Adding MIDI To A Mini Synth Is Easy As Pi

September 21, 2020 by Kristina Panos 11 Comments

There are a handful of relatively dirt cheap synths out there like the KORG Monotron, but many of them use ribbon controllers that aren’t very precise. Ribbon controllers basically slide pots that you operate with your finger or a stylus. They’re painted to look like piano keys in order to show you approximately where the notes are supposed to be. The Stylophone is another extremely affordable synth that does even less as a synthesizer and uses this type of input. It’s a fun input if you don’t mind imprecision, but can be annoying otherwise.

[schollz] isn’t satisfied to synth this way, so they added MIDI input to their KORG Monotron using a Raspberry Pi and a DAC. Fortunately, the Monotron is quite the hackable little synth, with nice, big, labelled pads on the PCB.

All it really took was a couple of solder joints in the right places, plus a clever Python script. The script listens for MIDI input from a keyboard, and then controls an MCP4725 DAC, which sends voltages to the Monotron. [schollz] wrote a tuning function that computes the FFT of the MIDI tones to find the fundamental frequencies of each to send along to the Monotron. Check it out after the break.

If liquid control is what you’re after but all you have is a keyboard, try making your own ribbon controller.

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Controlling A Broken Super Nintendo With MIDI

September 19, 2020 by Tom Nardi 1 Comment

A Super Nintendo that has trouble showing sprites doesn’t make for a very good game system. As it turns out, Super Mario World is a lot less fun when the titular hero is invisible. So it’s no surprise that [jwotto] ended up tossing this partially functional SNES into the parts bin a few years back.

But he recently came up with a project that may actually benefit from its unusual graphical issues; turning the glitched console into a circuit bent video synthesizer. The system was already displaying corrupted visuals, so [jwotto] figured he’d just help things along by poking around inside and identifying pins that created interesting visual effects when shorted out.

Installing the new electronics into the SNES.

Once he mapped out the pins, he wired them all up to a transistor switching board that he’d come up with for a previous project. That would let an Arduino short out the pins on command while still keeping the microcontroller relatively isolated from the SNES. Then it was just a matter of writing some code that would fire off the transistors based on MIDI input.

The end result is a SNES that creates visual glitches along with the music, which [jwotto] can hook up to a projector when he does live shows. A particularly neat feature is that each game responds in its own way, so he can swap out the cartridge to show completely different visuals without having to change any of the MIDI sequencing.

A project like this serves as a nice introduction to both circuit bending and MIDI hacking for anyone looking to get their digital feet wet, and should pair nicely with the MIDI Game Boy Advance.

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Digital Expression Via Harmonica

September 15, 2020 by Brian McEvoy 11 Comments

There is a good chance you clicked on this article with a mouse, trackball, trackpad, or tapped with your finger. Our hands are how most of us interact with the digital world, but that isn’t an option for everyone, and [Shu Takahashi] wants to give them a new outlet to express themselves. Some folks who cannot use their hands will be able to use the Magpie MIDI, which acts as a keyboard, mouse, MIDI device, and eventually, a game controller. This universal Human Interface Device (HID) differs from a mouth-operated joystick because it has air pressure sensors instead of buttons. The sensors can recognize the difference between exhalation and inhalation, so the thirteen ports can be neutral, positive, or negative, which is like having twenty-six discrete buttons.

The harmonica mounts on an analog X-Y joystick to move a mouse pointer or manipulate MIDI sound like a whammy bar. [Shu] knows that a standard harmonica has ten ports, but he picked thirteen because all twenty-six letters are accessible by a puff or sip in keyboard mode. The inputs outnumber the Arduino Leonardo’s analog inputs, so there is a multiplexor to read all of them. There was not enough time to get an Arduino with enough native ports, like a Teensy, with HID support baked in. Most of the structure is 3D printed, so parts will be replaceable and maybe even customizable.

Even with two working hands, we like to exercise different hardware, but the harmonica is a nifty tool to have attached to your computer.

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Juuke – An RFID Music Player For Elderly And Kids

September 14, 2020 by Orlando Hoilett 15 Comments

[ananords] and his girlfriend wanted to make a simple and easy to use music player for her grandmother. Music players like CD players and MP3s have gotten just a bit too difficult to handle, so they wanted to find a much simpler solution.

They conceived the idea of creating a little jukebox called Juuk, with a simple and easy to use interface. They created individual RFID cards with the artist’s photo on the front face, making it easy to select different options from the music library. Juuk has a built-in RFID reader that will recognize each RFID card and play the appropriate musical number from an SD card.

This simple interface is much more user-friendly than those awful touchscreen devices that we’re all forced to fiddle with today and also has a cool retro appeal that many of our readers are sure to appreciate. Juuk also has a pretty ergonomic interface with a big, easy-to-use knob for controlling the volume and two appropriately illuminated buttons, one green and one red, for simple stop and play options.

We love when our hacks are able to blend form with function and emphasize high usability. Check out some of our other assistive tech on the blog.

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Olaf Lets An ESP32 Listen To The Music

August 30, 2020 by Al Williams 6 Comments

The joys of overengineering a simple gift. [Joren] wanted to create a dress for his daughter’s fourth birthday that would react with lights in sequence for a song from Frozen. The dress and an LED strip, along with a digital microphone and a battery were easy to procure. But how to make it all work? An ESP32 did the trick.

While the project’s name–Olaf–sounds like it was from Frozen, according to the GitHub page it actually means Overly Lightweight Acoustic Fingerprinting. Right. However, as the name implies, it can learn to identify any sound you want.

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Easy-To-Use Music Player Relies On RFID

August 29, 2020 by Lewin Day 17 Comments

Microwaves used to be simple to use. Set the dial for the desired time, and hit start. Then, everything went digital and the average microwave now takes between four and six button presses in precise order just to start heating. Music players have gone down a similar path, and those that grew up in the era of vinyl records can find modern digital media simply too hard to work with. To solve this problem, [ananords] whipped up Juuke, a music player focused on ease of use.

The Juuke has a simplistic interface intended to be as easy to use as possible. Songs are selected using printed cards with embedded RFID tags – placing them on the Juuke triggers playback. Volume is controlled with a simple knob, and the only two buttons are for play/pause and shuffle mode.

Underneath, an Arduino Uno runs the show, hooked up to a RC522 RFID interface board. Music is handled by the DFPlayer mini, which loads tracks off a microSD card. The DFPlayer can be hooked up to a speaker directly, but there’s also a 3.5mm jack output if the device is to be used with an external amplifier.

It’s a tidy project, and one that actually looks pretty fun to use. Obviously, there’s some time investment required to prepare the SD card and produce the RFID cards, but the final product could be fun to use at a party, too. We’ve seen similar builds before, as well. Video after the break.

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Slack Off From Home With A Networked Jam Session

August 26, 2020 by Kristina Panos 6 Comments

Those of you who were regular office dwellers before the pandemic: do you miss being with your coworkers at all? Maybe just a couple of them? There’s only so much fun you can have through a chat window or a videoconference. Even if you all happen to be musicians with instruments at the ready, your jam will likely be soured by latency issues.

[Eden Bar-Tov] and some fellow students had a better idea for breaking up the work-from-home monotony — a collaborative sequencer built for 2020 and beyond. Instead of everyone mashing buttons at once and hoping for the best, the group takes turns building up a melody. Each person is assigned a random instrument at the beginning, and the first to go is responsible for laying down the beat.

Inside each music box is an ESP8266 that communicates with a NodeRed server over MQTT, sending each melody as a string of digits. Before each person’s turn begins, the LED matrix shows a three second countdown, and then scrolls the current state of the song. Your turn is over when the LED strip around the edge goes crazy.

Music can be frustrating if you don’t know what you’re doing, but this instrument is built with the non-musician in mind. There are only five possible notes to play, and they’re always from the same scale to avoid dissonance. Loops are always in 4/4, which makes things easy. Players don’t even have to worry about staying in time, because their contributions are automatically matched to the beat. Check it out after the break.

Tired of sitting indoors all day, but still want to make music? Build a modular synth into a bike and you’ve solved two problems.

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