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The U.S. Army Engineer Research and Development Center (ERDC) has developed an underwater wireless modem using low frequency (LF) electromagnetic communication with application to Structural Health Monitoring (SHM) and nondestructive evaluation (NDE) of partially submerged large civil infrastructure, such as navigational locks. Environmental constraints with commonly used underwater wireless communication techniques have motivated the investigation of electromagnetic telemetry. The ongoing research has resulted in an integrated hardware solution with current focus on software development, sensor integration, and deployment testing. Ultimately, the underwater telemetry modems are expected to provide a method for The U.S. Army Corps of Engineers to improve data collection and process control for monitoring of structures in our navigable inland waterways. This paper highlights the recent and ongoing progress of the project and anticipates possible applications of the technology to other extreme environments.

An embedded strain gage data logger has been developed by the Engineer Research and Development Center (ERDC) to facilitate data collection for an in-situ experiment investigating the strain and acceleration encountered by the paddlefish rostrum as it swims. This unique application has required a focus on reducing the size, weight, and power (SWaP) of the system. The accomplishments explained in this paper are the integration of a custom strain gage amplifier with a microcontroller and the verification of a linear relationship of the strain measured by this device with a calibrated professional desktop system. The mean and standard deviation errors between the expected values of the calibrated commercial system and the data logger from this experiment are −7/.7 × 10−14 μϵ and 14.3 μϵ respectively.