Passive Wireless Humidity Sensor for Building Monitoring

With people spending more time indoors, concerns about the impact of indoor environmental quality ¿ on human health, comfort, productivity, energy efficiency, building security, and respiratory disease control ¿ are rapidly increasing. Low-cost, reliable, and easy-deployment sensor systems are needed to monitor and control building environmental parameters. This project will develop an integrated, passive, wireless radio frequency (RF) sensing system to monitor humidity. The sensing platform and fabrication technology to be developed can be extended to a networked system for monitoring the building environment; by changing sensing materials, various conditions can be monitored, such as temperature, pollutant, flow rate, gases and bioagents. The system can be embedded into wallpapers because its multilayer thick film structure is low-cost, maintenance-free, and totally passive, and has a very long lifetime. In Phase I, several wireless humidity sensors were prototyped by employing a planar inductor, a capacitor resonant sensing platform, and various functional materials including porous ceramics. It was shown that multiple sensors could share a single reader, which would extend proposed sensor applications to multi-point or multi-parameter information sensing. Phase II will develop wireless sensor systems for commercial applications. Detailed objectives include developing a production-level prototype for wireless wallpaper humidity and temperature sensors, a readout system for multiple passive sensors, and a wireless sensor network implemented with industry standard protocols. Commercial Applications and Other Benefits as described by the awardee: The wireless passive sensors should be very useful for a remote-query environmental control strategy for increasing occupant comfort and decreasing energy consumption. A follow-on market also would exist in homeland security, providing protection against potential chemical and biological agent attacks in buildings.