my tips for Cyton and Writing to SD Card

edited January 2018 in Cyton

I recently spent some
time working to get the Cyton to write to SD card - this captures the road I
took to get it to write.  Thought it may be helpful to someone. 
Still trying to read the data from the SD card (see post in Software regarding
array out of bounds exceptions) - but did get the data to the SD Card.  

Note - I followed the
steps in the tutorial and could not get output - again, here's how I resolved

  1. My problem ended up 
    being a formatting problem (I followed windows instructions in OpenBCI
    tutorial - NOTE these probably need to be updated given that the SD people
    have released a new formatter - see below??) - the only clue I finally got
    that I had a formatting problem was when I sent a text command via
    m,start,14sec,;\n.  The device responded with that it could not find
    a FAT16/FAT32 formatted SD card (very helpful error message - thank you
    who ever did that!).  SIDE NOTE on how to send commands to the cyton
    via electron hub using windows (1) download cygwin (make sure you get
    the 32 bit version, even if you have a 64 bit machine - else telnet will
    not be available) (2) select the inetutils package so that telnet will be
    loaded onto your machine.  After that, telnet localhost 10996
    from a Cygwin console window (if you have not used Cygwin, double click on
    the Cygwin window on your desktop after installing) - telnet will then
    allow you to send commands via electron hub running on localhost.
  2. I then reformatted the card
    using the suggested link in OpenBCI tutorial ( and focused a bit more
    this time)... The link will download version 5 of the software (different
    windows from the version in the OpenBCI tutorial).  This, for me,
    turned out to be the root of the problem - version 5 formats the
    SD to exFAT as opposed to FAT32 (with no options to change)...  So,
    then I turned to the MAC.  I tried to format using the MAC and FAT32
    (instructions in tutorial); however, the MAC forced me to make a decision
    between GUID and MBR for the SD card - I chose wrongly as things still
    would not work...  However this time - the cyton would not
    complain... it would act as if it was writing data during
    acquisition - but still no data on the SD Card.  Console window on
    the Processing IDE also offered no clues.
  3. Final solution for me: 
    Used the SD card program to repartition/reformat the drive to exFat (clean
    up after Mac).   Moved the card to a Linux machine, removed the
    partition using fdisk (wrote the new partition with w), and added a new
    partition of type FAT32 (W-95 LBA).  Formatted the card with
    mkfs.vfat -F32 -v /dev/sd??  where ?? = c1 in my case... For more
    information - the SD card is a 64 GB SanDisk Ultra.

A couple of other (clarifying) notes in terms of how
writing to SD card works with GUI...

  1. I ran the GUI from the
    Processing IDE.  Selected write the SD card in the drop down and the
    5 minute option - for testing.
  2. Then started taking data as
    normal (i.e. if I was not writing to SD card ... click on start
    streaming) - and the channels start reporting via the GUI
  3. Stopped after a couple of
    minutes, closed the GUI, turned off the Cyton, removed the card, put the
    SD card into my USB/SD card reader, loaded the reader into my windows
    machine, and located the test file.

Have not fully tested everything w.r.t speed, etc - but now I
have data.

 

 

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