Final Code

Here is our final arduino code:


#include <Stdio.h>

int xCoord;
int yCoord;
char coords[10];//Limits string to a certain number of characters

void setup()
{
  Serial.begin(9600);
}

void loop()
{
  xCoord = analogRead(0);
  yCoord = analogRead(1);
  sprintf(coords, "%d,%d", xCoord, yCoord);//creates the string "number,number"
  Serial.println(coords);//sends string to the serial port
  delay(50);//dalay the next string for 50 miliseconds

}

And our processing final code:


import processing.serial.*;

Serial myPort;
String buff = "";
String buff1 = "";
String buff2 = "";
int index = 0;
int NEWLINE = 10;

// Store the last 256 values received so we can graph them.
int[] valuesx = new int[1001];
int[] valuesy = new int[1001];

void setup()
{
  size(900, 900);
 
  println(Serial.list());

  String portName = Serial.list()[5];
  myPort = new Serial(this, portName, 9600);
 
  // If you know the name of the port used by the Arduino board, you
  // can specify it directly like this.
  //port = new Serial(this, "COM1", 9600);
 

}

void draw()
{
  background(0);
  stroke(255);
 
  // Graph the stored values by drawing a lines between them.
  for (int i = 0; i < 255; i++){
    stroke(i);
    strokeWeight(2);
    line(900 - valuesx[i], 900 - valuesy[i],900 - valuesx[i + 1],900 - valuesy[i + 1]);
  }
  while (myPort.available() > 0)
    serialEvent(myPort.read());
}

void serialEvent(int serial)
{
  if (serial != NEWLINE) {
    // Store all the characters on the line.
    buff += char(serial);
  }
  else {
    // The end of each line is marked by two characters, a carriage
    // return and a newline.  We're here because we've gotten a newline,
    // but we still need to strip off the carriage return.
   buff = buff.substring(0, buff.length()-1);
   index = buff.indexOf(",");
    buff1 = buff.substring(0, index);
    buff2 = buff.substring(index+1, buff.length());

    // Parse the String into an integer.  We divide by 4 because
    // analog inputs go from 0 to 1023 while colors in Processing
    // only go from 0 to 255.
    int x = Integer.parseInt(buff1)/2;
    int y = Integer.parseInt(buff2)/2;

    // Clear the value of "buff"
    buff = "";
   
    // Shift over the existing values to make room for the new one.
    for (int i = 0; i < 1000; i++)
    {
      valuesx[i] = valuesx[i + 1];
      valuesy[i] = valuesy[i + 1];
    }
   
    // Add the received value to the array.
    valuesx[555] = x;
    valuesy[555] = y;
  }
}

I pretty much completely understand what going on in the Arduino code but I don't entirely understand the processing code when it gets into the parsing information part.