Mystrix app: Free-style Just Intonation

Inspiration

For obscure tuning systems, most people may not have the funds, skill and/or time to construct a made-to-task acoustic instrument. Worse, finding a controller is hard or downright impossible, and there may be differences in the tuning system architecture that would discourage repurposing a standard MIDI controller. Thus, we sought to make an application to demonstrate the flexibility software offers to enable developers to write software for more generalized controllers such as the grid-based Mystrix.

What it does

The controller sends out special System Exclusive (SysEx) MIDI messages according to the MIDI Tuning Standard (MTS) to retune compatible synthesizers to play in Free-style Just Intonation (FSJI) tuning.

How we built it

The Application uses the Matrix OS API on top of the Espressif ESP32-S3 microcontroller, which is compiled into a uf2 bootloader and flashed to the chip over USB-C.

Challenges we ran into

Setting up the toolchain to compile and export the software to the device provided some challenge, especially with the lack of documentation surrounding the Mystrix.

Accomplishments that we're proud of

A lot of polish was put into the project - the computational resources of the ESP32 inside the controller are limited, so some optimization had to be done to ensure per-frame and per-button press computations were minimal with the use of lookup tables that are constructed upon app launch.

What's next for Mystrix app: Free-style Just Intonation

Transposition of the grid-shaped UI, and extension of the 8x8 grid and modulation into other keys using other controllers.

Built With

• matrixos
• mts
• mystrix