Design And Implementation Of A Low-power Temperature And Humidity Wireless Sensor Network

At present, the temperature and humidity monitoring system plays an important role in industrial and agricultural production, and also in people’s daily lives. There are a wide variety of monitoring systems, basically can be divided into two kinds according to the way of transmission, cable transmission and wireless transmission. As wireless sensor networks (WSN) technology is more mature, use wireless sensor networks to achieve temperature and humidity monitoring at the sence has advantages of simple circuits, low power consumption, low cost, and portability.In wireless sensor networks, sensor nodes mostly are powered by batteries, its power consumption becomes the current urgent problems to be solved. This paper focus on the shortcomings of the current temperature and humidity sensor networks designed and implemented a low-power, low-cost, good performance and stability of a temperature and humidity wireless sensor network.In this paper, a low-power WSN based on RF technology is designed to achieve environmental temperature and humidity monitoring. For the low-power needs of sensor nodes, this system uses MCF51QE128microcontroller, nRF905wireless RF module, and SHT11digital temperature and humidity acquisition module to form sensor nodes, and use MCF51QE128’s specific low power features, and work-sleep low-power mechanism to achieve temperature and humidity acquisition and data transmission. The system applys MCF52235microcontroller and nRF905wireless RF module to form a sink node, and completes temperature and humidity data collection and real-time display on the LCD. When use more than one node to form a network, the system uses a star topology, and different time division to achieve multiple accesses and complete the communication between the sink node and sensor nodes at the scene. And though RTS/CTS handshaking protocol, this system realizes the network access of new sensor node, and the distribution of transmission time slots. This system also designed a C#API on host computer, to acheieve real-time monitoring and recording the changes of temperature and humidity.The results show that the system meets the basic needs of real-time monitoring of temperature and humidity at the sence in this wireless sensor network, it can reach200meters distance of communication, power consumption is3.616mW. This system has a good scalability, and a good application value.