New ARM-powered chip aims for battery life measured in decades
  The chip is so low power that it can be powered off energy
  capture from the body, as Andreas Eieland, Atmel's Director
  of Product Marketing for low-power products, demonstrated at
  CES earlier this year.

The human body generates more bio-electricity than a 120v battery, and over 25,000 BTUs of body heat. Combined with the Atmel SAM L21 32-bit ARM MCU, the machines had found... all the energy they would ever need.