Hi there,

I think to do this you will need to use objects, you will have to create a ball object which has an x and y value and a function which moves it along the screen and draws the ellipse.

It would look something like this -

class Ball {

      //these variables hold the position the ball is on the window and how big it is
      int x,y, ellipseHeight, ellipseWidth;

      //this is the constructor used to create a new ball object
      Ball(int xval, yval, eheight, ewidth) {

            x = xval;
            y = yval;
            ellipseHeight = eheight;
            ellipseWidth = ewidth;
      }

      //this function moves the ball
      void moveBall(int moveX, moveY) {
            x+=moveX;
            y+=moveY;
      }

      //this function draws the ball
      void drawBall() {
            ellipse(x,y,ellipseWidth, ellipseHeight);
      }
}

You can then create an object for each of the balls you need on the screen like so.

Ball sphere1dropper = new Ball(45,0,30,30)

then in the draw() function you can move the ball and redraw it, like so.

background(0);
sphere1dropper.moveBall(0,10)
shpere1dopper.drawBall();

you can also then check where the ball is by doing somethiing like this:

if (sphere1dropper.y < 300) {
      //do something
else
      //do something else

There is some more information about using objects here:
http://processing.org/learning/objects/

I hope this helps.

Thanks A LOT for your reply, I think im getting somewhere but now i get this 'easy to fix' NullPointerException, sorry but i cant fix it :( 

You need to remove the Ball from lines 27-31 so that it looks like this:

Sphere1dropper = new Ball(45,0,30,30); 

The way it was before meant that it couldn't be seen in the draw function.

Ok, NullPointerException is gone, and i gave my new Ball's the right stroke/fill but i dont see anything falling :P? 

It's probably to do with where you are doing background(0).

I can remove the track by putting background(0); at the top of the draw but for the computer the track will still be there but i can't see it. That would be fine but since i want to check if the falling ball is in a certain margin below to send info to my arduino this doesnt work. Because the track is still their the signal will be send all the time after the first ball passed the checkbox below

Ofcourse, I already started with the Balls for the whole game so dont look at the droppers14 - 26. 

Using it again doesnt matter anymore because I already made all the balls. About the track, I think i know what you mean but i have no clue have to do it.... Tried to put background(0) above every drawBall statement but that didnt work.

You have already done it, I made a video using your code which might make it clearer, the only change I made was the line that writes to the arduino, instead of sending a signal I put an ellipse on the screen to represent the time that the signal would be sent.



www.youtube.com/watch?v=KiEdo04gapA

Ok, but in my arduino code it says this:

Unfortunately I've not done anything with the Arduino, do you need to clear what was written to the pin before you can write again?

Ok, Thanks for all your help with my processing sketch. I really really appreciate it that you spended some time to help me out!

Huh i tried to do the same as you did in the video, but i see no ellipse when the ball is in the checkbox. 

I replaced port.write(1); in your code with an ellipse.

Can u post that code because when i add ellipse(45,450,30,30) with some color it doesnt show up. Even if i use a new draw Ball it doesnt.... Facepalm!

Here you are.

import processing.serial.*;

Serial port;

int xval;
int yval;
int eheight;
int ewidth;
int moveX;
int moveY;
Ball Sphere1dropper;
Ball Sphere2dropper;
Ball Sphere3dropper;
Ball Sphere4dropper;
Ball Sphere5dropper;
Ball Sphere6dropper;
Ball Sphere7dropper;
Ball Sphere8dropper;
Ball Sphere9dropper;
Ball Sphere10dropper;
Ball Sphere11dropper;
Ball Sphere12dropper;
Ball Sphere13dropper;
Ball Sphere14dropper;
Ball Sphere15dropper;
Ball Sphere16dropper;
Ball Sphere17dropper;
Ball Sphere18dropper;
Ball Sphere19dropper;
Ball Sphere20dropper;
Ball Sphere21dropper;
Ball Sphere22dropper;
Ball Sphere23dropper;
Ball Sphere24dropper;
Ball Sphere25dropper;
Ball Sphere26dropper;


void setup(){
  size(450,1000);
  background(0);
  smooth();
 
  //String portName = Serial.list()[0];
  //port = new Serial(this, portName, 9600);
 
  Sphere1dropper = new Ball(45,-250,30,30);
  Sphere2dropper = new Ball(135,-500,30,30);
  Sphere3dropper = new Ball(225,-750,30,30);
  Sphere4dropper = new Ball(315,-1000,30,30);
  Sphere5dropper = new Ball(405,-1250,30,30);
  Sphere6dropper = new Ball(45, -1500, 30, 30);
  Sphere7dropper = new Ball(135,-1750, 30, 30);
  Sphere8dropper = new Ball(225,-2000, 30, 30);
  Sphere9dropper = new Ball(315,-2250, 30, 30);
  Sphere10dropper = new Ball(405,-2500, 30, 30);
  Sphere11dropper = new Ball(405,-2750, 30, 30);
  Sphere12dropper = new Ball(225,-3000, 30, 30);
  Sphere13dropper = new Ball(45,-3250, 30, 30);
  Sphere14dropper = new Ball(405,-2500, 30, 30);
  Sphere15dropper = new Ball(405,-2500, 30, 30);
  Sphere16dropper = new Ball(405,-2500, 30, 30);
  Sphere17dropper = new Ball(405,-2500, 30, 30);
  Sphere18dropper = new Ball(405,-2500, 30, 30);
  Sphere19dropper = new Ball(405,-2500, 30, 30);
  Sphere20dropper = new Ball(405,-2500, 30, 30);
  Sphere21dropper = new Ball(405,-2500, 30, 30);
  Sphere22dropper = new Ball(405,-2500, 30, 30);
  Sphere23dropper = new Ball(405,-2500, 30, 30);
  Sphere24dropper = new Ball(405,-2500, 30, 30);
  Sphere25dropper = new Ball(405,-2500, 30, 30);
  Sphere26dropper = new Ball(405,-2500, 30, 30);
 
  }



void draw(){
 
  background(0);
  send_info_to_arduino();
  stroke(51,204,0);  // 1st
  fill(51,204,0);
  Sphere1dropper.moveBall(0,5);
  Sphere1dropper.drawBall(); 
 
  Sphere6dropper.moveBall(0,5);
  Sphere6dropper.drawBall();
 
  Sphere13dropper.moveBall(0,5);
  Sphere13dropper.drawBall();
 
  stroke(255,0,0);  // 2nd
  fill(255,0,0);
  Sphere2dropper.moveBall(0,5);
  Sphere2dropper.drawBall();
 
  Sphere7dropper.moveBall(0,5);
  Sphere7dropper.drawBall();
 
  stroke(255,255,0);  // 3th
  fill(255,255,0); 
  Sphere3dropper.moveBall(0,5);
  Sphere3dropper.drawBall();
 
  Sphere8dropper.moveBall(0,5);
  Sphere8dropper.drawBall();
 
  Sphere12dropper.moveBall(0,5);
  Sphere12dropper.drawBall();
 
  stroke(0,0,255);  // 4th
  fill(0,0,255);
  Sphere4dropper.moveBall(0,5);
  Sphere4dropper.drawBall();
 
  Sphere9dropper.moveBall(0,5);
  Sphere9dropper.drawBall();
 
  stroke(153,102,0); // 5th
  fill(153,102,0);
  Sphere5dropper.moveBall(0,5);
  Sphere5dropper.drawBall();

  Sphere10dropper.moveBall(0,5);
  Sphere10dropper.drawBall();
 
  Sphere11dropper.moveBall(0,5);
  Sphere11dropper.drawBall();
 
 //these two shapes are the background
 beginShape();
 stroke(255);
 strokeWeight(1);
 line(90, 0, 90, 1900);
 line(180, 0, 180, 1900);
 line(270, 0, 270, 1900);
 line(360, 0, 360, 1900);
 line(0, 250, 450, 250);
 line(0, 500, 450, 500);
 line(0, 750, 450, 750);
 line(0, 1000, 450, 1000);
 endShape();

 beginShape();
 noFill();
 strokeWeight(2);
 stroke(51,204,0);
 ellipse(45, 875, 45, 45);
 stroke(255,0,0);
 ellipse(135, 875, 45, 45);
 stroke(255,255,0);
 ellipse(225, 875, 45, 45);
 stroke(0,0,255);
 ellipse(315, 875, 45, 45);
 stroke(153,102,0);
 ellipse(405, 875, 45, 45);
 endShape();
 
}

class Ball {

      //these variables hold the position the ball is on the window and how big it is
      int x;
      int y;
      int ellipseHeight;
      int ellipseWidth;

      //this is the constructor used to create a new ball object
      Ball(int xval, int yval, int eheight, int ewidth) {
            x = xval;
            y = yval;
            ellipseHeight = eheight;
            ellipseWidth = ewidth;
      }

      //this function draws the ball
      void drawBall() {
            ellipse(x,y,ellipseWidth, ellipseHeight);
            }
           
          
           
      //this function moves the ball
      void moveBall(int moveX, int moveY) {
            x+=moveX;
            y+=moveY;
      }
}

void send_info_to_arduino()
    {
      if (Sphere1dropper.y > 850 && Sphere1dropper.y < 900){
        //port.write(1);
        ellipse(45, 475, 45, 45);
      }
      if (Sphere2dropper.y > 850 && Sphere2dropper.y < 900){
        //port.write(1);
        ellipse(135, 475, 45, 45);
        }
      if (Sphere3dropper.y > 850 && Sphere3dropper.y < 900){
        ellipse(225, 475, 45, 45);
        //port.write(1);
      }
      if (Sphere4dropper.y > 850 && Sphere4dropper.y < 900){
        ellipse(315, 475, 45, 45);
        //port.write(1);
      }
      if (Sphere5dropper.y > 850 && Sphere5dropper.y < 900){
        ellipse(405, 475, 45, 45);
        //port.write(1);
      }
     
    }import processing.serial.*;

Serial port;

int xval;
int yval;
int eheight;
int ewidth;
int moveX;
int moveY;
Ball Sphere1dropper;
Ball Sphere2dropper;
Ball Sphere3dropper;
Ball Sphere4dropper;
Ball Sphere5dropper;
Ball Sphere6dropper;
Ball Sphere7dropper;
Ball Sphere8dropper;
Ball Sphere9dropper;
Ball Sphere10dropper;
Ball Sphere11dropper;
Ball Sphere12dropper;
Ball Sphere13dropper;
Ball Sphere14dropper;
Ball Sphere15dropper;
Ball Sphere16dropper;
Ball Sphere17dropper;
Ball Sphere18dropper;
Ball Sphere19dropper;
Ball Sphere20dropper;
Ball Sphere21dropper;
Ball Sphere22dropper;
Ball Sphere23dropper;
Ball Sphere24dropper;
Ball Sphere25dropper;
Ball Sphere26dropper;


void setup(){
  size(450,1000);
  background(0);
  smooth();
 
  //String portName = Serial.list()[0];
  //port = new Serial(this, portName, 9600);
 
  Sphere1dropper = new Ball(45,-250,30,30);
  Sphere2dropper = new Ball(135,-500,30,30);
  Sphere3dropper = new Ball(225,-750,30,30);
  Sphere4dropper = new Ball(315,-1000,30,30);
  Sphere5dropper = new Ball(405,-1250,30,30);
  Sphere6dropper = new Ball(45, -1500, 30, 30);
  Sphere7dropper = new Ball(135,-1750, 30, 30);
  Sphere8dropper = new Ball(225,-2000, 30, 30);
  Sphere9dropper = new Ball(315,-2250, 30, 30);
  Sphere10dropper = new Ball(405,-2500, 30, 30);
  Sphere11dropper = new Ball(405,-2750, 30, 30);
  Sphere12dropper = new Ball(225,-3000, 30, 30);
  Sphere13dropper = new Ball(45,-3250, 30, 30);
  Sphere14dropper = new Ball(405,-2500, 30, 30);
  Sphere15dropper = new Ball(405,-2500, 30, 30);
  Sphere16dropper = new Ball(405,-2500, 30, 30);
  Sphere17dropper = new Ball(405,-2500, 30, 30);
  Sphere18dropper = new Ball(405,-2500, 30, 30);
  Sphere19dropper = new Ball(405,-2500, 30, 30);
  Sphere20dropper = new Ball(405,-2500, 30, 30);
  Sphere21dropper = new Ball(405,-2500, 30, 30);
  Sphere22dropper = new Ball(405,-2500, 30, 30);
  Sphere23dropper = new Ball(405,-2500, 30, 30);
  Sphere24dropper = new Ball(405,-2500, 30, 30);
  Sphere25dropper = new Ball(405,-2500, 30, 30);
  Sphere26dropper = new Ball(405,-2500, 30, 30);
 
  }



void draw(){
 
  background(0);
  send_info_to_arduino();
  stroke(51,204,0);  // 1st
  fill(51,204,0);
  Sphere1dropper.moveBall(0,5);
  Sphere1dropper.drawBall();
  if (Sphere1dropper.y > 1000) {
     Sphere1dropper.y = 0;
  } 
 
  Sphere6dropper.moveBall(0,5);
  Sphere6dropper.drawBall();
 
  Sphere13dropper.moveBall(0,5);
  Sphere13dropper.drawBall();
 
  stroke(255,0,0);  // 2nd
  fill(255,0,0);
  Sphere2dropper.moveBall(0,5);
  Sphere2dropper.drawBall();
 
  Sphere7dropper.moveBall(0,5);
  Sphere7dropper.drawBall();
 
  stroke(255,255,0);  // 3th
  fill(255,255,0); 
  Sphere3dropper.moveBall(0,5);
  Sphere3dropper.drawBall();
 
  Sphere8dropper.moveBall(0,5);
  Sphere8dropper.drawBall();
 
  Sphere12dropper.moveBall(0,5);
  Sphere12dropper.drawBall();
 
  stroke(0,0,255);  // 4th
  fill(0,0,255);
  Sphere4dropper.moveBall(0,5);
  Sphere4dropper.drawBall();
 
  Sphere9dropper.moveBall(0,5);
  Sphere9dropper.drawBall();
 
  stroke(153,102,0); // 5th
  fill(153,102,0);
  Sphere5dropper.moveBall(0,5);
  Sphere5dropper.drawBall();

  Sphere10dropper.moveBall(0,5);
  Sphere10dropper.drawBall();
 
  Sphere11dropper.moveBall(0,5);
  Sphere11dropper.drawBall();
 
 //these two shapes are the background
 beginShape();
 stroke(255);
 strokeWeight(1);
 line(90, 0, 90, 1900);
 line(180, 0, 180, 1900);
 line(270, 0, 270, 1900);
 line(360, 0, 360, 1900);
 line(0, 250, 450, 250);
 line(0, 500, 450, 500);
 line(0, 750, 450, 750);
 line(0, 1000, 450, 1000);
 endShape();

 beginShape();
 noFill();
 strokeWeight(2);
 stroke(51,204,0);
 ellipse(45, 875, 45, 45);
 stroke(255,0,0);
 ellipse(135, 875, 45, 45);
 stroke(255,255,0);
 ellipse(225, 875, 45, 45);
 stroke(0,0,255);
 ellipse(315, 875, 45, 45);
 stroke(153,102,0);
 ellipse(405, 875, 45, 45);
 endShape();
 
}

class Ball {

      //these variables hold the position the ball is on the window and how big it is
      int x;
      int y;
      int ellipseHeight;
      int ellipseWidth;

      //this is the constructor used to create a new ball object
      Ball(int xval, int yval, int eheight, int ewidth) {
            x = xval;
            y = yval;
            ellipseHeight = eheight;
            ellipseWidth = ewidth;
      }

      //this function draws the ball
      void drawBall() {
            ellipse(x,y,ellipseWidth, ellipseHeight);
            }
           
          
           
      //this function moves the ball
      void moveBall(int moveX, int moveY) {
            x+=moveX;
            y+=moveY;
      }
}

void send_info_to_arduino()
    {
      if (Sphere1dropper.y > 850 && Sphere1dropper.y < 900){
        print("port.write(1); " + Sphere1dropper.y + " ");
        ellipse(45, 475, 45, 45);
      }
      if (Sphere2dropper.y > 850 && Sphere2dropper.y < 900){
        ellipse(45, 475, 45, 45);
        print("port.write(2);");
      }
      /*
      if (Sphere3dropper.y > 850 && Sphere3dropper.y < 900){
        port.write(1);
      }
      if (Sphere4dropper.y > 850 && Sphere4dropper.y < 900){
        port.write(1);
      }
      if (Sphere5dropper.y > 850 && Sphere5dropper.y < 900){
        port.write(1);
      }
      */
    }

From what I see, you might be interested by the article: From several variables to arrays