Is there a tool that automatically checks the light conditions of a room via a notebook camera and writes the values into an .csv file?
If not, does anybody know somebody they can talk into creating such a tool? 
I don’t know of a tool like that for a notebook, but it’s pretty easy to make for an iPhone. Would that help?
If you take the iPhone approach, here’s some info to help get it built: http://stackoverflow.com/questions/10025764/iphone-light-sensor-vs-camera-to-measure-the-light-intensity
There are a number of light-meter apps for the iPhone designed for photographers, although I cannot comment on wether they provide continuous logging though: http://photography.tutsplus.com/articles/quick-tip-a-look-at-5-iphone-lightmeter-apps--photo-7192