The authors are developing a flexible sensor network with numerous potential uses. This paper presents one constructive application of the sensor integration platform and network. The theory of operation is as follows. Multiple sensing/processing nodes are scattered about a 30-mile radius on land. Each node has the capability to handle up to a few different sensors based on user needs. The nodes operate autonomously while continuously acquiring data and process the information locally. The information deemed relevant to the system operator is uplinked to a base station at optimal intervals. Further data collection takes place at the base station where an operator can take appropriate action. Communication between the base station and nodes is based upon the emerging IEEE 802.16 standard. This enables broadband level information transfer at ranges capable of covering entire metropolitan areas.
The application discussed in this paper is a homeland security monitoring system. This system would make use of a variety of nodes to collect data from surveillance cameras at border crossings and high value assets, water contamination sensors, weather sensors, and other sensors the user sees necessary. A technical description of the system architecture, its benefits, and limitations will be included. The utility of the 802.16 standard will also be incorporated in the paper.
It is possible to dramatically improve the performance, reliability, and maintainability of vehicles and other similarly complex equipment if improved sensing and diagnostics systems are available. Each year military and commercial maintenance personnel unnecessarily replace, at scheduled intervals, significant amounts of lubricant fluids in vehicles, weapon systems, and supporting equipment. Personnel draw samples of fluids and send them to test labs for analysis to determine if replacement is necessary. Systematic use of either on-board (embedded) lubricant quality analysis capabilities will save millions of dollars each year in avoided fluid changes, saved labor, prevented damage to mechanical components while providing associated environmental benefits. This paper discusses the design, the manufacturing, and the evaluation of robust optical sensors designed to monitor the condition of industrial fluids. The sensors reported are manufactured from bulk fused silica substrates. They incorporate three-dimensional micro fluidic circuitry side-by-side with three-dimensional wave guided optical networks. The manufacturing of the optical waveguides are completed using a direct-write process based on the use of femtosecond laser pulses to locally alter the structure of the glass substrate at the nano-level. The microfluidic circuitry is produced using the same femtosecond laser based process, followed by an anisotropic wet chemical etching step. Data will be presented regarding the use of these sensors to monitor the quality of engine oil and possibly some other vehicle lubricants such as hydraulic oil.