A sensing apparatus utilizing film bulk acoustic resonators (FBARs). The film bulk acoustic resonator has a bulk acoustic wave velocity (Vb) and a corresponding resonant frequency (f). When the FBAR is subjected to a force such as acceleration, g-force or an air pressure, the bulk acoustic wave velocity changes to obtain a frequency downshift (Δf) in response to deformation caused by the force. A magnitude of the force is then obtained by calculating the frequency downshift (Δf).