A WIRELESS SENSOR NETWORK BOARD FOR ENVIRONMENTAL MONITORING USING GNSS AND ANALOG TRIAXIAL ACCELEROMETER

Wireless Sensor Networks (WSNs) have attracted an increasing attention in recent years because of the large number of potential applications. They are used for collecting, storing and sharing data, for monitoring applications, surveillance purposes and much more. On the other hand GNSSs are used in various systems devoted to monitor different atmospheric parameters and to trace displacements of landslides and glaciers in severe environmental conditions and in all weather situations. A first example of low cost DGPS wireless sensor network was installed in 2009 on a serac located at 4100 m above a populated area in the Aosta Valley, Italy, and it is still operative. This work presents an evolution of the WSN node used in that systems with improved functionalities and flexibility. The electronic board developed as a multipurpose board to be used in different WSNs, has been completely redesigned as an open system in order to reduce its sizes and to be configured by only varying the firmware on the microcontroller. It allows different interfaces and is equipped with a recovery system, guaranteed by a watchdog chip which continuously monitor the onboard microcontroller. The board is equipped with both a GNSS module and an analog triaxial accelerometer in order to merge GNSS raw data and accelerometer data to keep track of both fast events and slow events. A free open source operative system has been ported on the microcontroller in order to perform multiple operations and to manage the communications between the network nodes with improved efficiency. The board firmware can be modified in real time using a custom bootloader to avoid difficult maintenance operations.