  Step-counting has been widely implemented in wrist-worn devices and is
accepted by end users as a quantitative indicator of everyday exercise.
However, existing counting approach (mostly on wrist-worn setup) lacks
robustness and thus introduces inaccuracy issues in certain scenarios like
brief intermittent walking bouts and random arm motions or static arm status
while walking (no clear correlation of motion pattern between arm and leg).
This paper proposes a low-power step-counting solution utilizing the body area
electric field acquired by a novel electrostatic sensing unit, consuming only
87.3 $\mu$W of power, hoping to strengthen the robustness of current dominant
solution. We designed two wearable devices for on-the-wrist and in-the-ear
deployment and collected body-area electric field-derived motion signals from
ten volunteers. Four walking scenarios are considered: in the parking
lot/shopping center with/without pushing the shopping trolley. The
step-counting accuracy from the prototypes shows better accuracy than the
commercial wrist-worn devices (e.g.,96% of the wrist- and ear-worn prototype
vs. 66% of the Fitbit when walking in the shopping center while pushing a
shopping trolley). We finally discussed the potential and limitations of
sensing body-area electric fields for wrist-worn and ear-worn step-counting and
beyond.
