I need help. Ive built a heartbeat sensor in Arduino and am now trying to visualize it in Processing. Below is an image of the Arduino input being visualized in Processing:

 

Now my problem is that the heartbeats are only vaguely depicted, so I need to find a way to "amplify" the peaks, so the heartbeats can be more easily read. Like this guy has done. If theres a need for more info or if you have any questions just ask! For more info on the project:  http://www.ddlab.dk/i-found-my-pulse/.

Below is the Processing Code I am using, its just a slight rewrite of the Basic Graphing Tutorial:

2. /*
3.  Graph
4.  A simple example of communication from the Arduino board to the computer:
5.  the value of analog input 0 is sent out the serial port.  We call this "serial"
6.  communication because the connection appears to both the Arduino and the
7.  computer as a serial port, even though it may actually use
8.  a USB cable. Bytes are sent one after another (serially) from the Arduino
9.  to the computer.
10.  You can use the Arduino serial monitor to view the sent data, or it can
11.  be read by Processing, PD, Max/MSP, or any other program capable of reading 
12.  data from a serial port.  The Processing code below graphs the data received 
13.  so you can see the value of the analog input changing over time.
14.  
15.  The circuit:
16.  Any analog input sensor is attached to analog in pin 0.
17.   
18.  created 2006
19.  by David A. Mellis
20.  modified 9 Apr 2012
21.  by Tom Igoe and Scott Fitzgerald
22.  
23.  This example code is in the public domain.
24. 
    
25.  http://www.arduino.cc/en/Tutorial/Graph
26.  */
27. 
    
28. import processing.serial.*;
29.  
30.  Serial myPort;        // The serial port
31.  int xPos = 1;         // horizontal position of the graph
32.  
33.  void setup () {
34.  // set the window size:
35.  size(1400, 500);      
36.  
37.  // List all the available serial ports
38.  println(Serial.list());
39.  // I know that the first port in the serial list on my mac
40.  // is always my  Arduino, so I open Serial.list()[0].
41.  // Open whatever port is the one you're using.
42.  myPort = new Serial(this, Serial.list()[0], 9600);
43.  // don't generate a serialEvent() unless you get a newline character:
44.  myPort.bufferUntil('\n');
45.  // set inital background:
46.  background(0);
47.  }
48.  void draw () {
49.  // everything happens in the serialEvent()
50.  }
51.  
52.  void serialEvent (Serial myPort) {
53.  // get the ASCII string:
54.  String inString = myPort.readStringUntil('\n');
55.  
56.  if (inString != null) {
57.  // trim off any whitespace:
58.  inString = trim(inString);
59.  // convert to an int and map to the screen height:
60.  float inByte = float(inString); 
61.  inByte = map(inByte, 0, 1023, 0, height);
62.  
63.  // draw the line:
64.  stroke(216, 24, 24);
65.  line(xPos, height, xPos, height - inByte);
66.  
67.  // at the edge of the screen, go back to the beginning:
68.  if (xPos >= width) {
69.  xPos = 0;
70.  background(0); 
71.  } 
72.  else {
73.  // increment the horizontal position:
74.  xPos++;
75.  }
76.  }
77.  }

Regards,

René