SparkFun Forums

[JustPlaneD]

Does the OLA come 'out of the box' with the capability of exporting (serial data) files saved on the SD card via the onboard Bluetooth radio?

Regards,
JustPlaneD

[PaulZC]

Hi @JustPlaneD,

Unfortunately, no, it cannot.

Adding BLE connectivity to OLA was always on our roadmap, but we just haven't had the time or resources to be able to do that. You can find some discussion about possible alternatives here:

viewtopic.php?p=222127#p222127

Best wishes,
Paul

[JustPlaneD]

What is the onboard BLE radio capable of? Specifically regarding logging functions?

[PaulZC]

Nothing. Sorry!

The hardware and Mbed OS both support BLE, but we just haven't had the time or resources to be able to add support in the OLA firmware. It's a big project and we have new hardware coming where it will be _much_ easier to support Bluetooth and WiFi connectivity.

[JustPlaneD]

Paul - It's been about a year since the above post. Any progress getting BLE connectivity to the logger?
You mentioned new hardware coming - please point me to any new SF products that can log serial data - then - transfer via simple BLE interface.

[PaulZC]

Hi,

Sorry, no progress on adding BT connectivity to the OLA.

The new hardware is the DataLogger IoT 9-DOF but unfortunately the firmware does not (currently) support serial logging and is currently focussed on WiFi connectivity not BT.

Do you really need BT / BLE connectivity? Or would WiFi do? I don't have a stand-alone example to share with you, but it is certainly possible to: have ESP32 log serial data to microSD card; have the ESP32 connect to your WiFi network - or act as a WiFi hotspot; list the files on the microSD card and allow you to transfer them via a web page. Our RTK products offer the microSD file transfer functionality - but don't do serial logging. I think what you need is a hybrid of some serial logging code and the WiFi web page Javascript file transfer code from the RTK firmware.

Can you let me know a bit more about what you're trying to achieve? Will you have physical access to the hardware? Could it have two separate modes: logging and file transfer. Would it be OK if you need to hold a pushbutton at reset / power-on to put it into the file transfer mode? Or does file transfer need to be "always on"? Do your log files need accurate date and time stamps - does the logging hardware need to know the time? Could it get the time via WiFi (NTP) - or are you able to set the time manually like the OLA?

Best,
Paul

[JustPlaneD]

Paul,
Thanks for the timely and detailed response.
BLE is a requirement on our end due primarily to power restrictions. WiFi isn't a possibility as the receiver of the stored data is tied up on a WiFi connection doing other tasks and can't be disconnected-connected-disconnected-reconnected. Additionally, once installed the device is expected to be inaccessible. (sorry, no buttons). Time stamps are not required - however, thanks for mentioning it as it could be advantageous and deserves consideration.

I'm in a quandary. It seems like the functionality of -- log from serial and dump to BLE -- would be a natural. Am I the only one to see (need) this functionality?

Regards and Thanks for your time,
JustPlaneD

[PaulZC]

Hi JustPlaneD,

What you are asking for is really quite unique. I personally don't know of any products / software that would let you:

Log serial data to microSD file
Periodically close the file and open a new one
At random points in time, allow a BLE connection from an App / application
List (provide a directory of) the microSD files
Allow selection of a single file
Echo its contents to the application over BLE
Have the application save the data to file

The "OLA" code and application need to be able to work together to list the files and transfer a single file. You'd need to put development work into the application too, not just the OLA BLE functionality.

It would be more straightforward to echo (broadcast) the serial data to BLE, like a Serial terminal / monitor, and have an Android App like "Serial Bluetooth Terminal" save the data. If you can avoid the list-and-select-file features described above, and limit yourself to a single file, it becomes much more achievable:

Log serial data to a single microSD file
At random points in time, allow a BLE connection from an App / application
Echo the entire file contents to the application over BLE
Have the application save the data to file

I'm pretty sure you could get something working there, using Android Serial Bluetooth Terminal as the App. Not with OLA, but ESP32 could certainly do it.

How much data do you need to log? I wonder if you could also do this using a Dynamic RFID tag? This one - https://www.sparkfun.com/products/21274 - can store up to 8kBytes of data which can be read using a mobile phone App. You write data to the tag over I2C in a format which the App can read and save. The App can delete the data too once read.

I hope this helps,
Paul