I need to send logged sensor data in external flash to a phone via BLE. What is the best way to accomplish this?
How should the GATT be designed for transferring large chunks of data stored in external memory over BLE to an app?
What is the size of the data that you're going to send? You might need to partition the data into chunks. I would recommend using the Nordic Uart Service, more specifically the ble_nus_data_send(). This thread might be of interest for you.
The size of data to be sent depends on when the phone was last connected to. It can be anywhere between 100 bytes(hourly data) to 500k Bytes(months worth of data). Is there a scheme to make this feasible? Thanks
We don't have an example that partition a large set of data and then transmits it, so this is something you would have to make yourself. We do however have examples that shows how to use the necessary functions for sending data such as the ble_app_uart example or our unsupported Image transfer demo on Github.
while I review the image transfer demo, Any hints/suggestions about how to go about it?