Higher sample rates / sample at 2000hz to SDcard?

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  • @gvzb19 no trouble at all! I just don't want you to use broken code haha

    We're not doing preorders, make sure to join the newsletter.

    The current GUI will work with the v3.0 firmware, if you find it does not, that's a problem! Open an issue on the GitHub of the OpenBCI_32bit_Library. Thank you so much for you continued patients!

    Thanks

    AJ
  • Is it possible now to collect data from two channels at 8000 Hz sample rate?
  • @abojensen

    As long as you have a good wifi network, you should be able to do 8 channels at 8,000Hz!
  • Yes I should, but have anybody out there done this?
    How much coding and configuration in miscellaneous languages do I need?
  • The shield just came out yesterday, but i have done this and made it pretty easy to do!

    What programming language do you like? I can write an example and show you how easy it is!
  • @pushtheworld - Excellent - just ordered one!

    Getting past the bandwidth limitation of the bluetooth downlink and with the new functionality to integrate experiment presentation software and markers, OpenBCI is moving in the realm of a proper research tool.  Thanks for all the hard work.
  • @pushtheworld

    Hello again, i'm sorry about the long delay, i did testing with 2 different sd cards on both 2.0.1 and 3.0.0, and none of them seemed to work.
    i think it may be the boards sd-hardware thats faulty, or at least that seems like the only feasible explanation to me. 

    I've now gotten one of the WiFi shields though, and if i can take you up on the offer you gave abojesen i'd like to give python a go!

  • @tskips ;

    Re: SD Card - did you test with a different card? I verified SD works for at least the 14second write.

    Re: WiFi Shield I have built a simple Python native driver 

    The code still needs the sample rate setting (if you want to contribute highly encouraged) but this code will find your wifi shield, connect to it, sync with it, and start streaming from it, all with zero dependencies. 

       
  • edited September 2017
    abojesen @tskips and all

    The highest level way to get data from the WiFi Shield is the OpenBCI GUI. The GUI uses the OpenBCIHub for all data acquisition.

    The OpenBCIHub is a cross platform desktop application that runs a server locally on your computer. Using TCP, any application can search for, connect to, set channels, set impedances, start streaming, stop streaming, and you get data as it's parsed and such by the Hub. The Hub uses a bunch of different NodeJS drivers.

    There is a NodeJS driver for every board that supports every feature of every board. If we look at the WiFi shield, it can send data in two ways, raw or JSON. If you want sample rates such as 8000Hz, you will need to use "raw" mode. If you want say, below 500Hz, you can use the JSON mode. The JSON mode requires a lot more data then the raw mode! Get streaming in NodeJS example

    I just wrote a Python driver using the WiFi Shield API to open a TCP server that the WiFi shield can send data to. I know how to control the WiFi shield because I read the detailed HTTP server description here.

  • Hey @pushtheworld ;

    Here comes the message, that i meant to send prior to our meeting:

    "I've been playing around with it for a bit!
    So far i've been unable to get a stream going in the OpenBCI GUI, it seemingly drops the connection everytime i try.
    The following happens: 
    I select "Live(from Cyton)" -> "Wifi(from Wifi Shield)"
    I select my board, and verifies that an ip-adress is shown and a cyton board is connected, i then press "start system"
    This results in different error messages including: "Failed to connect to data source...", "init timeout. verify[...]"
    I am then returned to the board selection screen and can repeat the process. 
    (If i look at the connections to my access point, at the time i press start system, it seems that the wifi shield reconnects to the Wifi network.)

    The python driver though did allow me to retrieve a couple off succesful connections, and as such retrieve data. 
    Now this connection is still jumpy, especially if i dont manually type in the IP-connection:
    The last few times i've had it running, after a few seconds it returned this message:
    >>>
    failed to parse: 
    {"chunk":[{"timestamp":49956655... [a lot of samples data here] ... {"time
    Unterminated string starting at: line 1 column 252 (char 251)
    >>>"

    I am aware that most of what i describe above, can probably be attributed to the poor quality of my router and/or the latency settings.

    I have now acquired a SanDisk microSD card and will be testing this shortly.

    I thank you for the help so far!
  • tskipstskips Denmark
    edited November 2017
    I've now been able to acquire data on the SD-Card, and convert them using the OpenBCI GUI.
    I've started to do some prepatory data processing in python, but i still have only got data in 250 Hz, as i've been controlling the Cyton, from my bluetooth Dongle.
    Did you record the video while instructing me in the use of postman, or could you help me out, as i seeemingly don't remember as much as i would have liked to about setting this up.

  • I did not save that video recording :( 

    Can you list the requirements for your project?

    Sample rate, SD card? That was it right?

    You need to send a post request to /command docs here

    To send a command from postman, take a look at their docs here, specifically look at the "Raw" section under message body.
  • Hey @tskips checkout the new wifi shield firmware that will allow you to get high speed streaming for EEG!

    https://github.com/OpenBCI/OpenBCI_WIFI/releases/tag/v2.0.0-beta1
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