Vibration sensors

A vibration sensor, comprising:

• a vibration assembly, the vibration assembly including a mass element and an elastic element, and the mass element being connected to the elastic element;
• a first acoustic cavity, the elastic element constituting one of sidewalls of the first acoustic cavity, and the vibration assembly vibrating to make a volume of the first acoustic cavity change in response to an external vibration signal;
• an acoustic transducer, the acoustic transducer being in communication with the first acoustic cavity and the acoustic transducer generating an electrical signal in response to a volume change of the first acoustic cavity;
• a buffer, the buffer limiting a vibration amplitude of the vibration assembly, wherein the acoustic transducer has a first resonance frequency, the vibration assembly has a second resonance frequency, and the second resonance frequency is smaller than the first resonance frequency;
• and
• a housing, wherein the housing receives the external vibration signal and transmits the external vibration signal to the vibration assembly, the housing forms an acoustic cavity, the vibration assembly is located in the acoustic cavity and separates the acoustic cavity into the first acoustic cavity and a second acoustic cavity, the elastic element is disposed opposite to the acoustic transducer, at least one convex structure is disposed on a side of the elastic element facing the first acoustic cavity, the elastic element drives the at least one convex structure to move in response to the external vibration signal, and the movement of the at least one convex structure changes the volume of the first acoustic cavity.