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Ultra-Compact Electromagnetic Generator

Harvests Rotational Kinetic Energies at a Range of Vibrational Frequencies to Power Portable Electronics Platforms

This compact, ultra-light device efficiently harvests energy from motional sources. Although methods for harvesting kinetic energy exist, conventional devices used are large and generate limited quantities of energy. For instance, some designs involve a weight attached to a vibrating spring, where the frequency and amplitude of its oscillations generate approximately 100 microWatts of energy. However, researchers at the University of Florida have developed a solution by creating a device the size of a AA battery that passively harvests significantly larger quantities of energy under normal human activities. By utilizing the rotational motion of internal cylindrical magnets, this device can potentially provide efficient energy to various electronics.



Ultra-compact device that harvests kinetic energy for portable electronics, soldier subsystems, robotic platforms and sensor networks



  • Incorporates a rolling magnet design, increasing energy harvesting capabilities
  • Offers avenues for miniaturization with significantly higher power density, allowing manufacturers to implement generator in small-sized electronics
  • Useful in a variety of governmental and private sector applications, providing multiple market applications
  • Enables energy harvesting over a range of vibrational frequencies and amplitudes, reducing the need for a specific vibrational signature


The ultra-compact electromagnetic generator provides high-energy-density motional power sources for portable electronics, soldier subsystems, robotic platforms and sensor networks. The heart of the power source is a free-rolling cylindrical or spherical magnet that generates power in surrounding coils via magnetic induction. When external motion is present, these magnetic coils begin to roll freely, generating electrical power. Converse to consumer shake-light emergency flashlights, this device offers avenues for miniaturization and significantly higher power density via rotational motion rather than translational. By including a wide range of vibrational frequencies and amplitudes, this system offers significant advantages over previously explored resonant mass-spring-damper energy harvesting systems, which require periodic vibrations at a single specific frequency and exhibit unfavorable scaling for miniaturization.

Patent Information: