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A compact cell phone size radio frequency (ZigBee) wireless strain measurement sensor system to measure the
structural strain deformation was developed. The developed system provides an accurate strain measurement data
stream to the Internet for further Diagnostic and Prognostic (DPS) correlation. Existing methods of structural
measurement by strain sensors (gauges) do not completely satisfy problems posed by continuous structural health
monitoring. The need for efficient health monitoring methods with real-time requirements to bidirectional data flow
from sensors and to a commanding device is becoming critical for keeping our daily life safety. The use of full-field
strain measurement techniques could reduce costly experimental programs through better understanding of material
behavior. Wireless sensor-network technology is a monitoring method that is estimated to grow rapidly providing
potential for cost savings over traditional wired sensors. The many of currently available wireless monitoring methods
have: the proactive and constant data rate character of the data streams rather than traditional reactive, event-driven
data delivery; mostly static node placement on structures with limited number of nodes. Alpha STAR Electronics'
wireless sensor network system, ASWN, addresses some of these deficiencies, making the system easier to operate.
The ASWN strain measurement system utilizes off-the-shelf sensors, namely strain gauges, with an analog-to-digital
converter/amplifier and ZigBee radio chips to keep cost lower. Strain data is captured by the sensor, converted to
digital form and delivered to the ZigBee radio chip, which in turn broadcasts the information using wireless protocols
to a Personal Data Assistant (PDA) or Laptop/Desktop computers. From here, data is forwarded to remote computers
for higher-level analysis and feedback using traditional cellular and satellite communication or the Ethernet
infrastructure. This system offers a compact size, lower cost, and temperature insensitivity for critical structural
applications, which require immediate monitoring and feedback.
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