Envisioned-Empowered Wind-Dispersal Coded Flier System With Passive RFID Infrastructure: Experimental Evaluation

The concept of sensing environmental parameters in the air has recently gained attention through drone-based, insect-based, or wind-dispersal-based mechanisms. Interestingly, wind-dispersal mechanisms require no driving mechanical system and are solely powered by wind energy to scan and sense selected areas of interest. In this paper, we propose a low-cost system of wind-dispersal fliers that are coded and localized based on passive UHF RFID technology. For the flier's mechanical design, a 2D structure is first designed, inspired by winged seeds, consisting of four wings with asymmetrical cross-sections to provide better mechanical stability during descent and enhanced integration with UHF RFID tags. The 2D structure is then transformed into 3D configurations by tilting the blades at different angles and utilizing different curvatures. By introducing porosity in the 3D design and optimizing the blades' angles and curvature, a low terminal velocity of 1.64 m/s is achieved based on measurements. The fliers are fabricated using Laser Sintering from Polyamide 12 (PA12) with a low thickness of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$200\,\,\mu \text {m}$</tex-math></inline-formula>. For system demonstration, four distributed reader antennas are employed to interrogate a coded flier equipped with a passive RFID tag that uses a UHF Gen2 chip. For system evaluation, various scenarios encompassing distinct tags and flier trajectories are evaluated using a Received Signal Strength Indicator (RSSI) algorithm, specifically tailored to meet our system requirements. The average localization error varies across the evaluated scenarios, providing insights into the performance of the system under different conditions.