A High‐Precision Triboelectric Rotational Sensor for Enhanced Low‐Speed Monitoring via Magnetic Modulation in Smart Fitness Systems

ABSTRACT Real‐time detection of low‐speed motion and precise monitoring of low‐intensity exercise are crucial for smart fitness systems. These capabilities enable continuous data acquisition, capture subtle motion variations for personalized guidance, and enhance training effectiveness while reducing the risk of injury. However, conventional rotational speed sensors often exhibit signal loss and limited responsiveness at low speeds, leading to inaccurate feedback and constraining the development of intelligent fitness devices. Therefore, this paper proposes a triboelectric rotational speed sensor (TRSS), which employs a coaxial reverse magnetic modulation transmission mechanism to enhance low‐speed monitoring, thereby overcoming low‐speed signal loss. The sensor enables real‐time detection of rotational speed in fitness equipment, and features a compact structure, doubled resolution, and high detection accuracy of 0.21 rad s −1 . Performance test indicates a sensitivity of 3.15 Hz (rad s −1 ) −1 , a linear correlation coefficient of 0.99892, and an average error of 1.19% in simulated tests, which demonstrates the capability of the sensor for accurate motion monitoring at low speeds. Furthermore, a triboelectric magnetic‐modulated rotational monitoring system (TMRMS) is developed and validated through cycling experiments, demonstrating excellent performance across a wide speed range. These findings highlight the strong potential of the system for advancing next‐generation smart fitness applications.