Musical Hacks

1470 Articles

Rock ‘n Roll With 3D-Printed Tonewheels

November 7, 2019 by 4 Comments

What can you do with ferromagnetic PLA? [TheMixedSignal] used it to give new meaning to the term ‘musicians’ gear’. He’s made a proof of concept for a DIY tone generator, which is the same revolutionary system that made the Hammond organ sing.

Whereas the Hammond has one tonewheel per note, this project uses an Arduino to drive a stepper at varying speeds to produce different notes. Like we said, it’s a proof of concept. [TheMixedSignal] is proving that tonewheels can be printed, pickups can be wound at home, and together they will produce audible frequencies. The principle is otherwise the same — the protruding teeth of the gear induce changes in the magnetic field of the pickup.

[TheMixedSignal] fully intends to expand on this project by adding more tone wheels, trying different gear profiles, and replacing the stepper with a brushless motor. We can’t wait to hear him play “Karn Evil 9”. In the meantime, put on those cans and check out the demo/build video after the break.

We don’t have to tell you how great Hammond organs are for making music. But did you know they can also encode secret messages?

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DIY Cassette Tape Guitar Delay

November 3, 2019 by 19 Comments

Digital delay pedals are pretty good nowadays and even the cheaper ones do a pretty good job at emulating the sound of old analog delay effects. And that’s good, because the original delay effects can run you a pretty penny. If you’re in to DIY electronics, though, analog delay effects can still be built without breaking the bank, and, as an example, [Matsound] has made a tape delay using an old tape deck and regular cassette tapes.

The core of the build is a portable 3-head cassette recorder, in this case a Marantz PMD430. The circuit has been around for a while – it was originally found in an issue of Stompboxology in the 90’s. The basic idea is that with a three-head recorder (erase, record, play) the distance between the record and play heads creates a delay and you increase this delay by slowing down the recorder’s motor. You combine the output from the recorder with the dry signal from your input and, viola, tape delay.

[Matsound] added a cool feature where you can control the speed of the motor with a control voltage, so if you connect it to a keyboard and produce different voltages from different keys, you get weird, spacey effects. The video gives an overview of the features and some details of the build process are in the video’s description.

A nice build built into a nice case and a great effect! Maybe you wouldn’t take it out gigging with you, but it sure sounds pretty good!  Other delay pedals have been mentioned on the site before, like this digital delay pedal and here’s another take on the cassette tape delay.

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World’s Smallest MIDI Synth, Now Even Better

October 28, 2019 by 6 Comments

We’re pretty sure there’s no internationally recognized arbiter of records like “World’s smallest full-featured polyphonic stereo MIDI synthesizer that fits in a DIN shell”. If there isn’t, there sure should be, and we’re pretty sure [mitxela]’s Flash-Synth would hold that particular record.

This is one of those lessons that some people just can’t leave a challenge alone. First [mitxela] built a MIDI synthesizer into a DIN connector, then a couple of months later he made a somewhat more streamlined version. While both were feats of engineering derring-do, neither was entirely satisfactory. With only square wave synthesis and a limit of eight voices, plus some unpleasant audio issues and a total lack of manufacturability, the next challenge was clear.

We won’t pretend to follow all the audio arcana, of which the video below and the build log have plenty, but the technical achievement is obvious enough. The Flash-Synth has an STM32, a tantalum SMD filter capacitor that dwarfs it, and a few support components on a flexible PCB that folds back on itself twice. This bit of circuit origami is connected to a 5-pin DIN plug and stuffed into the connector’s shell, which in turn mates to a custom-machined metal housing. A stereo audio jack lives at the other end of the assembly, and the whole synth is powered parasitically off the MIDI port.

The first half of the video below is mostly a demo that proves the synth sounds great and can do just about anything; skip to the 22-minute mark for the gory build details. Suffice it to say that [mitxela]’s past experience with ludicrous scale soldering served him well here.

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Turntable Spins Color And Sound Together

October 27, 2019 by 5 Comments

If you can’t grow your own synesthesia, buying electronics to do it for you is fine. Such is the case with the CHROMATIC by [Xavier Gazon], an artist who turns all kinds of electronics into circuit-bent musical art pieces. His project turns an old Philips Music 5120 turntable into a colorful MIDI sequencer, inspired by older 20th century instruments such as the Optophonic Piano and the Luminaphone.

The CHROMATIC uses colored pucks placed on a converted turntable to perform a looping sequence of chords in a given musical scale, generating MIDI data as output. Where its inspirations used primitive optics as their medium, this project employs a Teensy microcontroller and two modern optical sensors to do the work. One of these is a simple infrared sensor which tracks a white spot on the edge of the turntable, generating a MIDI clock signal to keep everything quantized and in sync. The other is a color sensor mounted on the tone arm, which can tell what color it sees and the height of the arm from the turntable.

While the instrument is still in beta testing phase details on how notes are generated aren’t yet given, though the general idea is that they are dictated by the color the tone arm sees and its position above the platter. Moving the tone arm changes which pucks it tracks, and the speed of the turntable can also be adjusted, changing how the melody sounds.​

The CHROMATIC is a very interesting project, but it’s not the first optical-based turntable hack we’ve seen here. We’ve also seen a much weirder use for a color sensor, too. Check out the video of this one in action after the break.

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It’s A TV-Scope-Guitar Amplifier!

October 26, 2019 by 8 Comments

Guitar amplifiers are a frequent project, and despite being little more than a simple audio amplifier on paper, they conceal a surprising quantity of variables in search of a particular sound. We’ve seen a lot of them, but never one quite like [Nate Croson]’s CRT TV guitar amplifier. The LM386 doesn’t just drive the speaker, he’s also using it to turn the TV into a crude oscilloscope to form a visualisation of the sound.

The video showing this feat is below the break, and it puts us in a quandary due to being short on technical information. He’s driving the horizontal coils with the TV’s 50 Hz sawtooth field timebase, and the vertical ones with the audio from the LM386. We aren’t sure whether he’s rotated the yoke or whether the connections have been swapped, but the result is certainly impressive.

So given that there’s not quite as much technical detail as we’d like, why has this project captured our interest? Because it serves as a reminder that a CRT TV is a bit more than a useless anachronism, it’s a complex analogue device with significant and unique hacking potential. The older ones in particular provide endless possibilities for modification and circuit bending, and make for a fascinating analogue playground at a very agreeable price. It’s worth pointing out however that some of the voltages involved can make them a hazardous prospect for the unwary hacker. If you’re interested though, take a look at our dive into an older model.

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Wiping Your Windscreen To The Beat

October 24, 2019 by 32 Comments

Nothing spoils your mood quite like your windscreen wipers not feeling it when the beat drops. Every major car manufacturer is focused on trying to build the electric self driving vehicle for the masses, yet ignoring this very real problem. Well [Ian Charnas] is taking charge, and has successfully slaved his car’s wipers to beat of its stereo.

Starting with the basics, [Ian] first needed to control the speed of the wiper motor. This was done using a custom power supply adapted from another project. The brain of the system is a Raspberry Pi 3B+ which runs a phase locked loop algorithm to sync the music and the motor. Detecting the beat turned out to be the most difficult part of the project, and from the research [Ian] did, there is no standard solution. He ended up settling on “madmom“, a Python audio and music signal processing library, which runs a neural net to detect the beat in real time. The Raspi sends the required PWM and Enable signals to an Arduino over serial, which in turn controls the power supply. The entire system was neatly integrated in the car, with a switch in the dash that connects the motor to the new power supply on demand, to allow the wipers to still be used normally (and safely).

[Ian] filed a provisional patent application for the idea, and will be putting it on auction on eBay soon, with the hope that some major car manufacturer would be interested. For older cars, you can shove an Arduino into the stereo, or do a super cheap bluetooth upgrade. Check out the video after the break. Continue reading “Wiping Your Windscreen To The Beat” →

DIY MIDI Looper Controller Looks Fantastic!

October 13, 2019 by 4 Comments

Due to pedalboard size, complicated guitar pedals sometimes reduce the number of buttons to the bare minimum. Many of these pedals are capable of being controlled with an external MIDI controller, however, and necessity being the mother of invention and all, this is a great opportunity to build something and learn some new skills at the same time. In need of a MIDI controller, Reddit user [Earthwin] built an Arduino powered one to control his Boss DD500 Looper pedal and the result is great looking.

Five 16×2 LCD screens, one for each button, show the functionality that that button currently has. They are attached (through some neat wiring) to a custom-built PCB which holds the Arduino that controls everything. The screens are mounted to an acrylic backplate which holds the screens in place while the laser-cut acrylic covers are mounted to the same plate through the chassis. The chassis is a standard Hammond aluminum box that was sanded down, primed and then filler was used to make the corners nice and smooth. Flat-top LEDs and custom 3D printed washers finish off the project.

[Earthwin] admits that this build might be overkill for the looper that he’s using, but he had fun building the controller and learning to use an Arduino. He’s already well on his way to building another, using the lessons learned in this build. If you want to build your own MIDI controller, this article should help you out. And then you’re ready to build your controller into a guitar if you want to.

[Via Reddit]