Wireless sensor networks are today more and more widespread. Along with the installation of more and more networks, a number of new standard documents has also been produced to update the regulation concerning data communication between sensors and data collectors. Differently, less attention has been paid to the different modes of powering the local sensors. At present, the energy required for local sensors functioning is essentially battery provided, despite the battery supply is often recognized as a critical aspect of remote sensing. In fact, the periodical battery replacement is sometimes non-strategic and troublesome, especially for those sensors which have to be installed in difficult to reach sites, or are integrated into medical implantable devices. In the abovementioned circumstances, battery-less sensors appear to be attractive, both from a pragmatic point of view, because of the strategic role they can play in critical scenarios, and from an innovation-oriented point of view, because of the novelty that wireless power transmission can add to a new groundbreaking remote sensors technology. Wireless power transmission technologies are capable of supporting battery-less sensor functioning. In this paper, first the main issues related to alternative remote devices powering solutions are plainly discussed, then, a resonant-based induction power transmission system for supplying a sensor network is also presented.