Distributed Passive Sensor for Moisture Sensing in Structures

Moisture in buildings is considered as a severe issue for the deterioration of the consistency of structural materials, as well as for the well-being of the inhabitants. The relevance of the topic increases with the trend of increased application of natural materials in construction, e.g. in timber based construction. The requirements for a moisture sensing system are in the need to cover a large area, simple installation (no cables) and a long lifetime. Hence classical moisture probes are not suitable for distributed moisture sensing. In this paper we present a distributed passive sensor approach for moisture sensing in structures. A sensor network is formed by means of coupled resonance circuits, where each individual sensor is used to detect moisture and to distribute the information of the other sensors. The individual sensor element is realized by means of wire traces only, enabling an inherently robust design suitable for harsh environments. We will present the design of the sensor elements and the network interactions by means of a sensor model and demonstrate the capability of the approach by means of measurements.