Boosting the Sensing Fidelity of Low-Cost Hall Sensors

Magnetic sensors are the bedrock for various emerging applications, e.g., fine-grained tracking and tactile sensing. Among the many types of magnetic sensors, Hall sensors based on integrated magnetic concentrator (IMC) are the most popular ones thanks to their low-cost, ultra-compact, and three-axis features. However, due to the limited manufacturing precision, the crosstalk, i.e., additional noise caused by the uneven thickness of IMC, will be difficult to avoid. Our experiments reveal that crosstalk is a critical bottleneck that throttles high-accuracy sensing applications. To tackle this hindrance, we propose a novel solution called CrossFix — one-time-only, crosstalk correction. By performing a one-time rotation movement, one can calculate and mitigate the impact of the crosstalk. CrossFix tackles the crosstalk issue — thus is different from magnetic calibration methods (e.g., 8-shaped). The feasibility and robustness of CrossFix in different sensors and various real-world environments are verified by experiments. Empirical results demonstrate that CrossFix can correct 80% of the crosstalk under different interference. CrossFix can at least reduce the error rate by 23.53% and 40% in sensing virtual keystrokes and providing precise tactile feedback, respectively.