This article explores nanotech machines and says they need a better power source than batteries. The creation of nanogenerators makes power on a tiny scale that may permit the use of waste energy in the form of vibration or the human pulse to power devices. Piezoelectric nanowires could capture the energy to run nanodevices. The authors believe the major application of this technology will be in medical devices such as pacemakers and for implantable blood sugar monitoring devices for diabetics. INSET: Ambient-Energy Harvesters.