An apparatus comprising a mechanical-to-electrical energy converting device utilizes an array of microfluidic droplets in association with a planar electrode and separated by a dielectric layer to form a capacitive structure. An elastic spacer is also disposed between the planar electrode and array of droplets, such that as the spacer is compressed, the contact area of the droplets and the dielectric is increased—increasing the total capacitance value. Periodic changes in the force applied to the elastic spacer (such as associated with vibrational motion) creates a periodic change in the capacitance value, generating an electrical current flow between the planar electrode and array of conductive droplets.