t allow for a super-wide range of expression. On the other hand, if you knit your interface together, the possibilities are nearly endless. MIT’s new and improved knitted keyboard is an instrument like none other — it responds to touch, pressure, and continuous proximity, meaning that you can play it like a keyboard, a theremin, and something that is somewhere in between the two. Because it’s a MIDI interface, it can ultimately sound like any instrument you’ve got available in software.

The silver keys of this five-octave interface are made of conductive yarn, and the blue background is regular polyester yarn. Underneath that is a conductive knit layer to complete the key circuits, and a piezo-resistive knit layer that responds to pressure and stretch. It runs on a Teensy 4.0 and uses five MPR121 proximity/touch controllers, one per octave.

The really exciting thing about this keyboard is its musical (and physical) versatility. As you might expect, the keyboard takes discrete inputs from keystrokes, but it also takes continuous input from hovering and waving via the proximity sensors, and goes even further by taking physical input from squeezing, pulling, stretching, and twisting the conductive yarns that make up the keys. This means it takes aftertouch (pressure applied after initial contact) into account —  something that isn’t possible with most regular instruments. And since this keyboard is mostly yarn and fabric, you can roll it up and take it anywhere, or wrap it around your neck for a varied soundscape.

If you’re looking for more detail, check out the paper for the previous version (PDF), which also used thermochromic yarn to show different colors for various modes of play using a heating element. With the new version, [Irmandy Wicaksono] and team sought to improve the sensing modalities, knitted aesthetics, and the overall tactility of the keyboard. We love both versions! Be sure to check it out after the break.

Want to play around with capacitive touch sensors without leaving the house for parts? Make your own from paper and aluminum foil.

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MIDI All The Things Hack Chat

March 22, 2021 by 5 Comments

Join us on Wednesday, March 24 at noon Pacific for the MIDI All the Things Hack Chat with Tim Alex Jacobs!

In our technologically complex world, standards are a double-edged sword. While they clearly make it possible for widgets and doodads to interoperate with each other, they also tend to drift away from their original intention over time, thanks to the march of progress or even market forces. If there’s one thing you can expect about standards, it’s that they beget other standards.

One standard that has stood the test of time, with modification of course, is the Musical Instrument Digital Interface, or MIDI. It’s hard to overstate the impact MIDI has had on the music world since it was first dreamed up in the early 1980s. Started amid a Wild West of competing proprietary synchronization standards, MIDI quickly became the de facto interface for connecting electronic musical instruments together. And as it did, it moved from strictly pro-grade equipment down the market to prosumer and home users, fueled in part by the PC revolution.

Tim Alex Jacobs, who is perhaps better known as Mitxela on his YouTube channel, has long been interested in applying MIDI to unusual corners of the musical world. We’ve seen him MIDI-fy things that barely qualify as musical instruments, and also build a polyphonic synthesizer so small it fits within the shell of the DIN connector that’s so strongly associated with the MIDI standard. Tim joins us on the Hack Chat this week to talk about his experiences with MIDI, and to help us understand all the ways we can work with the interface in our builds.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, March 24 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
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Simple Slide Whistle Gets A MIDI Makeover

February 10, 2021 by 6 Comments

On today’s episode of “Will it MIDI?” we have the common slide whistle. Spoiler alert: yes, it will, and the results are just on the edge of charming and — well, a little weird.

As maker [mitxela] points out, for all its simplicity, the slide whistle is a difficult instrument to play. Or, at least a difficult one to hit a note repeatably. It’s a bit like a tiny plastic trombone, in that both lack keys or stops that limit the vibrating column of air to a specific length. Actually, the beginning of the video below shows a clever fix for that problem on the slide whistle using magnets, but that’s mainly a side project.

[mitxela]’s MIDI-fication of the slide whistle required a bit more than a few magnets. To move the slide to defined positions, a pair of high-precision servos was connected by a laser-cut plywood scissors linkage. The lung-power of the musician is replaced by a small electric blower, mounted away from the whistle and supplying air through a long hose. The fan’s speed, and therefore the speed of the airflow, can be varied; this prevents low notes from shifting up in register from over-blowing, if that’s the right term. Another servo controls a damper that shuts off the flow of air from the mouth of the whistle to control notes without having to turn off the fan completely. The main article goes into detail about the control electronics and the calibration process.

The video has a few YouTube copyright strikes demo songs, and we have to say we’re impressed with the responsiveness of the mechanism. Some will object to the excess servo noise, but we found it nice — almost like guitar string-squeak. We like the tunes where [mitxela]’s servo-plucked music box joined in, too.

Mattress-made MIDI Device Plays Exotic Tunes

January 2, 2021 by 5 Comments

Ever heard of a handpan? If not, imagine a steel drum turned inside out, and in case that doesn’t help either, just think of a big metal pan you play music with by tapping your hands on its differently pitched tone fields. But as with pretty much any musical instrument, the people around you may not appreciate your enthusiasm to practice playing it at any time of the day, and being an acoustic instrument, it gets difficult to just plug in your headphones. Good news for the aspiring practitioners of Caribbean music though, as [Deepsoul77] created a MIDI version of this rather young and exotic instrument.

Using the foam salvaged from an old mattress as the core of the handpan, [Deepsoul77] cut a couple of plywood pads as tone fields that will be attached to the foam. Each plywood tone field will then have a piezo element mounted in between to pick up the hand tapping. Picking up the tapping itself and turning it into MIDI signals is then handled by an Alesis trigger interface, which is something you would usually find in electronic drums. From here on forward, it all becomes just a simple USB MIDI device, with all the perks that brings along — like headphone usage or changing MIDI instruments to make anything sound like a trumpet.

Turning what’s essentially a drum kit into a melodic instrument is definitely neat, and to no surprise, we’ve also seen the actual home made drum kit with piezo elements. Of course, using MIDI to quiet down an acoustic instrument isn’t new either, though it also works somewhat the other way around. But then again, it doesn’t always have to be MIDI either.

76-bit Trombones Led By The Big MIDI File

December 27, 2020 by 30 Comments

Inspired by the creative genius of Martin Molin of Wintergatan fame, [iSax] set out to create a robotic MIDI-controlled trombone. It takes years for humans to develop the control and technique required to play the trombone well as the tone produced into the mouthpiece (embouchure) is a tricky combination of air pressure, lip tension, airflow, resonance in the mouth, and other sources of complex pressure.

[iSax] gives a thorough walkthrough of the machine, which is powered by two separate sources of air, one for the position of the slide and the other for producing sound. A potentiometer provides feedback on the position of the slide and a servo controls the flow rate into the silicone resonance chamber. The chamber can be tuned via a stepper motor that applies pressure, slightly altering the chamber’s frequency and pressure. An Arduino with Firmata allows the device to controlled easily from any host computer. A detailed writeup in PDF form is on the Hackday.io project page.

As you can imagine, simulating a human mouth is a daunting task and the number of variables meant that [iSax] ended up with something only vaguely trombone-like. While ultimately it didn’t turn out to be the astounding music machine that [iSax] hoped, it did end up being a fun feat of engineering we can appreciate and admire. Progress towards automatic brass instruments seems to be coming slowly as we saw similar results with this robotic trumpet. Maybe someday we’ll have robot brass sections, but not today.

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A Pair Of Steppers Are Put To Work In This Automatic Instrument Pickup Winder

December 13, 2020 by 7 Comments

For something that’s basically a coil of wire around some magnetic pole pieces, an electric guitar pickup is a complicated bit of tech. So much about the tone of the instrument is dictated by how the pickup is wound that controlling the winding process is something best accomplished with a machine. This automatic pickup winder isn’t exactly a high-end machine, but it’s enough for the job at hand, and has some interesting possibilities for refinements.

First off, as [The Mixed Signal] points out, his pickups aren’t intended for use on a guitar. As we’ve seen before, the musical projects he has tackled are somewhat offbeat, and this single-pole pickup is destined for another unusual instrument. That’s not to say a guitar pickup couldn’t be wound on this machine, of course, as could inductors, solenoids, or Tesla coils. The running gear is built around two NEMA-17 stepper motors, one for the coil spindle and one for the winding carriage. The carriage runs on a short Acme lead screw and linear bearings, moving back and forth to wind the coil more or less evenly. An Arduino topped with a CNC shield runs the show, allowing for walk-away coil winding.

We do notice that the coil wire seems to bunch up at the ends of the coil form. We wonder if that could be cured by speeding up the carriage motor as it nears the end of the spool to spread the wire spacing out a bit. The nice thing about builds like these is the ease with which changes can be made — at the end of the day, it’s just code.

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