One of the limitations of the new device I've been using is that it constrains its output to a range ~25-95 Agtron gourmet scale, but one of the first significant events in coffee roasting involves that measurement going off the scale (my benchtop analyzer would put it around 130). Decaf coffees, however, often start out brown so they reach their brightest at a reading that's still in range. That inflection from coffee getting brighter to coffee getting darker is where tasteable chemistry starts
It always feels a little strange fixing a bug in a program written in a language where I rate my proficiency as "I know of this language", but having a REPL helps. Anyway, this is how my current graphs looked today. Much better. I'm still not doing anything on the receiving end to clean up that signal.
With default data acquisition hardware settings, no calibration (just going from the specs), and no attempt at doing anything to smooth things out, this is my first attempt at capturing degree of roast data in Typica. Apparently when the measured values are out of range on the high end the signal drops out on the bottom (I need to verify that and make sure it's not a bug in my software). It's a noisier signal than I'd like, but I've got some tricks that might help with that. Still promising tech
Author of Typica software for coffee roasters.