Low-Cost Dielectric Sheets for Large-Area Floor Sensing Applications

Sensitivity response is a critical parameter that decides the domain of dielectric materials to be implemented as piezocapacitive sensors for low- or high-pressure sensing applications. Here, we have clarified the sensitivity response behavior of three low-cost dielectric materials, two biodegradable paperboards, and one acoustic polymeric foam. The devices are fabricated in the form of a metal-insulator-metal structure, and the capacitive response of the devices is measured using the charge extraction by linearly increasing voltage technique. The sensitivity response curve (ΔC/C _o vs. pressure) reveals that the paperboard materials are sensitive enough to detect low-pressure regimes (45 kPa), whereas the acoustic foam is quite promising for high-pressure monitoring (above 150 kPa). Using a multiplexer circuit, we demonstrated the sensitivity response via 2 by 2 matrix structure both as a steady-state and transient response. Our results show that the passive matrix structure interference between different pixels can be minimized after increasing the spacing between electrodes strip. Finally, a full-scale demonstrator (dimension 120 cm × 400 cm) with a 2 × 8 matrix structure laminated under floor tiling has been demonstrated. We show how such a floor sensor utilizing the low-cost substrates can be used to recognize single-stepping, walking, and falling.