Raspberry Pi Crazy Guitar Rig Turns You Into A Hard ‘N Heavy One-Man Band

It’s a common problem: you’re at a party, there’s a guitar, and your plan to impress everyone with your Wonderwall playing skills is thwarted by the way too loud overall noise level. Well, [Muiota betarho] won’t have that issue ever again, and is going to steal the show anywhere he goes from now on with his Crazy Guitar Rig 2.0, an acoustic guitar turned electric — and so much more — that he shows off in three-part video series on his YouTube channel. For the impatient, here’s video 1, video 2, and video 3, but you’ll also find them embedded after the break.

To start off the series, [Muiota betarho] adds an electric guitar pickup, a set of speakers, and an amplifier board along with a battery pack into the body of a cheap acoustic guitar. He then dismantles a Zoom MS-50G multi-effect pedal and re-assembles it back into the guitar itself with a 3D-printed cover. Combining a guitar, effect pedal, amp and speaker into one standalone instrument would make this already an awesome project as it is, but this is only the beginning.

Touch screen and controls closeup
RPi touch screen running SunVox, plenty of buttons, and integrated multi-effect pedal on the left

So, time to add a Raspberry Pi running SunVox next, and throw in a touch screen to control it on the fly. SunVox itself is a free, but unfortunately not open source, cross-platform synthesizer and tracker that [Muiota betarho] uses to add drum tracks and some extra instruments and effects. He takes it even further in the final part when he hooks SunVox up to the Raspberry Pi’s GPIO pins. This allows him to automate things like switching effects on the Zoom pedal, but also provides I/O connection for external devices like a foot switch, or an entire light show to accompany his playing.

Of course, adding a magnetic pickup to an acoustic guitar, or generally electrifying acoustic instruments like a drum kit for example, isn’t new. Neither is using a single-board computer as effect pedal or as an amp in your pocket. Having it all integrated into one single device on the other hand rightfully earns this guitar its Crazy Guitar Rig name.

(Thanks for the tip, [alex]!)

Continue reading “Raspberry Pi Crazy Guitar Rig Turns You Into A Hard ‘N Heavy One-Man Band”

Guitar Effect Built From An Old Record Player

With little more than a gutted record player, a light bulb, and the legendary 555 timer IC, [Jacob Ellzey] has constructed this very slick optical tremolo effect for his guitar. By modulating the volume of the input signal, the device creates the wavering effect demonstrated in the video after the break.

The key is a vinyl record with large tabs cut out of it. As the record spins, these voids alternately block and unblock a small incandescent bulb. A common GL5537 photoresistor, mounted on the arm that originally held the player’s needle, picks up the varying light levels and passes that on to the electronics underneath the deck. An important note here is that different spacing and sizing of the cutouts will change the sound produced by the effect. [Jacob] has already produced a few different designs and plans on experimenting with more now that the electronics are completed.

Under the hood there’s a voltage divider and low gain amplifier connected to the photoresistor, and also a 555 timer circuit that’s driving the incandescent bulb. Once he was done fiddling with them, the circuit was moved to a neat little protoboard. A pair of potentiometers mounted through the side of the record player allow for adjusting the depth of the effect itself, as well as the output volume. Naturally, there’s also an external foot pedal that allows keying the effect on and off without taking your hands from the guitar.

As is usually the case, everything was going well on this project until the final moments, when [Jacob] found that the circuit and bulb were both browning out when powered from the same transformer. As a quick fix, he gutted a Keurig and used its transformer to drive the light bulb by itself. With independent power supplies, he was ready to rock.

Of course this isn’t the first time we’ve seen a piece of consumer electronics modified into a guitar effect, but if you’re looking for something a bit more built for purpose, there’s plenty of high-tech options to keep you busy.

Continue reading “Guitar Effect Built From An Old Record Player”

A Hard Rocking Arduino Visualization Shield

Over the summer [ElectroSmash] put the finishing touches on the Arduino Audio Meter, a shield for the Arduino Uno that visualizes various aspects of an incoming audio signal on a set of four 8×8 LED dot matrices. Obsentisibly it’s for use on a guitar pedalboard, but thanks to the incredible documentation and collection of example code provided by the team, the project promises to be an excellent platform for all sorts of audio experimentation.

Incoming audio is amplified with an MCP6002 and fed into the Uno’s Analog to Digital Converter, where it’s processed via whatever Sketch the user has uploaded. User input is provided by a digital encoder with push-button. A set of four MAX7219 chips control the entire 256-pixel matrix with just three pins on the Arduino. The resolution of the display allows the Arduino Audio Meter to show more than just a simple VU meter, it can even do text and basic graphics.

[ElectroSmash] provides various Sketches for use with the Arduino Audio Meter that provide the expected repertoire of audio visualizations, but they also provide a number of interesting Sketches to expand the capabilities of the device in unexpected ways. Some of them could be useful for a stage musician, such a tool to tune your guitar, whereas others are fun uses of the hardware such as a game of “Snake”.

With the entire project released as open source, users are free to run wild with the Arduino Audio Meter. Writing your own custom software is an obvious first step to making the project your own, but adding additional hardware features and functions certainly aren’t out of the question either.

Our very own [Lewin Day] once walked us through the effort involved in building boutique guitar pedals, and while the Audio Audio Meter’s capabilities are somewhat limited as it doesn’t have the ability to change the audio going through it, we’re still interested in seeing what the community will come up with once they have an easy way to bring their ideas to life.

Continue reading “A Hard Rocking Arduino Visualization Shield”

DIY Raspberry Pi Multi FX Stomp Box

From building your own analog effects pedal to processing audio through micro controllers, a lot of musicians love building their own boxes of sound modification. In his entry for the 2019 Hackaday Prize, [Craig Hissett] has a project to build an all-in-one multi-effects stomp box.

At the center of the box is a Raspberry Pi with an AudioInjector stereo sound card.  The card takes care of stereo in and out, and passing the signal to the Pi. The software is Modep, an open source audio processor that allows the setup of a chain of digital effects plugins to be run on the Pi. After finding some foot switches, [Craig] connected them to an Arduino Pro Micro which he set up as a MIDI device that sends MIDI messages to the Modep software running on the Pi.

There are still a few steps to go, but [Craig] has the basic layout covered. Next up is wiring it up and building a proper case for it, as well as working on latency. A few years ago, another multi-effects stomp box was featured in the Hackaday Prize, and last year, this multi-effects controller was featured.


PiFX, The Pi-Powered Pedal Board

Since the beginnings of the Raspberry Pi, [Tibbbbz] has wanted to build a DIY guitar effects board and amp simulator. A device like this, and similar ones sold by Boss and Kemper, put a bunch of processing power inside a metal enclosure with some footswitches and a pair of quarter inch jacks for input and output. Mash some buttons and wicked toanz come out the other end. Now this is actually possible with a Pi, and it’ll sound great too.

Because this is an audio application, latency is critical. It doesn’t really matter if you have 200 milliseconds of latency when scrolling through your Facebook feed, but for real-time audio processing anything over five milliseconds is disorienting and nearly unusable. [Tibbbbz] is using a standard, off-the-shelf USB audio adapter that gets the latency down to about that level. A Raspberry Pi is never going to have latency as low as a handful of transistors in a analog effects pedal, but it’s close enough.

For the audio system, it’s all about JACK audio: a wonderful frontend for the Linux audio system. The actual pedal emulation is happening with Guitarix. For the hardware part of this build, there’s actually not that much going on here apart from a USB sound card and a touch screen display. The footswitches are the most interesting as they’re wired up as buttons in a repurposed USB keyboard controller board. This repurposing of a USB keyboard is rather interesting, because it vastly simplifies the entire build. All of this is wrapped up in a wedge-shaped walnut pedalboard that’s sturdy enough to live on the stage at least part of the time. You can check out the demos here.

Hackaday Podcast Ep14: Keeping Raspberry’s SD Card Alive, We Love MRRF, And How Hot Are Flip Chips?

Elliot Williams and Mike Szczys take a look at advances in photogrammetry (building 3D models out of many photographs from a regular camera), a delay pedal that’s both aesthetically and aurally pleasing, and the power of AI to identify garden slugs. Mike interviews Scotty Allen while walking the streets and stores of the Shenzhen Electronics markets. We delve into SD card problems with Raspberry Pi, putting industrial controls on your desk, building a Geiger counter for WiFi, and the sad truth about metal 3D printing.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (61.6 MB)

Places to follow Hackaday podcasts:

Continue reading “Hackaday Podcast Ep14: Keeping Raspberry’s SD Card Alive, We Love MRRF, And How Hot Are Flip Chips?”

This Is The Delay Pedal You Can Build Yourself

If you’re looking to make money in electronics, there’s no better market than guitar pedals and modular synths. The margins are high, and all the consumers are otakus who will spend outrageous amounts of money chasing the next big thing. The products are just one step above audiophile wank with zero oxygen cables, and if your opamp sounds ‘more transparent’, you’re going to make a fortune, never mind how something can sound more transparent, whatever that is to begin with.

If you want to do something really cool, build a delay, because everyone needs another delay. If you want to build the latest in delay technology, just grab a PT2399 chip. That’s what ElectroSmash did with their Open Source Time Manipulator delay. Everything’s right there, all the parts of the circuits are described, and you too can become an effects pedal engineer.

This pedal is based on the PT2399 chip from Princeton Technology, a digital delay chip that can be used with something that sounds like an old-school bucket brigade chip or something resembling a tape echo. As a digital chip, you’ve also got the clean, clear sounds of a digital delay, with just a few tweaks of the circuit. We’ve taken a look at the PT2399 before, but surprisingly not many people are sharing their secrets.

The circuit for the ElectroSmash Time Manipulator is built around the ATMega328, the same chip in the Arduino Uno, with two PT2399s that can be configured to operate in serial or parallel for everything from a slapback echo to a 600ms digital delay. If you set everything right, you can get choruses, reverbs, or some psychobilly flange-ish sounds.

The entire circuit is open, with a board designed in KiCad, the code is right there written in C, and the only hard-to-replicate tech is the PT2399 chip itself, which can be had from the usual vendors for less than a dollar a piece. It’s a great pedal, and be sure to check out the video below.

Continue reading “This Is The Delay Pedal You Can Build Yourself”