1) the files that you receive by bluetooth or from the SD card ?

I am working on increasing the sampling rate of the board as well as writing the data to the SD card only to speed up its current writing speed. So that I am interested in your work in this discussion

When I tested the function of writing OpenBCI data to the SD card, I met some following issues

collect the data and stored in the card without a need of USB dongle? I tried to run the Android app supported in Github but the board cannot be detected even though I switched it to BLE.

To do what I want this code works but since it depends on the context and the type of SD Card, it should be tested carefully...

//  In File     SD_Card_Stuff.ino  ***** Call to overloaded writedata function in order to call OBCI.push() during SD busy state *******************

To only write on the SD Card, not using the RfArduino, suppressed the freezing problem...

The aim of the second link is not related to the problem raised by the very long "busy state" of the SD interface...

There are some comments on the thread below, mentioning the possibility of using "double buffering" to achieve maximum SD card writing speed with no lost data.  If you post your question on

There is a certain regularity of the overruns occurences which depend on the quantity of data written on the SD card...

Yes in this card it's the war for the "SPI".

the two ADS1299, the accelerometer and the SD card, when the PIC has two SPI ports and one should be reserved for the SD card to avoid overruns and such. Maybe DMA should be used too for this applica

The way SD card, AD, RFmodule are interconnected ?

Compared to the 30MBytes/S of a "slow" card the 20/8 MBytes/S of the bus is very slow .

This is a good question. I don't know why the writing slows down so much. I think it is important to get the highest quality card that you can in order for it to work well. The Arduino SD card library

I bought a 16Gb card from Transcend ( TS16GUSDHC10 ) Class 10 , 30MB/s, 200x.

the Dongle radio. Also, you can start the writeToSDonly functionality by sending an 'N', and stop the writing by sending a 's', if you like. That will add a note in the SD file to mark the stop time,

@biomurph, thank you for the "write to SD only" code.

Oh, and by the way, while it is writing to the SD card, it has some serial verbosity every 256th block.  Here's an example of the serial output on the arduino IDE terminal windodw

I am a little bit shy as regards the uplaod on the card(map), there is so much problem brought back(reported) on the forum.