Design of wireless monitoring system for health diagnosis of structural engineering

With the health diagnosis requirement increase of large-scale structural engineering, the author designed one wireless monitoring system which can be applied to different kinds of structure for health monitoring. The wireless monitoring system is a typical asteroid network, that is to say one receiver could control and receive many transmitters' action and data. One transmitter administrated one sensor. Through scan method, the receiver received signals from many sensors at the same time. Communication modules of transmitter and receiver were type of optional serial port communication module which is standard transparent serial port and supports standard intercommunication. For indoor shaking table experiments, communication module of type nRF401 can be used. The communication distance could achieve 25 m and expanse of communication was very cheap. For large-scale outdoor structural engineering testing, GPRS module based on common GSM communication network can be used. This kind of module has a very good communication quality and supports long distance communication. The CPU chip was AT89C55 which is the core of the data acquisition hardware of transmitter. And AT89C55 administrated and controlled all other peripheral chips. Such as starting AD converting of chip LTC1410 which is 12 bits Analogue to digital converter, saving data of one sample period in memory chip CY62256, transmitting data with the AD converting et al. Receiver was connected to computer of monitoring center through serial port. Then all the receiving data were processed at the same time by the computer. And the program has a view interface which could demonstrate all results and messages.