The invention is a system incorporating a self-tuning resonator and method of self-tuning a resonator within a system. In one embodiment, a method of powering a system with energy harvested from a vibrating surface includes receiving a first mechanical energy at a first driving frequency from the vibrating surface, transferring the received first mechanical energy to a suspended structure within the system, vibrating the suspended structure with the transferred first mechanical energy, passively adjusting the resonant frequency of the suspended structure to a first resonant frequency associated with the first driving frequency by moving a movable mass in response to the movement of the suspended structure, vibrating the adjusted suspended structure with the transferred first mechanical energy, generating electrical energy using the vibrations of the adjusted suspended structure, and powering the system with the generated electrical energy.