Go Down

Topic: Processing not writing on a file (Read 293 times) previous topic - next topic


Good morning, I am trying to save some data that my arduino is getting and save it into a file, the problem is the processing is not writing into the file, the data is correct and the processing is getting the data perfectly, the only problem is when it has to write into the file. The file is also created perfectly but is empty, here is my processing code:

Code: [Select]

import processing.serial.Serial;
import java.util.Scanner;
Serial myPort;

PrintWriter myfile;
String arduinoString = "NoValueYet"; // text received from the Arduino
int arduinoInt = 0;
float arduinoFloat = 0.0;
// integer received from the Arduino
final color RED = color(255,0,0), GRAY = color(150), LIGHTGRAY = color(200);
color c = color(0);
int x = 0;
float y;

void setup() {
  printArray(Serial.list()); // print all port names
  String portName = Serial.list()[0];
  myPort = new Serial(this, portName, 9600);
  myfile = createWriter("data1.txt");

void draw() {
  /* storing data in myfile */
  /* visualizing data in the Processing display window */
  y = map(arduinoInt, 0, 1023, 0, height);
  line(x, height, x, height-y);
  x = x + 1;
  if (x >= width) {
    x = 0;

void serialEvent (Serial myPort) {
  String s = myPort.readStringUntil('\n');
  if (s != null) {
    Scanner scanner = new Scanner(s);
    if (scanner.hasNextInt()) {
      arduinoInt = scanner.nextInt();
      print(arduinoInt); // I added this file to check that the arduinoInt gets the value and it does
      myfile.print(arduinoString); // I added this to check if the problem is between serialEvent and draw, but is not, eventhough I add this line here the number is not saved in my file

    else if (scanner.hasNextFloat()) {
      arduinoFloat = scanner.nextFloat();
    else if (scanner.hasNext("RED") || scanner.hasNext("YELLOW") || scanner.hasNext("GREEN") ) {
      arduinoString = scanner.next();
  } // end of if-statement with condition (s != null)
void keyPressed() {
  myfile.flush(); // writes remaining data


the data is correct and the processing is getting the data perfectly
So, the Arduino is working perfectly. Good. That means that you don't have an Arduino problem.

This isn't the Processing forum.
The art of getting good answers lies in asking good questions.


You do have to close the file to update the FAT on FAT systems and maybe yours too.
1) http://gammon.com.au/blink  <-- tasking Arduino 1-2-3
2) http://gammon.com.au/serial <-- techniques howto
3) http://gammon.com.au/interrupts
Your sketch can sense ongoing process events in time.
Your sketch can make events to control it over time.

Go Up