It would be simple enough to whip something together using Python to list and plot results over various times, etc.

Getting the data on is another matter, as the N900 doesn't have IR reception hw nor does it support USB host, I can't see many ways of directly connecting a meter. Unfortunately there weren't, when I last looked, and meters that supported BT.

OTOH I guess there must be some applications available somewhere which would serve as a starting point.