I enjoyed reading Ian Verhappen's article on pervasive sensors (February 2014). Our vision of pervasive sensors encouraged us to find innovative ways to not just power sensors, but also communicate their data. FYI, we at OptiXtal have created a prototype of a battery-free, ambient-light-harvested device that detects temperature and presence and sends it wirelessly to a manager for action.

See http://optixtal.com/optixtalwp.htm.