Arduino + SuperCollider

// Author: Sebastian Grygiel (Sebi)
// Date: Spring 2015

// Demo video: https://www.youtube.com/watch?v=MJAmfSJmgrA
// See the Arduino script for more info: https://pastebin.com/yTEnXhfb
// Ask in youtube comments, although I haven't done much with Supercollider specifically
// Edit the COM port at the bottom of this file before use

( // For restarting
 SerialPort.closeAll;
 s.reboot;
)

( // Synth definition
SynthDef(\sinewave,{
    // key -> 49 == middle c
    // volume and mix take values of 0 to 1
    |key = 50, volume = 0, mix = 0.3|
    var freq = 440*pow(2,(key-49)/12);
    // Mix Sine and Saw using mix variable for ratios
    var output = Mix([SinOsc.ar(freq,0,volume*(1-mix)),Saw.ar(freq,volume*mix*0.8)]);
    Out.ar(0, [output, output]);
}).send(s);
)

// Create the synth
a = Synth(\sinewave);

(
// Open arduino link -- EDIT IN YOUR COM PORT PATH
p = ArduinoSMS("/dev/ttyUSB0", 115200);
p.action = {
    | ... msg |
    msg.postln;
    a.set(\volume, pow(min(1, msg[1]/200),2)/5);
    a.set(\mix,    pow(min(1,(msg[1] - 400)/600),2)/1.5);
    a.set(\key, msg[0]);
}
)