Musical Hacks

1382 Articles

Audio Synthesizer Hooked Up With ChatGPT Interface

December 25, 2023 by 15 Comments

ChatGPT is being asked to handle all kinds of weird tasks, from determining whether written text was created by an AI, to answering homework questions, and much more. It’s good at some of these tasks, and absolutely incapable of others. [Filipe dos Santos Branco] and [Edward Gu] had an out of the box idea, though. What if ChatGPT could do something musical?

They built a system that, at the press of a button, would query ChatGPT for a 10-note melody in a given musical key. Once the note sequence is generated by the large language model, it’s played out by a PWM-based synthesizer running on a Raspberry Pi Pico.

Ultimately, ChatGPT is no musical genius. It’s simply picking a bunch of notes from a list that are known to work together melodically; that’s the whole point of musical keys. It would have been wild if it generated some riffs on the level of Stairway to Heaven or Spontaneous Devotion, but that might be asking for too much.

Here’s the question, though. If you trained a large language model, but got it to digest sheet music instead of written texts… could it learn to write music in various genres and styles? If someone isn’t working on that already, there’s surely an entire PhD you could get out of that idea alone. We should talk!

In any case, it’s one of the more creative projects from the ever-popular ECE 4760 class at Cornell. We’ve featured a bunch of projects from the class over the years, and noted how the course now runs on the RP2040. Continue reading “Audio Synthesizer Hooked Up With ChatGPT Interface” →

Raspberry Pi Pico Becomes MIDI-Compatible Synth

December 22, 2023 by 13 Comments

ECE 4760 is a microcontroller course that runs at Cornell every year, and it gives students a wide remit to pursue various kinds of microcontroller projects. [Pelham Bergesen] took the class and built himself a MIDI-controllable synthesizer out of a Raspberry Pi Pico.

[Pelham] coded a library to parse MIDI messages on the Pico, with the microcontroller’s UART charged with receiving the input data. MIDI is basically just serial at a baud rate of 31.25k, with a set message structure, after all. From there, the Pico takes the note data and plays the relevant frequencies by synthesizing square waves using a PWM output. A second PWM channel can also be blended with the first to generate more complex tones.  The synthesizer is designed to be used with a source of MIDI note data such as a keyboard controller; [Pelham] demonstrates the project in use with a Roland JD-XI. It’s a fairly basic synthesizer, but [Pelham] does a good job of explaining all the steps required to get this far. If you’ve never done an audio or MIDI project before, you might find his guide very helpful for the way it steps through the basics.

[Pelham] didn’t get to implement fancier features like direct digital synthesis (DDS) or analog audio effects before the class closed out. However, that would be an excellent project for anyone else developing their own Pico synthesizer. If you whip up something that sounds good, or even just interesting, be sure to notify us on the tipsline. Video after the break.

Continue reading “Raspberry Pi Pico Becomes MIDI-Compatible Synth” →

$30 Guitar Build Shows What You Can Do With Amazon Parts

December 22, 2023 by 20 Comments

Most guitarists buy their axes fully assembled from big names like Fender, Gibson, and… maybe Yamaha? Sure. But there are a dedicated set that relish in mixing and matching parts and even building and assembling their own instruments. [Danny Lewis] decided to see what he could do with the cheapest guitar parts from Amazon and a body of his own design, and he put together something pretty passable for just $30.

The wood for the body was cut on a bandsaw, and was essentially free scrap sourced from old furniture. [Danny] went for an unconventional design using a roughly Telecaster outline and large cutouts either side of the bridge. The neck was free, by virtue of being an old Harmony neck sourced off Craigslist. We’d have preferred to see what could be done with a cheap Amazon neck, but it nonetheless fits the vibe of the build.

The guitar then received a $9.99 pickup and controls, an $8.80 solidtail bridge, and $11 tuning machines for the headstock. Strung up, it actually sounds passable. We’d want to throw it on a proper amp and give the whole thing a setup before fully assessing it, but hey, for $30, it’s hard to go wrong.

We do love some hacky guitars around here; we’ve even featured some with surprise effects gear built into the bodies. Video after the break.

Continue reading “$30 Guitar Build Shows What You Can Do With Amazon Parts” →

Making A Guitar Go To Eleven, The Hard Way

December 21, 2023 by 10 Comments

At the end of the day, all it takes to make a guitar go to eleven is a new knob. Making the knob is another thing — that takes a shop full of machine tools, the expertise to use them, and a whole bunch of time. Then again, if you’re pressed for time, it looks like a 3D printer will do nicely too.

While the 3D printing route is clearly the easier option, it sure seems as if [Chronova Engineering] is more about the journey than the destination. In need of some knob bling for an electric guitar, he takes us through the lengthy process (nicely summarized in the video below) of crafting one from a bar of solid brass. Like all good machining projects, this one starts with making the tools necessary to start the actual build; in this case, it’s a tool to cut the splines needing to mate with the splines on the guitar’s potentiometer shaft. That side quest alone represents probably a third of the total effort on this project, and results in a tool that’s used for all of about 30 seconds.

Aside from spline cutting, there are a ton of interesting machining tidbits on display here. We particularly liked the use of a shaping technique to form the knurling on the knob, as opposed to a standard rotary method, which would have been difficult given the taper on the knob body. Also worth noting are the grinding step that puts a visually interesting pattern on the knob’s top surface, as well as the pantograph used to etch the knob’s markings.

Congrats to [Chronova Engineering] for a great-looking build, and the deep dive into the machinist’s ways. If you’re still interested in custom brass knobs but don’t have a machine shop, we can help with that.

Continue reading “Making A Guitar Go To Eleven, The Hard Way” →

Arduino Auto-Glockenspiel Looks Proper In Copper

December 16, 2023 by 19 Comments

What is it about solenoids that makes people want to make music with them? Whatever it is, we hope that solenoids never stop inspiring people to make instruments like [CamsLab]’s copper pipe auto-glockenspiel.

At first, [CamsLab] thought of striking glasses of water, but didn’t like the temporary vibe of a setup like that. They also considered striking piano keys, but thought better of it when considering the extra clicking sound that the solenoids would make, plus it seemed needlessly complicated to execute. So [CamsLab] settled on copper pipes.

That in itself was a challenge as [CamsLab] had to figure out just the right lengths to cut each pipe in order to produce the desired pitch. Fortunately, they started with a modest 15-pipe glockenspiel as a proof of concept. However, the most challenging aspect of this project was figuring out how to mount the pipes so that they are close enough to the solenoids but not too close, and weren’t going to move over time. [CamsLab] settled on fishing line to suspend them with a 3D-printed frame mounted on extruded aluminium. The end result looks and sounds great, as you can hear in the video after the break.

Of course, there’s more than one way to auto-glockenspiel. You could always use servos.

Continue reading “Arduino Auto-Glockenspiel Looks Proper In Copper” →

The Small And Silly Synth Now Even Smaller (But Just As Silly)

December 16, 2023 by 9 Comments

What do you do when you’ve carved out a niche for yourself as a builder of small and useless synthesizers? Why, build an even smaller and less useful synthesizer, of course!

If you’ve been paying even a minimal amount of attention you’ll know right away that this comes to use from [mitxela], who while not playing with volumetric POV displays is often found building smaller and smaller synthesizers, including putting them in DIN plug shells. The current synth is based on his “Silly Synth,” which puts all the guts for the synth inside a USB connector. This time around, though, it’s USB-C, and rather than fitting everything inside the connector shell, the entire synth sits on a PCB that’s smaller than a tiny piezo speaker. The whole thing runs on a CH32V003 microcontroller, and aside from a few support components and the right-angle USB-C plug, not much else.

The PCB is what really shines in [mitxela]’s design, especially the routing. He’s got a 20-pin QFN chip on one side of the board and the USB plug right behind it on the other side to deal with, plus the big through-holes for the speaker and the physical connections on the plug. It’s quite a crowded design, but it gets the job done. What’s more, he panelized the design so that mass production is possible; the reason for this is revealed at the end of the video below.

Pretty much every time we see one of these “smallest synth” videos we’re convinced that we’re seeing the lower limit of what’s possible, but every time, [mitxela] goes ahead and proves us wrong. That’s fine, of course — we don’t mind being wrong about something like this.

Continue reading “The Small And Silly Synth Now Even Smaller (But Just As Silly)” →

It’s A Microphone And A Spring Reverb All In One

December 15, 2023 by 8 Comments

We’re so used to reverb effects being simply another software plugin that it’s easy to forget the electromechanical roots of the effect. Decades ago, a reverb would have been a metal spring fed at one end with a speaker and attached at the other to a microphone. You may not see them often in the 2020s, which is probably why [Ham-made] has produced one. It’s not the type with a speaker providing the sound, though. Instead, this is a microphone in its own right with a built-in spring line.

Perhaps it’s not the best microphone possible, with a somewhat heavy diaphragm and 3D printed body. But the hand-wound spring transmits the sound down to a piezo disk which serves as the electrical element, and the whole thing screws together into quite the usable unit. There are a selection of sample MP3 files that provide an interesting set of effect-laden sounds, so if you fancy building one yourself, you can judge the results.

We think this may be the first reverb microphone we’ve seen, but we’re certainly no stranger to reverb projects. More common by far, though, are plate reverbs, in which the physical element in the system is a metal plate rather than a spring. We like it when the sound source is a Commodore 64.