The Design Of Wireless Sensor Nodes

WSN (Wireless Sensor Network) is a complex network composed by a large number of distributed wireless sensor network nodes that are often working in inaccessible places. Nodes can acquire and process sensor data, and finally send the data to the monitoring center by wireless sensor networks based on wireless multi-hop routing. Wireless Sensor Network is often used for monitoring ambient temperature, humidity, light intensity, gas concentration.This paper describes the characteristics of the wireless sensor networks and protocols, and design a hardware circuit of the wireless sensor network node based on ATmega128L and NRF905 wireless chip, with Protel99se software designing schematic and PCB, meanwhile programs system program in C language.Nodes realize sensor data acquisition, data processing, wireless communication, serial communication, and the implementation of the MAC protocol based on a simple flooding-based protocols multi-hop routing algorithm. Nodes not only provide radio frequency sleep mechanisms that ensure its low power consumption, but also provide wireless carrier sense mechanisms to ensure reliable transmission of data packets. Finally, we receive packets by serial debugging assistant and form the network topology though analysis the data packets in the experiments. This paper describes the use of ATmega128L node and NRF905 with 10 registers. Because of its simple figuration, no send leading code, lower power consumption and that each node can be a Sink node, it is very convenient to use; at the same time, system program is designed in C language, using flood routing protocols, routing protocols simple. Compared with the operating system TINYOS, it has readability, good portability, short development cycle. The nodes avoid the complexity of the current node circuit design, shorten the time of waking up and lower consumption.