Basic plant sensor kit which currently outputs; - soil humidity - light levels - human presence Hardware interface based loosly on recollection of Martin Howse's experiements with the Wheatstone Bridge[1] and incorporates parts of a design published by Rob Faludi[2] which was in turn based on a design by Forrest Mims, with nods to L. George Lawrence, Botanicalls and the long and tangled path from Jagdish Chandra Bose. [1] during piskel08 [2] http://www.faludi.com/2006/11/02/moisture-sensor-circuit/