var input = new Array(256);

var sampling_rate = 50;

var freq_step = 50/256;

var out = fft.createComplexArray();

​

var ble = new Orphe(0);

​

function setup() {

  // ORPHE CORE Init

  ble.setup();

  input.fill(0);

  ble.onStartNotify = function () {

    loop();

  };

  ble.gotAcc = function (_acc) {

    input.push(_acc.x);

    while (input.length > 256) {

      input.shift();

    }

  };

  createCanvas(20 + 256 + 20, 400);

  noLoop();

}

​

function draw() {

  background(200);

​

  if (input.length >= 256) {

    const data = fft.toComplexArray(input);

    fft.transform(out, data);

    noFill();

    beginShape();

    for (let i = 0; i < out.length / 2; i++) {

      text(i * freq_step, 20 + i, height - 10);

      vertex(20 + i, -pow(out[i], 2) + height - 20);

    }

    endShape();

​

    fill(0);

    textSize(7);

    textAlign(CENTER);

    for (let i = 0; i < out.length / 2; i += 25) {

      text((i * freq_step).toFixed(1), 20 + i, height - 10);

      line(20 + i, height - 18, 20 + i, height - 25);

    }

​

    text(`Frequency Step: ${freq_step}`, 10, 10);

  }

}

​