does anyone know if it is possible to buy or build a really small tracker that uses wifi only.
I'm hoping to begin a masters studying bats, possibly in China, I expect in China the areas that the bats fly around will be at least partly covered by the wifi network. GPS is still mostly too large for 50g bats, radio tracking would work but then I need to chase them and find out where they are and would have a lot less data points. It would be nice to just be able to recatch them and download approximate data of where they went from a microSD. I expect someone might sell this type of thing somewhere (probably in China :) ) but if not I have built things before so I would be interested in basic suggestions for how to go about that too, just not sure if I could make it small enough if I was doing it myself.