Research And Implementation Of Wireless Sensor Network Nodes Based On Energy Harvesting

Being recognized as one of the most important technologies of the21st century, wireless sensor network technology has been concerned and researched widely by domestic and foreign scholars and enterprises. Wireless sensor network technology has irreplaceable advantages in solving monitoring, communication, management and rescue of some special occasions and environment. Energy consumption and energy supply are two key issues which must be solved in development process of wireless sensor network application technology. However, the wired energy and disposable batteries of traditional nodes limit the wide application and depth expansion of wireless sensor networks. With the research and development of ambient energy harvesting technology, the nodes with ambient energy harvesting capabilities will provide complete energy solutions applied in a specific area of wireless sensor networks, therefore the research of nodes with energy harvesting is an urgent practical work and has a great significance.In this paper, as solar and wind energy being investigative background, the collection of solar and wind energy, energy storage circuit and node management strategies have been researched. Based on existing technology, the problems in the application of wireless sensor networks are to be solved, and then exploratory study of wireless sensor network applications in the areas which are plenty of ambient energy is launched. The following are major achievements achieved:1. Three kinds of solar energy harvesting circuits collecting solar energy are designed and implemented, which are different circuit solutions suitable for different nodes of energy tactics. Furthermore, the different properties of lithium batteries and ultra-capacitors are studied for energy storage. In the process of circuit design, the low power of energy harvesting circuit and the efficiency the whole circuit system are fully being taken into account, and the collection efficiency of the three circuits have all reached more than90%. Meanwhile, coordinator node using wind power and lead-acid batteries to store energy is designed, and remote wireless data platform is placed on the nodes to achieve the collection and management of data.2. The weak current testing system is designed and implemented to provide an effective mean for low-power circuit debugging. Weak current testing which uses logarithmic amplifier as the core device, is implemented the current measurement between10nA～1mA by design three ranges. It can meet accurate measurement of power consumption of nodes in sleep state.3. The wireless sensor network test platform in star structure is built for energy harvesting nodes. Through data collection of solar-powered nodes and wind-powered coordinator node, the availability of the circuit system is verified. Meanwhile, while the system is running, a series circuit parameters test is finished to provide a reference for further study of energy harvesting wireless sensor network technology.By platform testing in outdoor environment and software debugging based on TI Z-Stack, problems which occur in course of the energy harvesting nodes are analyzed to achieve improvements circuit system. Further solutions are given and experience has accumulated for engineering applications.