Tactile Sensor for Subcutaneous Vocal Organ Vibrations Inspired by Otolith Cilia

Tactile sensing of subcutaneous organ vibrations provides a promising route toward human–machine interfaces and wearable diagnostics, particularly for voice rehabilitation and silent-speech communication. Here, we present a bioinspired piezoelectric vibration sensor that mimics the graded stiffness and stress-based transduction mechanism of otolithic cilia in the human vestibular system. The device consists of a trapezoidal cantilever array with tip inertial masses, fabricated through a hybrid stereolithography 3D printing and laser micromachining process for rapid prototyping without cleanroom facilities. Finite-element modeling and experimental measurements demonstrate a fundamental resonance near 1.2 kHz, a 5% flat-bandwidth of 350 Hz, and an in-band charge sensitivity of 3.17 pC/g. A wearable proof-of-concept test further verifies the sensor’s ability to reproducibly distinguish phoneme-specific vibration patterns in both time and frequency domains. This work establishes a foundation for bioinspired tactile sensing front-ends in wearable voice interfaces and other intelligent diagnostic systems integrated with machine-learning algorithms.