An electronic device, for example an irrigation controller, accumulates energy from a source of energy, for example from incident light, in order to progress, over time, from an inoperative un-powered to an operative powered condition in a positively controlled, graceful and orderly manner. The device...http://www.google.com.au/patents/US5661349?utm_source=gb-gplus-sharePatent US5661349 - Graceful energization and degradation of an electronic device micropowered by a source of energy in its environment, particularly an irrigation controller powered by light energy
