Extreme Lag on Serial Line

macman20

in Integration and Hardware • 1 year ago

Hello, I've noticed that there have been multiple other posts about this problem but I haven't found that many of them have solutions and of the ones that do, none of them seemed to help with my lag. I'm working on a processing front panel to run a quadrotor I've built. When I use the Arduino serial terminal I get lightning fast serial connection and response, so i've been typing out all the feedback to the Arduino by hand. Obviously that's not practical, but a test to show wiring/OS is not the problem here, it has to be something in Processing.

The problem is right now I have feedback being sent to the dashboard about ten times per second and right now just the first bit of information is being parsed and displayed for simplicity purpose. This was extremely laggy so I decided to print to the terminal in processing. It appears that whenever the arduino sends "/t" or "/n" it will pause for 100 ms or so, just an estemate. Otherwise the chunks of text appear just as they should rapidly as they would in the Arduino term.

Another weird thing, just for thought is that the transmit is running lightning fast from the computer, I know this for sure because whenever I move the slider on the dashboard to change the throttle it will make the rx light on the quad pulse.

This is what I've got for the main code running the program:

void setup() {
size(360, 400);
font = loadFont("BankGothicBT-Light-24.vlw");
textFont(font);
println(Serial.list());
throttleBar = new VScrollbar(80, 20, 40, height - 95, 1);
arduino = new Serial(this, Serial.list()[1], 57600);
}
void draw() {
background(40);
fill(255);
lastThrottle = throttle;
throttle = int(throttleBar.getPos());
text("Throttle: \n" + throttle, 20, height - 50);
text("xAng: " + xAng, 180, 45);
throttleBar.update();
throttleBar.display();
sendData();
//parseDashboardData();
print(char(arduino.read()));
}
void sendData()
{
if (lastThrottle != throttle) {
arduino.write("DAT:" + ((9 * throttle) + 1000) + ",");
}
//print(char(arduino.read()));
}

I don't believe the parsing is causing the lag because when I comment out the parse method it will still lag just as much.

Any help would be greatly appreciated.

Thanks!!

Replies(4)

benja

Re: Extreme Lag on Serial Line

1 year ago

Hard to tell where your problem lies without seeing the whole code.
Could you reproduce the behaviour in some simple test-code?
Or post the whole arduino- and processing-code?

When i send a message to arduino from processing, the time until i recieve a response is between 4 and 6 ms, if i use a high baud-rate.

macman20

Re: Re: Extreme Lag on Serial Line

11 months ago

Oh, sorry I took a bit of a break from my quadrotor project when school started again and missed this post. Thank you very much for responding. Resuming some work again now that I'm back into the swing of things.

For now I can send the whole programs, if that doesn't help I can try and make smaller scale reproductions of the problem. The Quadrotor code is rather massive right now, but will only get bigger. Sorry for the information overflow.

Arduino code: http://pastebin.com/9M6NbT3Z

Processing code: http://pastebin.com/usYtiBTW

Sorry for taking so long to respond, I spent time working on a test mount for the quadrotor in the meantime. Thanks for the help!

benja

Re: Extreme Lag on Serial Line

11 months ago

Hey,

i can't test the code without the hardware, but after having a quick look into the processing-code, it seems that your problem is that you call parseDashboardData () once on everey frame. With the default framerate, this is 60 times per second. In this function you read one byte, so there are 60 bytes read every second. I think you send more than 60 bytes per second (in your updateDashboard()-function).
So you send the data faster than you read it, which results in a pretty big delay after a short time.
I would recommend to use serialEvent() in processing. The advantage is, that it works asynchronus and you don't have to care about the amount of data wich is send.

macman20

Re: Re: Extreme Lag on Serial Line

11 months ago

Thanks a lot, I would have never come to that conclusion, it's working much faster now.

Hopefully now I don't hit too many more bumps with the dashboard.

Thanks for all the help!

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