I like this. Appeals to my sense of tinkering. I have an RH Analyser, which is great, but I see exactly where you are coming from. Light sensor modules are available - this one I think is for arduino projects - I am out my depth here! http://www.elechouse.com/elechouse/i...cnafr3lt3i8ba6
It seems to me however that you have the ability to do this. The devil is going to be in the calibration, but I think you would learn a hell of a lot about printing by continuing to develop. Its a hobby after all, and we all get satisfaction out of it in our own way. I got the analyser when I started as soon as I realised that for me test strips were a time consuming PITA. With any "aid" you still have to learn how to use it - it doesn't do it all for you. I think now that I have printed for a year or so with the analyser, I have learned enough that I could quite quickly run test strips if I had to because you certainly learn the "feel" for time, contrast etc.
I am sure if you could rig up a light sensor straight in to the computer, if you took readings from a highlight and shadow you could use the information. It's how you interpret those readings into time/contrast for a particular paper. This could easily be done in a little program I'm sure. Fun project!