Some real-world applications of wireless sensor nodes

This paper presents two case histories of the use of wireless sensor Mote technologies. These are devices that incorporate communications, processing, sensors, sensor fusion, and power source into a package currently about two cubic inches in size networked autonomous sensor nodes. The first case discussed is the November, 2001, instrumentation of a blastinduced liquefaction test in Tokachi Port, Japan. The second case discussed is the dense-pakTM instrumentation of the seismic shaking test of a full-scale wood-frame building on the UCB Richmond shake table. The utility of dense instumentation is shown, and how it allows location of damage globally unseen. A methodology of interpreting structural seismic respose by Bayesian updating and extended Kalman filtering is presented. It is shown that dense, inexpensive instrumentation is needed to identify structural damage and prognosticate future behavior. The case studies show that the current families of Motes are very useful, but the hardware still has difficulties in terms of reliability and consistancy. It is apparent that the TinyOS is a wonderful tool for computer science education but is not an industrual quality instrumentation system. These are, of course, growing pains of the first incarnations of the Berkeley Smart Dust ideal. We expect the dream of easy to use, inexpensive, smart, wireless, sensor networks to become a reality in the next couple of years.