A smart node architecture for underwater monitoring of sensor networks

This paper describes a wired addressing architecture of distributed sensors for monitoring real-time in situ pressure variations in underwater environment. Limits of isolated sensors and drawbacks of acoustic communication are overcome, and an application to the inspection of a submerged structure is made feasible. The prototype sensor is a Kapton®-based three-layered structure. We fabricated a 0.18 μm CMOS mixed-mode System on Chip (SoC) as a prototype and a five-pad Chip on Board (COB) for unobtrusive monitoring. Testing sessions in aquatic environment have been carried on, and the dependence of the capacitance on pressure variation is shown when a linear pressure variation is exerted. An experimental result in a turbulent operating condition is reported too.