Multi-hop wireless crack measurement for control of construction vibrations

Miniaturized, multiple position, multi-hop, wireless instrumentation is now a reality and this paper describes development and testing of such a system to monitor crack response. These wireless systems will facilitate measurement of crack width changes in structures in order to assess structural health of critical infrastructure components such as fracture critical bridges or structures near construction. A low power consumption potentiometer displacement transducer and multi-hop communication algorithm allow this system to operate up to a year with 2 AA size batteries. The system described herein is capable of measuring long-term crack displacement along with temperature and humidity. A field test of the system is described that includes operation of multiple, remote data motes as well as back casting communication necessary to autonomously display crack response in a graphical format over the Internet. This system in another form won third place honors in the 2005 Crossbow Smart Dust Challenge, which represented the best executable ideas for wireless sensor networks that demonstrate how it is used, programmed and deployed to positively impact society.