// 10-12-04 revised by Perry Hoberman for USC/CNTV/IM534 class to
// communicate with Basic Stamp 2 by writing the number 100
// to trigger input from the Stamp. Use with serialCableTest.bs2
// running on the Basic Stamp (which counts up and down between
// 0 and 400).

// Analog In 
// by Josh Nimoy <http://itp.jtnimoy.com>

// Reads a value from the serial port and sets the background color. 
// Running this example requires you have a BX-24 microcontroller
// and peripheral hardware. More information can be found on the tutorial 
// pages of Tom Igoe: http://stage.itp.nyu.edu/%7Etigoe/pcomp/examples.shtml
// Make sure to have the correct port selected in the "sketch" menu. Because 
// this program uses the serial port, it will not work within a web browser.
// Created 8 February 2003

String buff = ""; // serial input string
int val = 0;      // to convert serial input string to a number
int RETURN = 13;  // ASCII number for seperator (carriage return)
int data = 100;   // number to write to BS2 to trigger input

void setup()
{
  size(200, 200);     // window size
  beginSerial(9600); // open serial port
}

void loop()
{
  if (val <= 255) {
    background(val);         // set background color to current value
  } else {
    background(val-145,0,0); // if value is > 255, set background to a shade of red
  }
  
  if (buff == "");           // buff set to empty string after RETURN received
  {
    serialWrite(data);       // send a 100 to the BS2 to trigger new value
  }
}

void serialEvent() 
{ 
  // If the variable "serial" is not equal to the value for 
  // a new line, add the value to the variable "buff". If the 
  // value "serial" is equal to the value for a new line,
  //  save the value of the buffer into the variable "val".
  if(serial != RETURN) { 
    buff += char(serial);
  } else { 
    val = Integer.parseInt(buff); // Parse the String into an integer
    println(val);   
    buff = "";                    // Clear the value of "buff"
  }
}