Research On Wireless Sensor Network Node Based On ATmega128

In this paper, according to reading and analyzing the development at home and abroad of the wireless sensor network and combining with actual research conditions, a kind of wireless sensor node is designed which is suit for industrial field data collection and mobile object positioning. Node processor uses ATmega128 microcontroller, wireless communication chip selects CC2420 that is compatible with 2.4GHz IEEE 802.15.4. After debugging, sensor node can accomplish the sensor's data collection, at the same time, it can sent the collected data to a terminal node and achieve data communication between the two nodes. Sensor nodes as well as can display the collected data in the PC through connecting RS232 with it.The paper also designed an ultrasonic sensor module used for mobile node location. Sensor nodes targeting mechanism is based on the distance, ultrasound and received signal strength are the two ways to ranging in the experiment, and then using MATLAB for the analysis and processing of the experimental data. The ultrasonic ranging used in the paper is based on Time Difference of Arrival (TDOA), differs from the previous approach of basing on time of arrival (TOA), there is no synchronization requirements between the nodes. Experiments show that the ranging method based on signal reception strength receives a larger error and the ranging method based on ultrasound receives a less error, so the position located method based on ultrasound has a higher accuracy. In order to facilitate the monitoring and management of sensor nodes, a management system is developed using VC++ in the PC. The system has the functions of data storage, position calculation and data mapping, achieves the visual management for the sensor nodes.