Exploiting Nano Aerial Vehicles as Sensor Nodes for Wireless Vibration Monitoring

Monitoring critical infrastructures has become an imperative need in modern society. However, in some circumstances, the physical installations of sensors is hampered by the harshness of the target scenario, preventing human intervention. In this work, we aim at offering a low-cost, non-invasive and innovative solution to vibration-based inspection based on Nano Aerial Vehicles (NAVs). The idea is to realize a Wireless Sensor Network (WSN) in which each NAV, once anchored, acts as a sensor node by exploiting its inertial sensing unit for vibration data sensing. We started from a commercial NAV, i.e., the “Crazyflie 2.1” platform, and expanded its functionalities at three different levels: i) hardware, by prototyping an ultra-low-weight (less than 8 g) energy harvester (EH) necessary to expand the battery duration, ii) firmware, by introducing low-power functioning modes and features tailored for a sensor node for vibration inspections, and iii) software, by developing a custom PC client for its control. Results demonstrate that it is possible to convert a NAV into a Sensor Node (SN) with functionalities including i) an output data rate up to 400 Hz, thus overcoming the bottleneck of the flight telemetry rate limited to 100 Hz and ii) complete energy autonomy thanks to the 125 mW of power daily harvested by the designed EH.