Multimodal Intelligent Flooring System for Advanced Smart-Building Monitoring and Interactions.

The floor constitutes one of the largest areas within a building with which users interact most frequently in daily activities. Employing floor sensors is vital for smart-building digital twins, wherein triboelectric nanogenerators demonstrate wide application potential due to their good performance and self-powering characteristics. However, their sensing stability, reliability, and multimodality require further enhancement to meet the rapidly evolving demands. Thus, this work introduces a multimodal intelligent flooring system, implementing a 4 × 4 floor array for multimodal information detection (including position, pressure, material, user identity, and activity) and human-machine interactions. The floor unit incorporates a hybrid structure of triboelectric pressure sensors and a top-surface material sensor, facilitating linear and enhanced sensitivity across a wide pressure range (0-800 N), alongside the material recognition capability. The floor array is implemented by an advanced output-ratio method with minimalist output channels, which is insensitive to environmental factors such as humidity and temperature. In addition to multimodal sensing, energy harvesting is co-designed with the pressure sensors for scavenging waste energy to power smart-building sensor nodes. This developed flooring system enables multimodal sensing, energy harvesting, and smart-sport interactions in smart buildings, greatly expanding the floor sensing scenarios and applications.