un,
The small-size vibration-driven generator using magnetostriction effect
A magnet is attached for bias magnetization.
http://www.geeky-gadgets.com/tiny-vibration-generator-may-replace-button-batteries-01-12-2010/
J'avoue bien humblement que je n'ai pas tout compris, ni si il faut vibrer pour recharger ou si le magnétisme ambiant suffit, ni ...
Mais bon, l'idée de me passer des piles boutons me plait ! ;)
Je cite Ubergizmo :
A Japanese university researcher has come up with a small vibration-powered generator that measures in at 2 x 3 x 12mm only and is capable of churning out 1.56mW of power with a vibration of 357Hz. According to him, the energy density is high enough to replace a button battery. The energy density of this generator is about 22mW/cm3, which is roughly 20 times higher than the energy density of a normal small vibration-driven generator. If this means that we won't have to fuss about replacing the batteries in certain devices in the future, we're certainly looking forward to this.
Le site du chercheur Japonais : http://techon.nikkeibp.co.jp/english/NEWS_EN/20101201/187802/