ZigBee intelligent control system design for LED street light control

Streetlights are an indispensable lighting tool in the daily life of residents. With the rapid development of economy and urbanization, people have made improvements and optimizations to the streetlight system. Traditional streetlight lighting systems are generally wired, with high system construction costs, complicated lines, difficulty in expansion and movement, and low intelligence. In order to improve the many inconveniences of traditional streetlights, people combine new technologies with streetlight systems and use wireless control instead of wired control to make streetlights smarter and more convenient. ZigBee technology is a new type of wireless communication technology, which is mainly used for information transmission within a short distance. It has many advantages. Combining this technology with streetlight lighting systems is a favorable innovation. In addition, in order to respond to the needs of modern sustainable development, we use LED  streetlights for lighting from the perspective of energy conservation and emission reduction. This ZigBee-based streetlight intelligent control system has the advantages of stability, safety, convenience and efficiency.

　　1. ZigBee networking technology

　　The advantages of ZigBee technology are low power consumption, low technical cost, simple structure and large capacity. The network topology is divided into two types: mesh topology and tree topology, and the tree topology is commonly used. The entire network mainly includes three types of devices, including network coordinator, full function device (FFD) and reduced function device (RFD).

　　2. Composition of street light control system

　　The intelligent control system of street lamps consists of the following three components:

　　(1) Microprocessor control system. It consists of routing nodes and leaf nodes. Its main structural components include street light dimming controller, DC power supply system, communication control system and light intensity sensor;

　　(2) The server monitoring system of the control center. It consists of a coordinator and a PC;

　　(3) Intelligent control system: It is a ZigBee wireless network used to control the operation of the entire system.

　　The control system structure of the microprocessor is generally a multi-way tree network topology structure. The monitoring system of the control center, several routing nodes and several RFD nodes constitute the network coordinator of the entire system. In each part, the routing nodes are installed next to the road in a serial connection. After that, the router is used as a relay controller to remotely control the street lights. At the same time, it also has the function of controlling LED lights as an independent user node. The RFD user node does not have the function of a routing node and cannot be used as a repeater. It can only receive signals and control its own LED lights according to the received signals.

　　3. System software design

　　The design of system software mainly includes four parts, namely PC server background software design, coordinator software design, router software design and leaf node software design.

　　3.1 PC server background software design

　　When the PC controls the entire system, the command is sent to the coordinator through the serial port, and then the control is completed through the human-machine interface. During work, the main function of the PC server is to send control commands to the coordinator, which will command the coordinated action to control. The coordinator reads the data information obtained from the ZigBee network and returns this data to the PC server. Then the PC will save the operating data and system parameters during work.

　　3.2 Coordinator Software Design

　　After the coordinator is initialized, the first step is to establish a carrier waiting for nodes to join. This carrier is an intelligent network. Each node that is found to apply to join the network will be assigned a network number. In the monitoring function of the coordinator, the coordinator will control a certain node according to the corresponding instructions of the PC, such as the control of the node light, the control of the node time period, etc. At the same time, the coordinator also plays a role in data exchange. If the command is to make a certain node read relevant information, it will send the read data information to the PC server through the serial port.

　　3.3 Router Software Design

　　The first step of the router's electrical initialization is to apply to the coordinator to join the coordinator network. If you fail to join the network the first time, you need to keep applying to the network, otherwise the system network will not be able to control the node. Once you successfully join the network, the routing node will be in a monitoring state. Its monitoring work is divided into three aspects. The first point is the monitoring of other nodes. It will automatically assign network addresses to routing nodes or leaf nodes that apply to join the network; the second point is the monitoring of commands sent from the coordinator. When it receives a command, it will adjust the parameter settings of each part according to the content of the command. If the coordinator sends a status read command, it will send the working status of the node to it according to the instructions. Therefore, different commands have different indicative effects on the router; the last point is the control of the preset value. This part of the monitoring is made by the router after collecting the ambient brightness information. Since the brightness is different in each period of time, the switch and operation of the street light will also make intelligent changes according to the analysis of the router.

　　3.4 Leaf Node Software Design

　　The process of leaf node is similar to that of routing node, but slightly different. Because leaf node is a terminal node, it does not support other nodes to join.

　　4. Conclusion

For this LED street light intelligent control system 　　using ZigBee technology   , its benefit is that it solves the problem of low energy utilization of the street light system. The application of LED street lights can greatly reduce energy consumption and improve the economic benefits of the system. The system is highly safe, stable and reliable, and it has abandoned the intricate line structure, which is more convenient and reduces the space volume. High-power LED street lights provide a new development direction for people's lighting . By combining other new sensors and controllers, remote street light wireless control technology is realized, which effectively achieves intelligent application and has a wide range of applications, effectively improving the utilization of energy. At the same time, we can infer that this new street light control method will have broad development prospects in the future. With the development of the economy and the progress of society, people's future lives will move towards a more intelligent and comfortable direction.