The Application And Designing Of The Low Power Wireless Strain Sensor

With the recognition of structural safety and the development of monitoring and inspection technique, Structural health monitoring (SHM) has already become an important research direction in civil engineering structures. And wireless sensor network is being developed as a research hotspot of SHM with such the characteristics as miniaturization, integration, low maintenance cost and a small quantity of installation time.In this paper., on the basis of sensing, information disposal and wireless communication technique, considering that the volume of traditional acquisition equipment is big,wiringlong and that the lead with high-precision is needed, the project and designing of low power wireless strain sensor applied for local monitoring is presented. Following is the main content of the paper:(1) Signal conditioning and sampling.: The structure's strain is sampled by using the traditional strain resistance as sensitive component. The voltage signal is sampled by using the in chip Analog-to-Digital Converter (ADC) of MSP430 after carrying through amplifying-filtering circuit.(2) Design of the radio frequency communication part: Sending and receiving the data by using nRF905.Design signal transmission circuit and finish the software program to realization signal transmission.(3) Design of antenna.: The general performance of small loop antennas is analyzed and a small loop antenna for wireless strain sensor is designed using resonance analysis method. The transformer matching method is used to design the matching network for antenna and RFIC. At last the feasibility of this antenna is proved through 3D electromagnetic simulation software HFSS.(4) Design of low power: Realization of low power consumption both in hardware and software, change the mode by interrupt to reailzation low power project.(5) Design of strain measurement program: Use VC's MSComm control to realize the data receiveing and showing.The system the paper given can not only be used in SHM, but also be used in other field universally, such as wireless water meter, wireless ammeter, wireless alarm, wireless key, home automation, and toy.A conclusion of the paper is made in the end. We also points out the flaw of the system, then presents the orientation of subsequent research work.