Raspberry Pi Creates Melody

March 28, 2022 by Bryan Cockfield 2 Comments

For those who are not into prog rock in the 70s or old radio shows from the 40s, the Theremin may be an unfamiliar musical instrument. As a purely electronic device, it’s well outside the realm of conventional musical instruments. Two radio antennas detect the position of the musician’s hands to make a unique sound traditionally associated with eeriness or science fiction.

Normally a set of filters and amplifiers are used to build this instrument but this build instead replaces almost everything with a Raspberry Pi Zero 2, and instead of radio antennas to detect the position of the musician’s hands a set of two HC-SR04 distance sensors are used instead. With the processing power available from the Pi, the modernized instrument is able to output MIDI as well which makes this instrument easily able to interface with programs like GarageBand or any other MIDI-capable software.

The project build is split into two videos, the second of which is linked below. The project code is also available on the project’s GitHub page, so anyone with the Pi and other equipment available can easily start experimenting with this esoteric and often overlooked musical instrument. It’s been around for over 100 years now, and its offshoots (including this build) are as varied as the sounds they can produce.

Continue reading “Raspberry Pi Creates Melody” →

Rotary Phone MIDI Controller Still Makes Calls

March 15, 2022 by Kristina Panos 3 Comments

[Kevin] has long wanted to do something musical with a vintage rotary phone and an Arduino, and has finally done so and committed the first of several experiments to HTML in a five-part series. He found a nice old British Telecom number, but it had been converted to plug and socket wiring to work on the modern system. Because of this, [Kevin] wanted to keep it completely functional as a phone. After all, it ought to work fine until 2025, when pulse dialing will no longer be supported in [Kevin]’s locality.

As you can likely understand, [Kevin] was keen to interface with the phone from the outside and leave the inside untouched. He used a sacrificial ADSL filter’s PCB to break out the socket, and added a pull-up resistor between the pin and 5 V.

Pretty quickly, [Kevin] figured out that when the phone is on the hook, it gives a constant high signal, where as the picking up the phone presents as a high signal going low, and dialing each number results in pulses of that quantity that alternate between high and low. Continue reading “Rotary Phone MIDI Controller Still Makes Calls” →

Learn To Play Guitar, Digitally

March 2, 2022 by Bryan Cockfield 13 Comments

Learning to play a musical instrument takes a major time commitment. If you happened to be stuck inside your home at any point in the last two years, though, you may have had the opportunity that [Dmitriy] had to pick up a guitar and learn to play. Rather than stick with a traditional guitar, though, [Dmitriy] opted to build his own digital guitar which is packed with all kinds of features you won’t find in any Fender or Gibson.

The physical body of this unique instrument is entirely designed by [Dmitriy] out of 3D printed parts, and uses capacitive touch sensors for each of the notes on what would have been the guitar’s fretboard. The strings are also replaced with a set of six switches that can be strummed like a regular guitar, and are used to register when to play a note. After a few prototypes, everything was wired onto a custom PCB. The software side of this project is impressive as well; it involved creating custom firmware to register all of the button presses and transmit the information to a MIDI controller so that the guitar can communicate digitally with anything that supports MIDI.

To finish off the project, [Dmitriy] also added a wireless device as well as some other bonus features like an accelerometer, which can be used to augment the sound of the guitar in any way he can think of to program them. It’s one of the most innovative guitars we’ve seen since the prototype Noli smart guitar was unveiled last year, and this one is also on its way from prototype to market right now.

Continue reading “Learn To Play Guitar, Digitally” →

A Gameport Joystick To USB-MIDI Converter

February 24, 2022 by Lewin Day 1 Comment

These days, live music performance often involves electronic synthesizers and computers rather than traditional instruments played by hand. To aid in his own performances, [alekappa] built a special interface to take signals from a joystick and convert them to MIDI messages carried over USB.

The build is simple and straightforward, using a Teensy LC to interface with a simple gameport joystick. With a smattering of simple components, it’s easy to read the outputs of the joystick with only a little debounce code needed to ensure the joystick’s buttons are read accurately. Similarly, analog axes are read using the analog-to-digital converters onboard the microcontroller.

This data is then converted into control changes, note triggers and velocity levels and sent out over the Teensy LC’s USB interface. A mode switch enables changes to the system’s behaviour to be quickly made. The device is wrapped up in a convenient housing nabbed from an old Gameport-to-USB converter from many years ago.

It’s a neat project and we’re sure the joystick allows [alekappa] to add a new dimension to his performances on stage. We’ve seen other great MIDI controllers, too, from the knitted keyboard to the impressive Harmonicade. If you’ve got your own mad musical build under construction, don’t hesitate to drop us a line!

Sending MIDI Wirelessly With The NRF24L01

February 17, 2022 by Lewin Day 6 Comments

MIDI is a standard known by musicians and instruments all over the world. The basic twist on regular serial has helped studios around the world to work more efficiently. [Kevin] wanted to try sending MIDI data wirelessly, but rather than the typical Bluetooth solution, decided to use the humble nRF24L01 instead.

The circuitry used is simple: [Kevin] simply wired up two Arduino Unos with nRF24L01 radio modules, which communicate over SPI. Alternatively, an even quicker solution is to use a Keywish Arduino RF Nano, which packs a nRF24L01 on board. One Arduino can then be hooked up to a MIDI OUT port on an instrument, and it will send out MIDI signals wirelessly. The second Arduino can then be plugged into a MIDI IN port and repeat out what it receives over the air.

The real work was in the firmware, which takes MIDI data and packages it in a suitable form to send out over the nRF24L01. The system can operate in a one-to-one mode, emulating a single MIDI cable, or a multicast mode, where one sender transmits information to many receivers.

It’s a neat hack and one we could imagine would be useful in some fun performance situations. We’ve seen others do work on wireless MIDI interfaces for Eurorack hardware, too. Video after the break.

Continue reading “Sending MIDI Wirelessly With The NRF24L01” →

You Can Send MIDI Over I2C If You Really Need To

February 15, 2022 by Lewin Day 11 Comments

The Musical Instrument Digital Interface has a great acronym that is both nice to say and cleanly descriptive. The standard for talking to musical instruments relies on a serial signal at 31250 bps, which makes it easy to transmit using any old microcontroller UART with a settable baud rate. However, [Kevin] has dived into explore the utility of sending MIDI signals over I2C instead.

With a bit of hacking at the Arduino MIDI library, [Kevin] was able to get the microcontroller outputting MIDI data over the I2C interface, and developed a useful generic I2C MIDI transport for the platform. His first tests involved using this technique in concert with Gravity dual UART modules. After he successfully got one running, [Kevin] realised that four could be hooked up to a single Arduino, giving it 8 serial UARTS, or, in another way of thinking, 8 MIDI outputs.

At its greatest level of development, [Kevin] shows off his I2C MIDI chops by getting a single Raspberry Pi Pico delivering MIDI signals to 8 Arduinos, all over I2C. All the Arduinos are daisy-chained with their 5V and I2C lines wired together, and the system basically swaps out traditional MIDI channels for I2C addresses instead.

There’s not a whole lot of obvious killer applications for this, but if you want to send MIDI data to a bunch of microcontrollers, you might find it easier daisy-chaining I2C rather than hopping around with a serial line in the classic MIDI-IN/MIDI-THRU fashion.

We’ve seen [Kevin]’s work before too, like the wonderful Lo-Fi Orchestra. Video after the break.

Continue reading “You Can Send MIDI Over I2C If You Really Need To” →

Artist operating artistic visualizer with MIDI keyboard

Synth And Visualizer Combo Has Retrocomputing Vibe

January 11, 2022 by Donald Papp 7 Comments

[Love Hultén]’s latest piece of interactive art is the SYNTH#BOI, a super-clean build with something of the semi-cyberdeck, semi-vintage computing vibe to it. The device is a combination synthesizer and visualizer, with a 15-inch display, MIDI keyboard, and based on an Intel NUC i5 small form factor PC.

There are not many details about the internal workings of the device, but the high quality of the build is very evident. Photos show a fantastic-looking enclosure with clean lines and sharp finish; it’s a reminder that careful measuring and attention to detail can be the difference between something that looks like a hack job, and something that looks like a finished product.

Watch the SYNTH#BOI in action in the video, embedded below. And if the name [Love Hultén] seems familiar, it’s probably because we featured his VOC-25 “Pink Denture Synth”, a concept instrument with a decidedly memorable design of its own.

Continue reading “Synth And Visualizer Combo Has Retrocomputing Vibe” →