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.