Abstract
Accurate tracking of body joint angles is essential for rehabilitation, sports science, AR/VR, and health monitoring. Existing solutions — cameras, IMUs, and flex sensors — all suffer from major limitations: occlusion, cumulative drift, or prohibitive cost. MagDot introduces a new approach using pairs of passive magnets attached across a joint, where the magnetic field geometry encodes the angle between the two limb segments.
MagDot is the world's first drift-free, low-cost wearable joint angle tracking system. It achieves tracking accuracy of 2.72° at the elbow, 4.14° at the knee, and 4.61° at the shoulder — validated against a nine-camera professional motion capture system. With only 98 mW power consumption, a single charge supports a full day of continuous use.
Key Results
BibTeX
@article{chen2024magdot,
title = {MagDot: Drift-free, Wearable Joint Angle Tracking at Low Cost},
author = {Chen, Dongyao and Luo, Qing and Chen, Xiaomeng and Wang, Xinbing and Zhou, Chenghu},
journal = {Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (IMWUT)},
volume = {7},
number = {4},
articleno = {150},
year = {2024},
doi = {10.1145/3631423},
publisher = {ACM}
}