​

function setup() {

  createCanvas(640, 480);

  textSize(18);

}

​

function draw() {

  background(255);

  fill(0);

​

  if (!serialActive) {

    text("Press Space Bar to select Serial Port", 20, 30);

  } else {

    text("Connected", 20, 30);

  }

  text("Brightness: "+str(brightness),width/2-50,height/2)

​

  if (keyIsPressed) {

    if (keyCode==UP_ARROW) {

      if (brightness<255){

        brightness+=5;

      }  

    } else if (keyCode==DOWN_ARROW) {

      if (brightness>0){

        brightness-=5;

      }

    }

  } 

}

​

function keyPressed() {

  if (key == " ") {

    // important to have in order to start the serial connection!!

    setUpSerial();

  }

}

​

function readSerial(data) {

  if (data != null) {

    writeSerial(brightness);

  }

}

​

​

​