Have u tried reseting the arduino just before starting the processing program?

i just posted this somewhere else, but i guess it could help to post again?

I use
http://www.arduino.cc/playground/Interfacing/Firmata
to get values via serial port - don't forget to adjust the serial port values in the Firmata processing scripts to get the right one

I just posted:
http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Exhibition;acti on=display;num=1213500039

maybe it'll help? =] - lemme know if you have questions

best of luck,
-Jeff

Quoted from http://www.arduino.cc/playground/Interfacing/Processing

//Start Quote:

Arduino Library for Processing (and Firmata)

There's a Processing library that works with Firmata (a standard Arduino firmware that works with lots of software).

Download

processing-arduino.zip (http://www.arduino.cc/playground/uploads/Interfacing/processing-arduino.zip)

Instructions

  1. Unzip the library and copy the "arduino" folder into the "libraries" sub-folder of the Processing application directory.
  2. Open the firmware (in arduino/firmware) in Arduino and upload it to the Arduino board.
  3. Configure Processing for serial: http://processing.org/reference/libraries/serial/
  4. In Processing, open one of the examples that comes with with the Arduino library.
  5. Edit the example code to select the correct serial port.
  6. Run the example.

//End Quote


I'd say the most tricky part is step #5 where you pick the correct COM port - basically, you pick the same COM port you use to program your arduino

under the setup() in every example is a line that reads:
 arduino = new Arduino(this, Arduino.list()[X], 57600);

Where X is a number - unfortunately, this is kind of confusing because the X isn't just COM port number X, but is based on the list Arduino.list() - to figure out the mapping, run this in processing:

//START CODE

import processing.serial.*;
import cc.arduino.*;
println(Arduino.list());

//END CODE

in the CLI on the bottom, you should see something like:



Stable Library
=========================================
Native lib Version = RXTX-2.1-7
Java lib Version   = RXTX-2.1-7
[0] "COM1"
[1] "COM4"
[2] "COM5"
[3] "COM6"
[4] "COM7"
[5] "COM8"
[6] "COM9"
[7] "COM10"
[8] "COM11"
[9] "COM12"

the COM port you want should correspond to the array index and that is your X value that you fill in the
 arduino = new Arduino(this, Arduino.list()[X], 57600);
line

i hope that helps =]

as for the "rules" for the library - i'd read:
http://www.arduino.cc/playground/Interfacing/Processing
which is basically the article i used - there's a really good reference section there too

perhaps I didn't explain it well enough =/

The way I'm introducing is really different from the previous way you were doing it (I find this easier because I'm more of a software person than a hardware person)

The Arduino should have the firmata sketch loaded. To do this, download:
http://www.arduino.cc/playground/uploads/Interfacing/processing-arduino. zip
and unextract it.

In the arduino IDE, open the file in the path arduino/firmware/Standard_Firmata/Standard_Firmata.pde

Now upload this sketch to your Arduino board. Basically, the Firmata sketch allows processing to access the Arduino board over the serial bus and query the digital/analog sensors (among another things).

-That's it for the Arduino programming - nothing left to do with the Arduino.

Now on the processing side, try this sketch (I just tested it and it seems to work):

Code:

import processing.serial.*;
import cc.arduino.*;

int analogPin = 5;
int analogValue = 0;

Arduino arduino;

void setup(){
	  println(arduino.list());
  arduino = new Arduino(this, Arduino.list()[1], 57600);
}

void draw(){
analogValue = arduino.analogRead(analogPin);
int inByte = int(map(analogValue,0,1023,0,255));  //I'm mapping the analogSensor values (0-1023) to values between 0-255 like you originally wanted =]
println(inByte);
}
 

I tried to preserve the variable names you used in your previous example - I tested this with a potentiometer hooked up to analog input 5 on the arduino and it worked just fine.

Lemme know how that works for you =] - hope it helps

cheers,
-Jeff

PS: in the arduino script in your .png, you have a line that reads:
analogValue = analogValue / 0.39
why is that? analogRead() returns 10-bit resolution values between 0-1023, so wouldn't dividing by 0.39 map your values between 0-2623 instead of 0-256 like you want?

EDIT: figured out how to use the CODE tags =]

perhaps try serialEvent() and see if that does anything?

http://processing.org/reference/libraries/serial/serialEvent_.html

I normally just stick to Firmata, so this is out of my league, sorry =/