PiezoStep: Automation of Auxiliary Safety Control Devices by Harvesting Freely Available Kinetic Energy

This paper presents the design, fabrication, and electromechanical evaluation of PiezoStep, a kinetic energy-harvesting floor tile utilizing Lead Zirconate Titanate (PZT) ceramic piezoelectric transducers. Rather than directly powering high-wattage appliances from piezoelectric elements, the system implements a novel self-powered triggering architecture. The mechanical impact of a human footfall generates a rectified DC pulse that powers local diagnostic LEDs while simultaneously tripping the isolated trigger input of a digital time-delay relay control module to switch external 120 V AC mains power. Experimental validation using a hand-fabricated 24.5 cm × 24.5 cm dual-plate chassis with an engineered 5-spring suspension matrix demonstrated transient AC peaks up to 35.5 V under a 100 kg load and 13.0–18.2 V under a standard 50 kg human footprint. Conditioned through a solid-state 1N4001 full-wave bridge rectifier and buffered across a 100 µF capacitor, the system achieved a rectified DC output of 1.9 V at a 25 kg activation threshold and up to 16.4 V at 100 kg, storing up to 13.4 mJ of energy. The design serves as a practical, scalable proof-of-concept for autonomous, pedestrian-triggered safety infrastructure in high-density transit corridors.