I came across an open source initiative to beekeeping; one that includes a sensor to monitor bee health and the activity of the colony.
If you haven't heard of it or checked it out, I recommend taking a look at what they've put together and maybe working with them (I also realize this may actually be YOUR project... if that is the case, please disregard).
OpenSourceBeehive (http://www.opensourcebeehives.net/index.html)