strength of the magnet 301 fig4 a illustrates one of the embodiments of the proposed sensor design the layout of the sensor shown in fig4 a is very much similar to what is shown in fig2 a a bottom hard magnet 401 provides expelling magnetostatic force on the floating magnet 406 in the tube 403 to balance its gravity the proposed sensor design shown in fig2 a detects the change rate of the magnetic flux within the magnetic flux pickup coil 218 the design shown in fig4 a is quite noticeably different from that shown in fig2 a the solid magnetic field transducer 404 is used to detect the magnetic field strength regardless whether the magnetic field varies or not as long as the frequency of magnetic field variation is below a threshold value e g ghz which is well above the frequency we are interested in during fall event or the proposed applications the magnetic field strength sensed by the solid magnetic field transducer 404 has a close correlation with the exact position of the floating magnet 406 in the tube 403 once the relative position of the transducer 404 to the tube 403 is fixed any movement of the floating magnet 406 inside the tube 403 will change the magnetic field strength that can be detected by the solid magnetic field transducer 404 the solid magnetic field transducer 404 can be a hall sensor a magneto impedance mi sensor a reed sensor an anisotropic magnetoresistive sensor amr a giant magnetoresistive sensor gmr.