7. Conclusions and outlook

Given the growing number of autonomous applications and the desire to reduce pollution by eliminating the need for batteries, generators that recover energy from mechanical vibrations are very promising candidates. At present, the three families of microgenerators recover low levels of energy (< 1 mW), sufficient for microsystems such as temperature sensors, but insufficient for everyday human needs such as recharging a cell phone. Thanks to the continuous improvement of materials and conversion structures, and to the reduced power consumption of many electrical appliances, it is highly likely that in a few years' time generators will be recharging our portable electronic devices. The general trend is no longer towards the excessive miniaturization of individual parts of a system, but towards the development of complete systems with increased autonomy. More and more broadband or multisource...