let lastVal = 0;

let smoothVal = 0;

let minVal = 1023;

let maxVal = 0;

​

function setup() {

  createCanvas(400, 400);

  port = createSerial();

}

​

function draw() {

  background(0);

  // unsmoothed

  noStroke();

  fill(255, 0, 0);

  ellipse(175, height - (lastVal - minVal) / (maxVal - minVal) * height, 25, 25);

  // smoothed

  fill(0, 0, 255);

  ellipse(225, height - (smoothVal - minVal) / (maxVal - minVal) * height, 25, 25);

  let received = port.readUntil("\n");

​

  if (received) {

    //console.log(received);

    lastVal = parseInt(received);

​

    // reject values that are either to low or too high

    // to be plausible

    if (99 < lastVal && lastVal < 1024) {

      if (lastVal < minVal) {

        minVal = lastVal;

        console.log('Saw new minimum value: ', minVal);

      }

      if (lastVal > maxVal) {

        maxVal = lastVal;

        console.log('Saw new maximum value: ', maxVal);

      }

      // general formula:

      smoothVal = smoothVal * 0.95 + lastVal * 0.05;

    }

  }

}

​

function mousePressed() {

  if (!port.opened()) {

    port.open('Arduino', 9600);

  }

}