What is multi?
multi is an open hardware circuit board hosting a Seeeduino XIAO, 6 pots, 2 pushbuttons, 2 Midi DIN connectors and an audio output.
The Seeeduino XIAO board carries the powerful ATSAMD21G18A-MU which is a low-power microcontroller and has 14 GPIO PINs, a DAC output and one UART interface. To avoid grounding loops the MIDI input is properly opto-isolated, as required by official specifications.
Bend multi to your needs
The strong point is that you can program your multi as you need, using the Arduino IDE.
On the MIDI side, possible use includes advanced midi controlling, filtering and remapping as well as algorithmic arpeggiators and aleatoric patch generators. It's also perfect to explore digital synthesis techniques.
Software
There are already several usable software and the list is constantly expanding:
- synth sequencer three oscillators monophonic synth with embedded sequencer. It receives MIDI clock and note messages
- drone it's a six oscillators drone machine
- euclidean sequencer receives midi clock, start/stop on the MIDI DIN input, generates euclidean rhythmes on the MIDI DIN output
- bytebeat player allows to play algorithmic music with no instruments and no real oscillators but a math expression that creates an audio output waveform as a function of time, processed 8000 times per second. The expression has six parameters accessible through the multi knobs
- fourier 3 voices drone generator, each voice is composed by six oscillators tuned on the harmonic overtones, each voice has six lfos
- cc scrambler generates random synthesizer patch by spitting out random MIDI CC values (preset fucker)
- multimode keep pressed PB1 and PB2 to choose the mode between: synth sequencer, drone, euclidean sequencer, bytebeat player, fourier and cc scrambler
- midi converter is a USB to 5 DIN bi-directional MIDI converter
- midi metronome takes the MIDI clock from the 5 DIN midi connector and generates a metronome click on the audio output, to allow acoustic musicians to synchronize their performance to an electronic setup
- hardware test if you have choosen the DIY kit you may want to use this software to test your build
- fm a simple fm synth
- blink the ubiquitous blink sketch
Compiling and uploading
To compile and upload the software on the Seeduino Xiao, you'll need:
- Arduino IDE
- MIDI library
- Mozzi library
- Adafruit TinyUSB Library for Arduino, install version 0.10.5 using the library manager
After installing all the required libraries, you must add the Seeeduino Xiao board to your Arduino IDE. Follow the instructions to get started on the SeeedStudio wiki.
Sound generation
Since the Xiao board has a DAC, multi can also be used to produce sounds using the Mozzi sonification library written by Tim Barrass or accessing directly to the DAC output.