import processing.serial.*;

Serial myPort;

// at the top of the program:
float xPos = 0; // horizontal position of the graph
float yPos = 0; // vertical position of the graph

void setup () {
  size(800, 600);        // window size
 
  // List all the available serial ports
  printArray(Serial.list());
  
// change the number below to match your port:
String portName = Serial.list()[11];
myPort = new Serial(this, portName, 9600);

background(#081640);

}

void serialEvent (Serial myPort) {
  // get the byte:
  int inByte = myPort.read();
  // print it:
  println(inByte);
  
  yPos = height - inByte;
}

void draw () {
  // draw the line in a pretty color:
  stroke(#A8D9A7);
  line(xPos, height, xPos, yPos);
  
  // at the edge of the screen, go back to the beginning:
if (xPos >= width) {
  xPos = 0;
  // clear the screen by resetting the background:
  background(#081640);
} else {
  // increment the horizontal position for the next reading:
  xPos++;
}

}