/*
   BH1750FVI_angle_measurement.ino

   Experimental application

   first take a reference measurement for 5 seconds
   holding the sensor flat under a light source.

   Then take a second reference for 5 seconds 
   holding the sensor at 90 degrees.

   Thereafter hold the sensor at any angle and the
   Arduino will estimate the angle based upon the
   Lux level compared to the references.

   First trials are not not too bad, roughly within 15° accuracy
   
*/