Title: BriMon: Design and Implementation of Railway Bridge Monitoring Application
Abstract: In this thesis we design a multi hop wireless sensor network based solution for the problem of structural bridge monitoring (of railway bridges). The problem presents several novel challenges. The real challenge here is to collect vibration data of a railway bridge, enabling on-demand analysis of the bridge. We not only provide an in-depth analysis of these challenges but also design a solution using multiple wireless technologies (IEEE 802.11 and IEEE 802.15.4 ). We take an application driven approach in providing a solution to the above problem. The implemented solution shows how the design choices dictated solely by the application are different from the general solutions that exist in the sensor network domain.
We design and implement protocols (routing and transport) on motes which are driven by the application. The transport protocol designed by us is NACK based and is used for reliable data transfer from all nodes to the base node. The routing algorithm determines the path that data follows. We further integrate our work with a fellow colleagues' synchronization mechanism and Wake on WLAN mechanism. We use synchronization mechanisms to synchronize readings of accelerometers placed at different points and for synchronized sleep and wakeup mechanisms and a novel Wake on WLAN mechanism for detection of arrival of a train. The transfer of data from the base node to the moving train is achieved using WiFi. We use off the shelf hardware to implement most of the solution, but where inexpensive off the shelf hardware is not available we build our own hardware. The solution has been implemented on Moteiv's Tmote-sky and the Soekris (single board computer). TinyOS and nesC has been used for programming the motes.
The challenges we have tackled in this work are one of a kind in this domain. There have been various works on monitoring of bridges and structures in India and abroad but most of them are wired solutions but a few are single hop wireless sensor network solutions which severely limit the size of the bridge being monitored. The architecture of the solution we have designed and implemented is unique to the best of our knowledge. The transfer of data to a moving train and detection of the arrival of the train are a new experiment in their own right.