Mechanically-triggered self-powered triboelectric sensor platform with arbitrary-to-constant mechanical input conversion

The development of self-powered environmental and chemical sensing systems capable of reliable operation under irregular mechanical inputs is essential for realizing practical and autonomous electronics. Here, we present a mechanically-triggered, self-powered triboelectric sensor platform that overcomes this limitation through arbitrary-to-constant mechanical input conversion. The platform employs a magnetic latching mechanism that stores elastic potential energy in a cantilever coupled with a flexible sagged film and releases it once an external displacement exceeds a predefined threshold. Once released, the cantilever exhibits a high-frequency free vibration at its natural frequency of approximately 52.6 Hz and a consistent amplitude of 8.2 mm initially, independent of the input amplitude range of 25-35 mm and frequency range of 0.1-1 Hz. This process produces stable electrical outputs through the triboelectric energy conversion mechanism with less than 9.6% deviation across the tested input conditions. To demonstrate the versatility of this platform, we fabricated two types of active sensors, a humidity sensor based on charge dissipation in a hydrolyzed electrospun polyethylene terephthalate layer and an ammonia sensor utilizing impedance modulation of a polyaniline layer. Both devices exhibited highly stable, mechanical input-independent performance, confirming the platform's adaptability to different sensing mechanisms and materials. This mechanically triggered architecture provides a robust structural solution to an often overlooked source of signal ambiguity in self-powered sensors, offering the potential for reliable, portable, and human-interactive sensing applications.