'numPacketsDropped' errors every ~ 15 to 30 seconds, when streaming via WifiShield and TCP

joe_westrajoe_westra CA
edited February 2019 in OpenBCI_GUI
I'm using a Cyton (firmware V 3.1.1) , Daisy and Wifishield (V 2.0.5) and when streaming data via TCP the output from the terminal of the compiled version of the OpenBCI GUI (V 4.0.4, HUB V 2.0.5) reports that groups of ~20-30 packets are being dropped every 15-30 seconds.  I am using Wifi-direct.  When searching the codebase for a string in the error message ("numPacketsDropped") it points to the InterfaceHub.pde file.  The description at the top of that file speaks about the Ganglion explicitly (is this just an artefact from the code being re-used and the comments not being changed?)

Furthermore, when I use the UDP protocol instead, only one instance of packet dropping is relayed: immediately on starting the stream.  My goal is to minimize the latency and drop-rate of packets, do you have any advice?  Am I wrong in assuming that this 'packet drop' error is network specific, and not related to gui rendering of the packets data?

Any feedback would be appreciated!

Thanks!

Comments

  • wjcroftwjcroft Mount Shasta, CA
    Joe, hi.

    What sample rate are you using? Does the lossage happen at some rates and not others? I assume you have no dropped packets using the Cyton without the Shield.

    You are correct the Hub is used for both Ganglion and Cyton. Originally it was created for Ganglion, then Cyton was added. 

    Regards,

    William

  • produceconsumerobotproduceconsumerobot New York
    edited February 2019
    Hi Joe,
    Sorry to hear you've had some dropped packets.
    Check out this issue on github and see if the options listed there help!
    Cheers,
    Sean
  • joe_westrajoe_westra CA
    edited March 2019
    Thanks for the help William and Sean, I really appreciate it!

    William:

    -I was initially using 1000hz and 16 channels with 10ms latency over both
    TCP and UDP.  As per your suggestion, changing to 5000hz  while using
    TCP reduced the packet drop issue to an occurrence ~once every 5
    minutes.  Using the UDP protocol at 10,000hz seems to be even more
    reliable, however my sample size is small at this moment.  What
    is the threshold for packet drop reporting?  The smallest amount of
    packet drops that I have seen reported is 8, would the OpenBCI_GUI
    software report 1 packet dropped?

    -After 10 minutes, there were no packet drop issues when using Bluetooth.

    -When attempting to use the WifiShield and UDPX3 I receive an error message
    stating that the WifiShield firmware is out of date, which prohibits UI
    initialization and data streaming.  WifiShield firmware is V 2.0.5 which
    is the most current version on


    What firmware version is required for the WifiShield to use UDP x 3?  FTR
    I have tried downloading the pre-compiled version of the OpenBCI GUI (v
    4.0.3) and Hub (V 2.0.4) but I receive the same error message when
    attempting to use UDPx3.

    Sean:
    That information was highly valuable, especially the background on UDPx3.  Thank you.  Using the UDPx3 protocol would be highly ideal.


    Once again, thank you for the guidance!
    -Joe
  • wjcroftwjcroft Mount Shasta, CA
    Joe, would you mind placing your recent post on the same issue page. That should be the primary place for tracking the issue and updates.


    You can also post here on this thread, but consider it secondary.

  • wjcroftwjcroft Mount Shasta, CA
    re: packet drop reporting threshold. There should not be any lower limit. '1' is possible.

    Not sure why your latest shield firmware cannot work. You might need 3.1.2 on the Cyton mainboard. Perhaps Sean has a suggestion.

  • joe_westrajoe_westra CA
    Thanks William, I have done as requested.  That info on packet drop reporting is great to know, thanks!

    If Sean doesn't have any other suggestions right now I'll try updating the Cyton firmware and see if I have any more luck.\

    Thanks again!
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