Patent ID: 7571847
Filing Date: 2009-08-11
Classification: A61B,G01C

Abstract:
1. An apparatus for measuring a number of footsteps, the apparatus comprising: a terrestrial magnetism sensing unit which outputs digital values of at least two of an X-axis, a Y-axis and a Z-axis, within a predetermined sampling time interval according to movement of a body; a reference digital value generator which generates a reference digital value based on N digital values of each axis output from the terrestrial magnetism sensing unit, (N−1) digital values of each axis output from the terrestrial magnetism sensing unit in one sampling time interval before the N digital values are output, and (N−2) digital values of each axis output from the terrestrial magnetism sensor in one sampling time interval before the (N−1) digital values output; a reference axis selector which searches for an N digital value of an axis having a maximum amplitude in a predetermined period among the N digital values of each axis output and selects an axis having the maximum amplitude as a reference axis; a digital value determiner which determines whether the N digital value of the reference axis is larger than a reference digital value of the reference axis by a predetermined value; and a controller which determines the movement of the body is an ascending movement of one footstep, if the N digital value is larger than the reference digital value by a predetermined value.