  For a transparent well with a known volume capacity, changes in fluid level
result in predictable changes in magnification of an overhead light source. For
a given well size and fluid, the relationship between volume and magnification
can be calculated if the fluid's index of refraction is known or in a naive
fashion with a calibration procedure. Light source magnification can be
measured through a camera and processed using computer vision contour analysis
with OpenCV. This principle was applied in the design of a 3D printable sensing
device using a raspberry pi zero and a camera
