Energy harvesting devices for low frequency applications

An energy harvesting device, comprising:

• a strip defining a longitudinal axis and having two opposing planar surfaces substantially larger than remaining surfaces of the strip;
• at least one cantilever having one end coupled to the strip and a mass disposed at an opposing end of cantilever, wherein the cantilever extends outwardly from the strip;
• a piezoelectric material disposed on at least one surface of the cantilever;
• a first wall disposed adjacent to one of the planar surfaces of the strip and a second wall disposed adjacent to the other of the planar surface of the strip, wherein the strip exhibits a snap-through event in response to a force applied axially thereto and the first and second walls laterally constrain the snap-through event of the strip.

An energy harvesting device, comprising:

• a buckling member having a longitudinal axis and configured, in response to a force applied axially thereto, to exhibit snap-through events amongst three or more stationary positions;
• at least one cantilever having one end coupled to the buckling member and a mass disposed at an opposing end thereof, the cantilever extends outwardly from the buckling member and includes a piezoelectric material disposed on a surface thereof;
• and
• a constraining member positioned adjacent to the buckling member along the longitudinal axis of the buckling member and in contact with the buckling member in each of the three or more stationary positions such that the buckling member is compressed along the longitudinal axis in each of the three or more stable positions.