Abstract: A vibration-based power generator has a variable stiffness oscillator connected to a base. The oscillator comprises an inertial mass moving relative to the base in response to vibrations. The oscillator has a neutral position corresponding to a position of the oscillator when no vibrations are transmitted to the base. The oscillator has a first position where the mass is at a first distance and a second position where the inertial mass is at a second distance from a position of the mass when the oscillator is in neutral position. The second distance is greater than the first distance. A stiffness of the oscillator at the second position is greater than a stiffness of the oscillator at the first position. A transducer generating electric power in response to movement of the inertial mass is associated with the oscillator. A method of optimizing a vibration-based power generator is also presented.

Abstract: Methods, apparatus and systems are described as relating to electrostatic sensors for detection in micro or nano electromechanical systems. In exemplary embodiments, a sensor for detecting a threshold value of is provided. The sensor includes a deformable member with a mass detection area, an electrostatic actuator having first and second plates, the first plate being connected to the mass detection area, and a voltage source connected to each of the first and second plate. The operating voltage being proximate to a local bifurcation point of the electrostatic sensor for the first and second plates to pull-in together. Upon an external mass having the threshold value appearing on the mass detection area, the local bifurcation point of the electrostatic sensor is shifted such that the first and second plates will pull in to contact each other by movement of the deformable member to signal detection.