Downloads and convert data from a Light Log <http://lightlogproject.org>

Raw data bytes are downloaded from a Light Log device through a serial
port and saved as a CSV file for easy processing with external tools.
Time stamps use calculations based on the local systems time, so be
aware your local clock should be reasonable accurate when downloading.
Comment correction
Spend less time allowing MCU program downloads.
Tidy up LED pulsing and MCU speed