Creating log file on Thingy:91

[Gmaciek]

Hi,

I might have missed the answer to this question in other threads, but: what is the best way to store/get log data from the device that is not connected directly to the computer?

I am testing the MQTT & GPS functionalities and for that I need to see the behaviour of the device "in the field", especially what is happening when there is no coverage or GPS signal and so on. So for that I would appreciate a way that does not require having the device connected with a wire to the computer. I am aware of NRF_LOG existence, but it seems that it uses either UART or RTT and both require connection with COM port.

Can I create a log text file, and if yes, where would it be stored and how to access it? And if I can't - is there any other way?

[Øyvind]

Hello, 

We do have a solution to use BLE to transfer data. There is an application, the Connectivity Bridge, that you can program to your nRF52840 (nrf on the Thingy:91. Once programmed and enabled, you should be able to log via NUS to your preferred BLE terminal e.g. this terminal for Android devices.

Let me know how that works for you!

Kind regards,
Øyvind

[Gmaciek]

Hmm, that still requires relatively close distance to the computer/terminal, right? Isn't there any way to store the log data on the device and access it afterwards?

[Øyvind]

My apologies for the late reply. 

Gmaciek said:

Hmm, that still requires relatively close distance to the computer/terminal, right?

 Yes, that is true! 

Gmaciek said:

Isn't there any way to store the log data on the device and access it afterwards?

 There aren't any samples at the moment, however, there are some samples/documentation in Zephyr you could look at.

Zephyr - File Systems

Zephyr - File System samples

Kind regards,
Øyvind

[Gmaciek]

Thank you for suggestions, the file system looks like something worth looking at.

Recently I also came into the NVS - it seems also like an easy way to store data, however I am quite hesitant about using flash memory for such purpose. My biggest concern would be the lifetime of flash memory, I couldn't get into Thingy's specification, except that the maximum number of erase cycles is supposed to be 10 000.  I lack sufficient knowledge in this topic - so could you share your opinion on using the nvs for logging? Considering that I might need to log the information quite often, let's say - few times a minute.

What is actually the difference between File Systems and NVS?

[Øyvind]

You should note that Zephyr also supports SDHC, which could be an alternative to storing directly to flash on the unit. 

Gmaciek said:

What is actually the difference between File Systems and NVS?

 Non-Volatile Storage is the storage space itself, while the file system is how information is stored i.e. FAT which is readable in Windows, Linux, and Mac. The Zephyr documentation has a good explanation of NVS and the file systems that are supported by Zephyr.