let gravity;

let position;

let acceleration;

let wind;

let drag = 0.99;

let mass = 50;

let potValue = 512;

let running = true;

​

function setup() {

  createCanvas(640, 360);

  noFill();

  position = createVector(width / 2, 0);

  velocity = createVector(0, 0);

  acceleration = createVector(0, 0);

  gravity = createVector(0, 0.5 * mass);

  wind = createVector(0, 0);

}

​

function draw() {

  background(255);

  //created this flag variable to get the ball to drop again

  if (!running) {

    textSize(24);

    fill(0);

    text("Press 's' to run again", width / 2 - 100, height / 2);

    return;

  }

  //mapping the value of the potentiometer to which direction the ball falls 

  wind.x = map(potValue, 0, 1023, -2.5, 2.5);

  applyForce(wind);

  applyForce(gravity);

  velocity.add(acceleration);

  velocity.mult(drag);

  position.add(velocity);

  acceleration.mult(0);

  ellipse(position.x, position.y, mass, mass);

  if (position.y > height - mass / 2) {

    velocity.y *= -0.9;

    position.y = height - mass / 2;

  //standard s

    if (serialActive) {

      writeSerial("Ball bounced\n");

      //sending this to arduino each time ball hits ground

    }

  }

  if (position.x < -mass || position.x > width + mass) {

    //preventing the ball from being registered when it rolls off the screen

    running = false;

  }

}

function applyForce(force) {

  let f = p5.Vector.div(force, mass);

  acceleration.add(f);

}

​

function keyPressed() {

  if (key == ' ') {

    //opening setup pop up window

    setUpSerial();

  }

​

  if (key == 's') {

    //preparing a new ball to drop resetting the values 

    fill('white');

    position = createVector(width / 2, 0);

    velocity = createVector(0, 0);

    acceleration = createVector(0, 0);

    running = true;

  }

}

function readSerial(data) {

  //just to avoid no readSerial error saving data

  if (data != null) {

    potValue = int(data);

  }

}

​