https://devzone.nordicsemi.com/f/nordic-q-a/16654/nrf51822-to-microsd---high-levelHi there, I&#39;m definitely a newb when it comes to wireless communication and communication protocols so I&#39;d like this question to be answered at a higher level than what I&#39;ve read on a prior &quot;Mass storage with NRF51&quot; post. My question is what hoopsen-USTelligent Community 13Tue, 27 Sep 2016 12:42:35 GMThttps://devzone.nordicsemi.com/thread/63715?ContentTypeID=1Tue, 27 Sep 2016 12:42:35 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f074ef2d-b359-46ea-83c0-0ac09cd01bf8Ole Bauck<p>Hi,</p> <p>As long as the file is not too big you should have no problem in sending the file. You will have to make your own service that take care of the transfer. For example DFU OTA (Over The Air) sends a firmware image (.hex file) over bluetooth to update the application. It might be difficult to look at this as an example though as it is quite complex (we get a lot of questions about DFU every day).</p> <p>For storing the data to the SD card you can use <a href="https://github.com/katphlab/nrf_fatfs">this implementation</a> of a file system. It is based on <a href="http://elm-chan.org/fsw/ff/00index_e.html">FatFs</a>.</p> <p>There is no way to tell the iphone natively that the bluetooth connection is for mass storage (at least that I know of). You will have to make your own app for transferring files.</p> <p>You should also be careful when you connect to USB so that not both devices try to write/read to the SD card at the same time as this may corrupt the data.</p> <p>Ole</p><div style="clear:both;"></div>