An Effects Pedal For Keyboards (and Mice)

August 21, 2023 by Bryan Cockfield 4 Comments

Effects pedals for musical instruments like electric guitars can really expand a musician’s range with the instrument. Adding things like distortion, echo, and reverb at the push of a button can really transform the sound of a guitar and add depth to a performance. But [Guy] wondered why these effects should be limited to analog signals such as those from musical instruments, and set about to apply a number of effects to the use of computer keyboards and mice with this HID effects pedal.

The mouse is perhaps the closer of the two to an analog device, so the translations from the effects pedal are somewhat intuitive. Reverb causes movements in the mouse to take a little bit of extra time before coming to a stop, which gives it the effect of “coasting”. Distortion can add randomness to the overall mouse movements, but it can also be turned down and even reversed, acting instead as a noise filter and smoothing out mouse movements. There’s also a looper, which can replay mouse movements indefinitely and a crossover, which allows the mouse to act as a keyboard.

For the keyboard, included effects are a tremolo, which modulates between upper- and lower-case at certain intervals; echo, which repeats keypresses; and a pitch-shift which outputs a “higher” character in the alphabet above whichever one has been pressed. Like the mouse, there’s also a crossover mode which allows the keyboard to be used as a mouse.

The device looks and feels like an effects pedal for a guitar would, with a RP2040 inside to intercept HID information, do the signal processing, and then output the result to the computer. And, while [Guy] admits this was a fun project with not many practical uses, there are a couple handy ones including potentially the distortion effect to smooth out mouse inputs for those with neuromuscular disorders or the mouse looper to act as a mouse jiggler for those with micromanaging employers. It’s also reprogrammable, and as we’ve seen since time immemorial having a programmable foot keyboard can be extremely handy for certain workflows.

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Modeling A Guitar For Circuit Simulation

August 19, 2023 by Bryan Cockfield 20 Comments

Guitar effects have come a long way from the jangly, unaltered sounds of the 1950s when rock and roll started picking up steam. Starting in large part with [Jimi Hendrix] in the 60s, the number of available effects available to guitarists snowballed in the following decades step-by-step with the burgeoning electronics industry. Now, there are tons of effects, from simple analog devices that would have been familiar to [Hendrix] to complex, far-reaching, digital effects available to anyone with a computer. Another thing available to modern guitarists is the ability to model these effects and guitars in circuit simulators, as [Iain] does.

[Ian] plays a Fender Stratocaster, but in order to build effects pedals and amplifiers for it with the exact desired sound, he needed a way to model its equivalent circuit. For a simple DC circuit, this isn’t too difficult since it just requires measuring the resistance, capacitance, and inductance of the overall circuit and can be done with something as simple as a multimeter. But for something with the wide frequency range of a guitar, a little bit more effort needs to go into creating an accurate model. [Iain] is using an Analog Discovery as a vector network analyzer to get all of the raw data he needs for the model before moving on to some in-depth calculations.

[Iain] takes us through all of the methods of figuring out the equivalent impedance of his guitar and its cabling using simple methods capable of being done largely by hand and more advanced techniques like finding numerical solutions. By analyzing the impedance of the pickup, tone and volume controls, and cable, this deep dive into the complexities of building an accurate equivalent circuit model for his guitar could be replicated by anyone else looking to build effects for their specific guitars. If you’re looking for a more digital solution, though, we’ve seen some impressive effects built using other tools unavailable to guitarists in days of yore, such as MIDI and the Raspberry Pi.

GETMusic Uses Machine Learning To Generate Music, Understands Tracks

July 27, 2023 by Donald Papp 10 Comments

Music generation guided by machine learning can make great projects, but there’s not usually much apparent control over the results. The system makes what it makes, and it’s an achievement if the results are not obvious cacophony. But that’s all different with GETMusic which allows for a much more involved approach because it understands and is able to create music by tracks. Among other things, this means one can generate a basic rhythm and melody first, then add additional elements to those existing ones, leaving the previous elements unchanged.

GETMusic can make music from scratch, or guided from examples, and under the hood uses a diffusion-based approach similar to the method behind AI image generators like Stable Diffusion. We’ve previously covered how Stable Diffusion works, but instead of images the same basic principles are used to guide the model from random noise to useful tracks of music.

Just a few years ago we saw a neural network trained to generate Bach, and while it was capable of moments of brilliance, it didn’t produce uniformly-listenable output. GETMusic is on an entirely different level. The model and code are available online and there is a research paper to accompany it.

You can watch a video putting it through its paces just below the page break, and there are more videos on the project summary page.

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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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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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Using An Old Smartphone In Place Of A Raspberry Pi

April 27, 2023 by Bryan Cockfield 62 Comments

The Raspberry Pi was a fairly revolutionary computing device when it came on the scene around a decade ago. Enough processing power to run a full Linux desktop and plenty of GPIO meant almost certain success. In the past year, though, they’ve run into some issues with their chip supplier and it’s been difficult to find new Pis, which has led to some looking for alternatives to these handy devices. [David] was hoping to build a music streaming server and built it on an old smartphone instead of the ubiquitous single-board computer.

Most smartphones are single-board computers though, and at least the Android devices are fully capable of running Linux just like the Pi. The only problem tends to be getting around the carrier or manufacturer restrictions like a locked bootloader or lack of root access. For [David]’s first try getting this to work, he tried to install Navidrome on a Samsung phone but had difficulties with the lack of memory and had to build the software somewhere else and then load it on the phone. It did work, but the stock operating system kept killing the process for consuming too much memory.

Without root access, [David] decided to try LineageOS, a version of Android which, among other benefits, is typically much more configurable than the stock version of Android that is shipped with smartphones. This allowed him to disable or uninstall anything not needed for his music server to free up enough memory. After some issues with transcoding the actual music files he planned on streaming, his music server was successfully up and running on a phone that would have otherwise been relegated to the junk drawer. The specific steps he took to get this working can be found on his GitHub page as well.

[David] also mentioned looking at PostmarketOS for this job which is certainly a viable option for some, but the Linux distribution for phones is only supported on a few devices. Another viable alternative for a project like this if no Raspberry Pis are available might be any of a number of Pine64 devices that might also be sitting around gathering dust, like the versatile Linux-based Pinephone.