Disconnect button doesn't work on Windows 11

[Dbarve]

When I click disconnect after connecting my Arduino the monitor continues to plot. The Arduino code here is just a simple sin wave generator and I am not sure if this is a bug or if I need to have a Serial.read() on the Arduino to indicate that it needs to disconnect.
Thanks.

Windows OS 11 Build 22631
Serial Monitor Rust version 0.3.3

[hacknus]

Hello @Dbarve, thanks a lot for the report!
What is the rate at which the Arduino puts out data?
Can you tell me what happens if you unplug the Arduino while it is connected?

You should not require a Serial.read() on the Arduino/client side.

[Dbarve]

The Arduino is sending out data at a baud rate 115200. If I unplug the Arduino while the Serial Monitor says connected, it keeps plotting data.

in the above image, I unplugged the Arduino near where my cursor was (where the coordinates show).

[hacknus]

Thanks for the info. Does the Arduino continuously send data or is there a delay between each Serial.write()?

Will it eventually stop when you wait long enough or does it never disconnect?

I'm thinking that the serial buffer is filled faster than the Serial Monitor reads it. In that case you would need to decrease the rate at which the arduino is printing data - e.g. adding delays between the write-calls. Baud Rate is okay.

[Dbarve]

The Arduino continuously sends data, there are no delays. In the image below I unplugged the Arduino at ~2 seconds and this was the result. The serial monitor stopped plotting at the end.

Also I have noticed that whenever I try to send a command through the command line it does not seem to be doing anything. I tested sending the command through the Arduino serial port and the values were affected properly.
This is the code I was using to test the serial communication.

  if (Serial.available() > 0) {
    // change to function inseat of having everything here
    String input = Serial.readStringUntil('\n');
    input.trim();

    if (input.length() > 0) {
      char command = input[0];
      char filterType = input[1];

      switch (command) {
        case 'c': // Change cutoff frequency
          if (filterType == 'h') { // High-pass filter
            float newCutoff = input.substring(2).toFloat();
            high_pass_filter.updateCutoffFrequency(newCutoff, kSamplingFrequency);
            Serial.print("High-pass cutoff frequency changed to: ");
            Serial.println(newCutoff);
          } else if (filterType == 'l') { // Low-pass filter
            float newCutoff = input.substring(2).toFloat();
            low_pass_filter.updateCutoffFrequency(newCutoff, kSamplingFrequency);
            Serial.print("Low-pass cutoff frequency changed to: ");
            Serial.println(newCutoff);
          } else {
            Serial.println("Invalid filter type");
          }
          break;
        case 'r': // Reset filter
          high_pass_filter.reset();
          low_pass_filter.reset();
          Serial.println("Filter reset");
          break;
        default:
          Serial.println("Unknown command");
          break;
      }

[hacknus]

The Arduino continuously sends data, there are no delays. In the image below I unplugged the Arduino at ~2 seconds and this was the result. The serial monitor stopped plotting at the end.

Yes, you need to add delays. Serial Monitor is currently on windows not able to plot at a high frequency. I don't know why this is, on linux and macOS I don't have this issue.

Also I have noticed that whenever I try to send a command through the command line it does not seem to be doing anything. I tested sending the command through the Arduino serial port and the values were affected properly. This is the code I was using to test the serial communication.

Can you echo the command from the arduino before the switch?
The default delimiter of the Serial Monitor is '\r\n', so in case you haven't changed this, your Arduino code should be:

>     String input = Serial.readStringUntil('\r\n');

[hacknus]

I managed to remove a 1 ms timeout on the master branch. Can you pull and test if this improved the performance?
Thanks!

[hacknus]

@Dbarve were you able to check again?

[patzf]

I have a similar Problem. The tool does not disconnect on Win10/11 when reading serial data that is sent with a period of ~2ms. May I ask why the stream "rate"is related to the "disconnect" functionality? =)
Also, as I am not an Arduino guy: is there somewhere a minimalistic docu wich data format the "plotter" is expecting? Thanks a lot!

[hacknus]

Thank you for the input @patzf!
If the stream-rate is too high for the serial backend (apparently this is platform specific and maybe even built into the OS) it will fill up the buffer faster than serial-monitor can read it out. If you then disconnect, there is still data in the buffer and it will still be displayed in the serial monitor. With 2ms this should however not be the case.

Can you tell me which version of the serial monitor you use and if it is a pre-built release or if you compiled it yourself?

The serial monitor just takes a string and splits it at ","
If the pattern (number of values between commas) is the same for about 10 lines it will start a plot-line for each value.
Minimal working example would be to just print one variable without commas, this should result in one plot line.

[patzf]

I use the latest prebuilt Windows Binary. The interesting thing is that other serial monitors all disconnect perfectly fine, no mattern whether the good old HTerm or the plotter from https://github.com/hyOzd/serialplot/releases/tag/v0.13.0 , to just name two.

Also no line is drawn when i simply send comma separated 8 bit numbers and i also tried to just separate the values without coma but /n/r instead. Guess I understood it wrong =)

[hacknus]

which version of the pre-built releases?

hmm okay, I definitely have to look into this.. I only tested previous versions on windows and they seemed to work fine.

yes, currently it splits the received message buffer at \r\n to extract separate lines, so this is required, otherwise there is no way to tell if the message belongs to the previous timestamp or a new one.

can you send me an example of what you are sending? the 8-bit values?

[patzf]

Will do so soon!