Digital_Rectangle.pde

/*
A Processing sketch takes a digital input from the serial bus and uses it to scale a color a rectangle.
*/

import processing.serial.*; 

// this selects the port number for your computer. If the code has trouble, try
// changing this value to a number between 0 and 9
int portNum = 3;  // selects the port number 
 
Serial myPort;   // The serial port
String inVal;    // Input string from serial port
int lf = 10;     // ASCII linefeed 
int dataVal;

void setup() { 
  
  //sets the size of the canvas
  size(400,400);
  
  // prints out a list of all the serial ports connected to your computer and can
  // help with selecting the port number
  printArray(Serial.list());   

  // this code prepares the sketch to receive serial data
  myPort = new Serial(this, Serial.list()[portNum], 9600);
  myPort.bufferUntil(lf);
  
} 

 
void draw() {
  
  background(255);
  
  if(dataVal == 1) fill(255);
  else fill(0);

  rectMode(CENTER);
  rect(width/2,height/2,width/2,height/2);
  
} 

// this function will run automatically every time data is received.
void serialEvent(Serial p) { 
  
  //readString() reads the incoming serial data as a string.
  inVal = p.readString();
  
  //trim() takes the string it just received and trims off any word spaces or formatting
  inVal = trim(inVal);
  
  // int() converts the string to an integer
  dataVal = int(inVal);
  
}