DIY inline refractometer project from Anfractuosity:
The idea of this project is to image the refractometer output, then convert the position of the blue line, to a digital reading, using image processing. The idea is to measure the brix of wort during mash and sparging, so that sparging can be stopped around 1.010 SG, to avoid tannins.
More details on Anfractuosity blog.
Check out the video after the break.