Abstract: A portable electronic device includes a motion sensor and a controller. The motion sensor detects an alternating signature motion of a limb of the user about a virtual axis corresponding to the limb. The motion sensor may be an accelerometer capable of detecting three dimensional acceleration. The accelerometer detects acceleration along X, Y and/or Z axes, in which acceleration peaks of the X and Z axes alternate with each other and acceleration of the Y axis remains substantially steady relative to the X and Y axes. The portable electronic device controls at least one function based on the detected alternating signature motion of the limb and/or acceleration along the X, Y and/or Z axes.

Abstract: A pedometer or other stride-detection device (304) can record the number of strides, and the frequencies of those strides, during a running or other session using a detector (306). The device (304) can report an estimated total elapsed distance (318) at the end of the session, based on the number and estimated lengths of each stride. The reported distance can be calculated using estimates for stride lengths at various frequencies based on a user profile (210), as well as a correction value table (308) and a frequency count table (202). At the end of each session, a corrected distance can be received by user input based on a treadmill display, or other means. A frequency-based correction factor can be updated based on an error ratio of the corrected and reported distances, which can be limited by a correction factor limit and distributed based on a stride frequency probability distribution.

Abstract: A portable electronic device includes a motion sensor and a controller. The motion sensor detects an alternating signature motion of a limb of the user about a virtual axis corresponding to the limb. The motion sensor may be an accelerometer capable of detecting three dimensional acceleration. The accelerometer detects acceleration along X, Y and/or Z axes, in which acceleration peaks of the X and Z axes alternate with each other and acceleration of the Y axis remains substantially steady relative to the X and Y axes. The portable electronic device controls at least one function based on the detected alternating signature motion of the limb and/or acceleration along the X, Y and/or Z axes.