example

/*
To use:
* Using the Arduino software, upload the StandardFirmata example (located
  in Examples > Firmata > StandardFirmata) to your Arduino board.
 
For more information, see: http://playground.arduino.cc/Interfacing/Processing
*/

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

Arduino arduino;


void setup() {
  size(470, 280);

  // Prints out the available serial ports.
  println(Arduino.list());
  
  // Modify this line, by changing the "0" to the index of the serial
  // port corresponding to your Arduino board (as it appears in the list
  // printed by the line above).
  arduino = new Arduino(this, Arduino.list()[0], 57600);
  
  // Alternatively, use the name of the serial port corresponding to your
  // Arduino (in double-quotes), as in the following line.
  //arduino = new Arduino(this, "/dev/tty.usbmodem621", 57600);
  
  // Set the Arduino digital pins as inputs.
  arduino.pinMode(0, Arduino.INPUT);
}

void draw() {  
  int potVal = arduino.analogRead(0);
  
  float colorVal = map(potVal, 0, 1023, 0, 255);
  println(colorVal);
  
  fill(colorVal, 127, 127);
  rect(0, 0, width, height);
}