Set your python environment up first. Assuming you have python installed, and a healthy copy of pip, then these days it's best to setup a python virtual environment for each project, so search learn.adafruit.com for a guide how.

Get the converter here: https://github.com/tyeth/Adafruit-Wippersnapper-offline-mode-JSONL-data-converter

Once setup with a python virtual environment and inside the extracted zip (or cloned repository) install requirements:

pip install -r requirements.txt

Then before running the converter, turn off + unplug the Wippersnapper Offline device. Remove it's SD card and insert into the computer, copy the logs off of the SD and into the converter folder. Finally insert the SD back into the offline logger and plug into the computer, then copy the config.json and wipper_boot_out.txt to the converter folder too.

Finally run the converter:

python jsonl_to_xlsx.py -r ./

All .log files will be converted into excel files. If the data is more than 1million rows then it will be output as CSV instead. If you prefer CSV then add --csv, and for a single merged output file then add the --merged argument.

You can run the converter without options for interactive mode, or --help argument to show help: