Hi, Im very new to this. Im trying to show a constant serial communication form a lightsensor via Arduino as constantly shifting percentage numbers in processing. Problem is the percentage is pretty wild and never goes to 0% or 100% ( I belive 50% is the max it has gone to) So I would like to hear with you guys if my code is wrong! if not I guess the serial communication is messed up. Here is the processing code:
The light sensor goes from 0 to 255, I used the Arduino calibration example if anyone is familiar with it.

1.     //import Serial communication library
2.     import processing.serial.*;
3.    
4.     //init variables
5.     Serial commPort;
6.  
7.     int lightread;
8.     double divide;
9.     float percent;
10.    
11.     PFont font12;
12.     PFont font24;
13.     void setup()
14.     {
15.       //setup fonts for use throughout the application
16.       font12 = loadFont("Arial-Black-24.vlw");
17.       font24 = loadFont("Arial-Black-48.vlw");
18.      
19.       //set the size of the window
20.       size(250, 200);
21.      
22.       //init serial communication port
23.         commPort = new Serial(this, Serial.list()[0], 9600);
24.      
25.     }
26.     void draw()
27.     {
28.       //get the ligtsensor value from the serial port
29.       while (commPort.available() > 0)
30.       {
31.         lightread = commPort.read();
32.        
33.         divide = lightread / 2.55;
34.        
35.         percent = ((float)divide) ; // divide 255 by 2,5 to get the percentage
36.     
37.   
38.         //refresh the background to clear old data
39.         background(123);  
40.        
41.         //Header
42.         fill(250,250,250);
43.         textFont(font12);
44.         textAlign(LEFT);
45.         text("Light percentage: ", 25, 25);
46.      
47.         //write the light in percentage
48.         fill(255,255,0);
49.         textFont(font24);
50.         textAlign(LEFT);
51.         text(str(int(percent)) + " %", 75, 75);
52.        
53.         // Show the serial communication in the terminal
54.         println(lightread);
55.       
56.       }
57.     }