Fast Serial Saving Data from Arduino

Core Library Questions

barekatf

Fast Serial Saving Data from Arduino

in Core Library Questions • 11 months ago

Hello,

I need to save incoming data from Arduino sent in this format at a serial speed of 57600:
The data are all int type.

    Serial.print(drive, DEC);
    Serial.print(" ");
    Serial.print(distanceAry[index], DEC);
    Serial.print(" ");
    Serial.print(pressureAry[index], DEC);
    Serial.print(" ");
    Serial.print(prSwitchAry[index], DEC);
    Serial.print(" ");
    Serial.println(tempAry[index], DEC);

Here is my processing program:

import processing.serial.*;
PrintWriter output;
Serial myPort;
String myData = null;
String[] Data = new String[5000];
int numData = 0;
int n = 0;
int m = 0;
void setup() {
println(Serial.list());
String portName = Serial.list()[0];
// change [0] for the Arduino serial port
myPort = new Serial(this, "COM5", 57600);
myPort.bufferUntil('\n'); // SerialEvent for new line
myPort.clear();
String Name = "Data "+str(month())+"-"+str(day())+"-"+str(year())
    +"_"+str(hour())+"."+str(minute())+".txt";
// Create file to save the captured data
output = createWriter(Name);
}

void draw() {
while ( myPort.available () > 0 ) {
    myData = myPort.readStringUntil('\n');
    if ( myData != null ) {
      Data[n] = myData;
      n++;
    }
}
while ( myPort.available() <= 0) {
    if ( Data[m] != null) {
      output.print(Data[m]);
      m++;
    }
}
}
void keyPressed() {
output.flush(); // Writes the remaining data to the file
output.close(); // Finishes the file
exit(); // Stops the program
}

The Arduino sends data when a push button is activated and it sends the data described above for 3.1 seconds. The data in the arrays was captured every 5 ms. (200Hz). The total number of data sequence is 620 rows and in each row there are 5 data.
Here is the problem I have:
First I run the processing program, then I press the push button. The TX light is on for a short time (~3.1 seconds).
Now my code says, if I press any key on keyboard, flush/close the file, and terminate the program, right?... This does not work, and I have to stop the program by clicking the Stop Button in the processing window.
Here is the weird thing: After I close the program, I only have 2.8 seconds of data in the output file. where did the other 300 ms go?
I really appreciate it if you can help me understand this, or you have some idea on how to fix this.
Thanks

Replies(6)

PhiLho

Re: Fast Serial Saving Data from Arduino

11 months ago

In draw(), you loop while you have data available, then you loop while no data is available.
You should exit draw() after the writing is finished. Otherwise, you are mostly stuck in draw(), so I suppose keyPressed() hasn't the time to be called (although it is supposed to be asynchronous?). Worth a try, at least.

barekatf

Re: Fast Serial Saving Data from Arduino

11 months ago

Hi PhiLho,

So you are saying I put the exit() in the loop of not having data?
In that case draw() will exit immediately right after i begin the program...

Is there a way to tell draw to exit if I dont have data for 10 seconds?

Thanks

PhiLho

Re: Fast Serial Saving Data from Arduino

11 months ago

I wrote "you should exit draw()", not "you should call exit() in draw()"...
By "exit draw()", I mean just let the function return, reaching its end.
Don't forget that draw() is called 60 times per second, as long as the sketch runs.

barekatf

Re: Fast Serial Saving Data from Arduino

11 months ago

Thanks PhiLho for your response.

Please help me understand this. I am running the processing program, Then I press a button on the arduino circuit to initialize the data sending. After 3.1 sec the data stream ends. Now what I want to do is to exit the processing program automatically after the data sending has finished.

Could you create some example code?

Thanks

PhiLho

Re: Fast Serial Saving Data from Arduino

11 months ago

Ah, so you really want to exit at the end. So, you don't end with a key pressed, then.

" Could you create some example code?"
Hardly, as I have no serial device, so I cannot test. But perhaps what you want is something like:

void draw() {
while ( myPort.available () > 0 ) {
myData = myPort.readStringUntil('\n');
if ( myData != null ) {
Data[n] = myData;
n++;
}
}
while (m < n) {
output.print(Data[m]);
m++;
}
output.flush(); // Writes the remaining data to the file (actually, close() do the flush()).
output.close(); // Finishes the file
exit(); // Stops the program
}

Alternatively, you can write directly to output:

void draw() {
while ( myPort.available () > 0 ) {
myData = myPort.readStringUntil('\n');
if ( myData != null ) {
output.print(myData);
}
}
output.flush(); // Writes the remaining data to the file (actually, close() do the flush()).
output.close(); // Finishes the file
exit(); // Stops the program
}

barekatf

Re: Fast Serial Saving Data from Arduino

11 months ago

Hi PhiLho,

I figured it out. Your code gave me some ideas on how to do it. Here is the result:

import processing.serial.*;
PrintWriter output;
Serial myPort;
String myData = null;
String[] Data = new String[5000];
int n = 0;
int m = 0;

void setup() {
println(Serial.list());
String portName = Serial.list()[0];
// change [0] for the Arduino serial port
myPort = new Serial(this, "COM5", 57600);
myPort.bufferUntil('\n'); // SerialEvent for new line
myPort.clear();
String Name = "Data "+str(month())+"-"+str(day())+"-"+str(year())
    +"_"+str(hour())+"."+str(minute())+".txt";
// Create file to save the captured data
output = createWriter(Name);
}

void draw() {
while ( myPort.available () > 0 ) {
    myData = myPort.readStringUntil('\n');
    if ( myData != null ) {
      Data[n] = myData;
      n++;
    }
}
while (m < n) {
    if ( Data[m] != null) {
      output.print(Data[m]);
      m++;
    }
}
if ( m == n ) {
    if ( m >= 620 ) { // number of data lines in 3.1 seconds.
      output.flush(); // Writes the remaining data to the file
      output.close(); // Finishes the file
      exit(); // Stops the program
    }
}
}

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