function setup() {

  createCanvas(400, 400);

  mic = new p5.AudioIn();

  mic.start(); // start mic

  noStroke();

  colorMode(HSB);

}

​

function draw() {

  //background(220, 220, 220, 10);

  background(255, 0, 0, 0.1);

  let diameter = mic.getLevel() * width;

  let hue = mic.getLevel() * 360;

  //let hue = map(mic.getLevel(), 0, 1, 0, 360);

  fill(hue, 100, 100, 0.5);

  circle(mouseX, mouseY, diameter);

}