Privilege separation best practices

I have a light meter which has Python3 libraries which seem to require root access. I don't want the whole script to run as root, just the part which reads the light intensity. I wonder what are the established best practices for dealing with that.

Running a script on-demand just to read the meter is very sluggish and introduces a variable but massive amount of lantency into the workflow. So I am guessing something needs to be left running. How should other scripts and progrmas then poll the script which monitors the meter? Sockets? FIFO pipe? Others?