Research Of Environmental Information Monitoring Node Self-Powered Technology Based On Piezoelectric Power Generation

With the development of integrated circuits, micro electro-mechanical systems and sensor technology, wireless sensor network node as the core of the environmental monitoring information system is widely application in military, electricity, agriculture and other fields, brings great convenience for the intellectualized management. The wireless sensor network node is powered by electrochemical cell. Electrochemical cell has a large size and a limited life, it needs to be replaced regularly and some special devices are not easy to be replaced and the waste of materials and environmental pollution can not be ignored. Therefore, it is important to find a long-term and sustainable green energy for the development of environmental information monitoring field.In recent years, experts put forward to using the environmental energy around wireless sensor network nodes as the energy source for its power supply. Environmental energy including vibration energy, wind energy and solar energy. Energy is converted into electrical energy by the energy capture device and the electric energy is further processed by the energy management circuit, which can realize the power supply for the wireless sensor network node. The scheme has been deeply studied by researchers at home and abroad, it is considered that the scheme is feasible. However, there are many disputes in the design of energy capture, energy management and wireless sensor network node.This paper analyzes the international and domestic research status about the technology of environmental information monitoring nodes self-powered. Through using the power generation principle of vibration drive the piezoelectric cantilever vibrator, put forward a research program of environmental information monitoring node self-powered based on electric power. A green power supply module and a set of low power wireless environment information monitoring nodes are designed. It not only realizes the environment information collection, but also overcomes the defects of the existing power supply device, provides a green power for the monitoring equipment. At the same time, technical support is provided for the field of environmental information monitoring self-powered.The research work of this thesis includes the following aspects:(1) Through analysis on the theoretical knowledge of piezoelectric power generation, derived a mathematical model of cantilever beam type piezoelectric vibrator, design a multilayer cantilever beam energy capture device with quality block. Experimental results show that, at the vibration frequency of 44.1Hz, the energy capture device output maximum power, the frequency close to environment vibration frequency and the generating capacity can meet the requirements of the load.(2) Energy collecting chip LTC3588-1 and lithium battery charging chip LTC4071 is used to build energy harvest and storage circuit with a new nano power and low battery shutdown protection. The LTspice is used to simulation, The feasibility of the circuit is verified. Finally, experiments show that the circuit can output 3.3V stable voltage and meet the requirements of the power supply of wireless sensor nodes.(3) The MSP430G2553 microcontroller and APC240 wireless transmission module is used to design low power circuit for achieve the wireless monitoring of the slope of the building in the environment. Through overall system test,the results showed that at the mode of intermittent,it can realize self-powered wireless monitoring of the objects in the environment.