Large data transfer over ble.

[Thomas]

Hi,

I would like to have a system such as follows:

• Taking sensor data storing it locally till around 100 samples (Once per second)
• Log this data to the SD with a time stamp
• Then storing this data to an external SD card. (Utilising the fatfs example code in the SDK) Around  2 Mbytes
• I then want a mobile device to request this data.

What therefore, is the best way of transferring the data from the SD card to BLE to be picked up by the mobile application.

Do I need to set up a GATT connection and wait on a notification change that I set in the Nordic board?

If so is there an example of this or a good starting point.

Would this post be a good starting point? : https://devzone.nordicsemi.com/f/nordic-q-a/553/dealing-large-data-packet-s-through-ble

If so what example is good to work from. Thanks

[Simonr]

Hi Thomas

The error codes can be looked up using ble_err.h and nrf_error.h. Error 0x3002 is BLE_ERROR_INVALID_CONN_HANDLE and defined as being an invalid connect handle. NRF_ERROR_STK_BASE_NUM is defined as 0x3000 in nrf_error.h.

Have you edited the ble_app_pwr_profiling example to be connectable or is it just advertising and not connecting to a central? I think it would be easier to avoid these connection errors if you based your project in an example that is already using connectable advertising by default.

Best regards,

Simon