A Wearable Piezoelectric‐Electromagnetic Hybrid Harvester Based on an M‐Shaped Beam for Self‐Powered Gait Monitoring

To address sustainable power challenges in continuous human motion monitoring, this study proposes a piezoelectric‐electromagnetic wearable harvester (PEW‐HD) based on M‐shaped beams for ultra‐low‐frequency biomechanical piezoelectric energy harvesting and dual‐source motion detection. Compared with traditional cantilevers, the M‐shaped beam lowers natural frequencies by up to 65% and reduces structural stiffness. This exceptional flexibility enables high sensitivity to human arm‐swinging excitations, maximizing power output. Meanwhile, the mutual movement between excitation magnets and the coil generates distinct electrical waveforms to identify the motion state. Under optimal structural parameters (six excitation magnets, 6 mm magnet spacing, 1.5 Hz frequency, and 90 g counterweight), the device achieves a peak‐to‐peak output voltage of 79.6 V and a maximum power of 26.66 mW. The device can provide stable power input for 90 LEDs or a temperature and humidity sensor. Furthermore, combined with the long short‐term memory (LSTM) model and dual‐source detection of piezoelectric and electromagnetic signals, it accurately distinguishes the wearer's fast and slow walking patterns. The recognition accuracy of the training set and the test set reaches 93.75% and 95.83%, respectively. It provides an effective, eco‐friendly solution for sustainable micro‐energy harvesting, battery‐free wearable electronics, and self‐powered kinematic monitoring.