Microelectromechanical systems (mems) inertial sensors with energy harvesters and related methods

A microelectromechanical system (MEMS) apparatus comprising:

• a substrate;
• a piezoelectric energy harvester comprising:
• a beam coupled to the substrate, wherein at least a portion of the beam comprises a piezoelectric material layer;
• a proof mass coupled to the beam;
• and
• an inertial sensor comprising:
• a first electrode coupled to the proof mass;
• and
• a second electrode coupled to the beam.

A method for sensing motion using a microelectromechanical system (MEMS) apparatus, the method comprising:

• converting, to electric energy, vibrational energy of a proof mass coupled to a substrate by sensing mechanical stress in a piezoelectric material layer formed between the proof mass and the substrate;
• with a sense circuit, sensing motion of the proof mass relative to the substrate along at least one axis;
• and
• powering the sense circuit at least in part with the electric energy.