Woo! We finished our senior project. We have created a system of wireless accelerometers to measure the structural health of buildings. See below for some pictures and downloads.
Abstract: A Structural Health Monitoring (SHM) System, relying on identification of changes to a structures resonant frequency to recognize potential structural damage and provide alerts, is designed and implemented. A module, using a 3-axis MEMS-based digital accelerometer, capable of measuring and wirelessly transmitting frequency data to a remote computer is made. A test apparatus, consisting of a cantilever-beam and a mechanical device capable of producing up to 20 Hz frequency vibrations in the beam, is constructed to verify the modules readings. The beam is subjected to ambient vibrations and the module monitors its tip acceleration. The remote computer calculates a Fast Fourier Transform to distinguish resonant frequencies on a continuous time basis, and a user interface provides alerts when natural frequency changes considerably.