Study of Pressure Distribution in Floor Tiles with Printed P(VDF:TrFE) Sensors for Smart Surface Applications

Abstract

Pressure sensors integrated in surfaces, such as the floor, can enable movement, event, and object detection with relatively little effort and without raising privacy concerns, such as video surveillance. Usually, this requires a distributed array of sensor pixels, whose design must be optimized according to the expected use case to reduce implementation costs while providing sufficient sensitivity. In this work, we present an unobtrusive smart floor concept based on floor tiles equipped with a printed piezoelectric sensor matrix. The sensor element adds less than 130 µm in thickness to the floor tile and offers a pressure sensitivity of 36 pC/N for a 1 cm2 pixel size. A floor model was established to simulate how the localized pressure excitation acting on the floor spreads into the sensor layer, where the error is only 1.5%. The model is valuable for optimizing the pixel density and arrangement for event and object detection while considering the smart floor implementation in buildings. Finally, a demonstration, including wireless connection to the computer, is presented, showing the viability of the tile to detect finger touch or movement of a metallic rod.

Vibration Energy Harvesting with Printed P(VDF:TrFE) Transducers to Power Condition Monitoring Sensors for Industrial and Manufacturing Equipment

“…The substrate was modeled as an isotropic liner elastic material, while the piezoelectric layer used an orthotropic model with COMSOL's in‐built piezoelectric coupling equations following our previous works. [ 35,36 ]…”

“…In the simulation, the electrodes are only included as boundary conditions for the voltage field, while P(VDF:TrFE) is implemented as an orthotropic linear elastic piezoelectric material, as shown in previous works. [35,36] The change in local piezoelectric polarization, and therefore surface charge density, is proportional to the local strain component parallel to the poling direction (z-direction). Thus, in order to avoid charge cancelations, the strain field amplitude must have the same sign in the area covered by the electrode (~defined by L p ).…”

“…The substrate was modeled as an isotropic liner elastic material, while the piezoelectric layer used an orthotropic model with COMSOL's in-built piezoelectric coupling equations following our previous works. [35,36] An isotropic damping parameter of η = 0.015 was used to obtain realistic values at resonance. As electrical boundary conditions, the voltage at bottom was set to 0 V. On the top boundary, a terminal boundary condition was set.…”