Implementing fiber optic sensors to monitor humidity and moisture

摘要

In a quest for fiber optic sensors that could monitor soil moisture, Blue Road Research implemented fiber Bragg grating sensors in such a way that they could detect humidity, soil moisture evaporation rates, and pressure changes from soil weight. These were then used to monitor soil in controlled flood tests to determine the moisture levels in a soil test bed. Fiber optic sensors seem well suited for humidity and soil moisture monitoring since they can easily be multiplexed with many sensors on one fiber line, and they have distinct longevity advantages that enable their use in applications involving wet environments, remote locations or long distances, electromagnetic interference, flammability, or other harsh environmental conditions that may degrade ordinary electronic sensors or their measurements. This paper describes the workings of a highly accurate optical humidity sensor that can be multiplexed on a fiber optic strand to monitor humidity that may lead to corrosion, soil moisture levels and changes, weather conditions, etc. as well as means to record such data.