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Topic: Error - Arduino to Processing - ArrayIndexOutOfBoundsException (Read 3862 times) previous topic - next topic



I am a beginner currently following the exercises in the Arduino starter kit. In the project 'Tweak the Arduino logo' I am getting the following error from the Processing bit:


Here's the Arduino code:

Code: [Select]
void setup() {

void loop() {

And this is the processing code:

Code: [Select]
import processing.serial.*;
Serial myPort;

PImage logo;

int bgcolor = 0; // change bg colour of the image

void setup() {
  colorMode(HSB, 255); // maximum value related to HSB

  logo = loadImage("http://arduino.cc/logo.png"); // download image
  size(logo.width, logo.height);

  println("Arduino serial ports");

  myPort =
    new Serial(this, Serial.list()[1411], 9600);

void draw() {
  if (myPort.available() > 0) {
    bgcolor = myPort.read();

  background(bgcolor, 255, 255);
  image(logo, 0, 0);

Has anyone experienced similar problem? How can I fix it?

Thanks in advance.


Your in the wrong part of the from you need "interfacing w/ software on the computer. Get a mod to move this post do not crosspost!

And add the rest of the error message you got.



Code: [Select]
    new Serial(this, Serial.list()[1411], 9600);the number in brackets is typically a number in the range of 0 to 5. 1411 is way out and the casue of your error.
The Serial.list[] is an array with all the com ports. Each element is just a string "COM1", "COM2*, "COM15" (or whatever you have on your machine, and it will something "/dev/tty" on a linux) and you can pas that string direct if you know your com port, like
Code: [Select]
new Serial(this, "COM15", 9600);


@Msquare thank you for your reply.

I am using a Macbook Pro and you're correct by assuming that my machine returns something like '/dev/tty'. For what I can understand from your explanation, the code should be something like this:

Code: [Select]
new Serial(this, "/dev/tty", 9600);

Is that correct?

I will try it tonight.

Thank you.


@holmes4 I have contacted the moderator.Thank you for the heads up.



Jul 25, 2013, 07:35 pm Last Edit: Jul 25, 2013, 07:43 pm by Msquare Reason: 1
Yes/no ---
Code: [Select]
println(Serial.list());prints a list of all the serial ports that are "active" on your machine.
The Serial.list()[n] is one of the strings, where n=0 is the first, n=1 is the second...
Now in your new Serial call, you can either use the Serial.list()[n] with the correct n-value or use that exact string inside "-quotes.

There is no need to use println(Serial.list());, once you know the port code "/dev/ttyb1" (or whatever yours is) which probably is fixed for a given connection.

(edits to fix a stupid formating error triggered by the processing syntax)

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