Earable and Wrist-worn Setup for Accurate Step Counting Utilizing Body-Area Electrostatic Sensing

TL;DR

This paper introduces a low-power electrostatic sensing method for more accurate step counting in wearable devices, outperforming commercial wrist-worn trackers especially in challenging scenarios like pushing a trolley.

Contribution

It presents a novel body-area electrostatic sensing approach and wearable prototypes for ear and wrist, improving step-counting robustness over existing solutions.

Findings

Achieved 96% accuracy in step counting, surpassing 66% of commercial devices.

Designed wearable devices with ultra-low power consumption of 87.3 μW.

Demonstrated effectiveness in various real-world walking scenarios.

Abstract

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.