Energy harvesting - power supplies without batteries or cables

Energy Harvesting makes use of minimum amounts of ambient energy like thermal gradients, vibrations or light. Collecting these amounts of energy a long time to power short actions like sensor measurements or wireless data transmissions is the key of energy harvesting. A lot of research and development activities are on-going world-wide, addressing materials, devices, systems and applications. Promising field trials are carried out in various application areas, most of them in wireless sensor networks. First products are available, mainly in the industrial and automation area whereas consumer products are predicted for the next ten years. The characterization of potential ambient energy sources shows a broad range of the typical parameters and thus big challenges for the system design. Different development approaches are possible to arrive at a cost-optimized power supply solution. Generic energy harvesting systems are composed of an energy transducer, a power management, some kind of energy storage and the final application. Matching of the different functional blocks will result in maximum energy output, minimum device cost and board space.