Single pixel scanner with BlinkStick and webcam using Processing language

scanner.java

import blinkstick.*;
import processing.video.*;

Capture cam;

int width = 640;
int height = 480;

int rectSize = 20;

BlinkStick device;

void setup() {
  size(width, height);

  String[] cameras = Capture.list();
  
  if (cameras.length == 0) {
    println("There are no cameras available for capture.");
    exit();
  } else {
    println("Available cameras:");
    for (int i = 0; i < cameras.length; i++) {
      println(cameras[i]);
    }
    
    // The camera can be initialized directly using an 
    // element from the array returned by list():
    cam = new Capture(this, cameras[0]);
    cam.start();     
  }      
  
  device = BlinkStick.findFirst();
  
  if (device == null)
  {
    println("There are no BlinkSticks connected.");
  }
}

void draw() {
  if (cam.available() == true) {
    cam.read();

    image(cam, 0, 0);
    cam.loadPixels();
 
    fill(255, 255, 255, 0);
    double r = 0, g = 0, b = 0;

    int rectX = (width - rectSize) / 2;
    int rectY = (height - rectSize) / 2;
  
    rect(rectX, rectY, rectSize, rectSize);
    
    for (int x = rectX; x < rectX + rectSize; x++)
    {
      for (int y = rectY; y < rectY + rectSize; y++)
      {
        int p1 = cam.pixels[y * width + x];
        
        r += (p1 >>> 16) & 0xff;
        g += (p1 >>>  8) & 0xff;
        b +=  p1         & 0xff;
      }
    }
    
    int rr = (int)(r / rectSize / rectSize);
    int gg = (int)(g / rectSize / rectSize);
    int bb = (int)(b / rectSize / rectSize);
       
    if (device != null)
    {
      device.setColor(rr, gg, bb);    
    }
  }
}