import processing.serial.*;
PrintWriter output;

Serial myPort;  // The serial port:

void setup() {
  // List all the available serial ports:
  println(Serial.list());
  myPort = new Serial(this, Serial.list()[0], 4800);
  
  // Create a new file in the sketch directory
   output = createWriter("data.txt"); 
}

void draw() {
     
  while (myPort.available() > 0) {
    String inBuffer = myPort.readString();   
    if (inBuffer != null) {
    print(inBuffer);
    output.print(inBuffer);
    }
  } 
   delay(10);
}  
 
 void keyPressed() {
  println("flush");   
  output.flush(); // Writes the remaining data to the file
  output.close(); // Finishes the file
  exit(); // Stops the program
}