An energy harvesting device includes a MEMS composite transducer. The MEMS composite transducer includes a substrate. Portions of the substrate define an outer boundary of a cavity. A MEMS transducing member includes a beam having a first end and a second end. The first end is anchored to the substrate and the second end cantilevers over the cavity. A compliant membrane is positioned in contact with the MEMS transducing member. A first portion of the compliant membrane covers the MEMS transducing member. A second portion of the compliant membrane is anchored to the substrate. The compliant member is configured to be set into oscillation by excitations produced externally relative to the energy harvesting device.