Road lighting system solutions based on the Internet of Things

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Road lighting system solutions based on the Internet of Things [Copy link]

1 Introduction With the development of urban economy and scale, various types of roads are getting longer and longer, the number of motor vehicles is increasing rapidly, and the traffic volume at night is also increasing. The quality of road lighting directly affects traffic safety and urban development. How to improve the quality of road lighting, reduce energy consumption, and achieve green lighting has become a key issue in urban lighting. The primary task of road lighting is to provide safe and comfortable lighting brightness on the basis of saving public energy, so as to reduce traffic accidents and improve transportation efficiency. Due to the limitations of infrastructure conditions, there is currently a general lack of street light-level communication links. The street light control method can generally only control the entire road in a unified manner, and it is impossible to measure and control each lamp. Based on the Internet of Things, this paper designs an embedded wireless street light control module, which realizes the wireless autonomous networking of each street light, so that each street light can be remotely sensed and remotely controlled, and connected with some units in the street light facilities (such as electronic ballasts, etc.), so that the brightness (or illumination) of the street light can be adjusted from 30% to 100%. Under the conditions of ensuring the quality of road lighting, improving identification reliability and visual comfort, according to the ambient light intensity and time period, 20% to 30% of electricity can be saved. 2 System Structure The structure of the road lighting system based on the Internet of Things is shown in Figure 1. By embedding a wireless communication module in each street lamp, they can form a self-network, receive commands from the control center and feed back the status of the street lamp to the control center. The HG-2 control box uses ZigBee technology to communicate with all street lamps on the roads under its jurisdiction, and uses GPRS to communicate with the control center. According to the instructions of the control center or the time and daylight intensity, it issues control commands to each street lamp (street lamp on, off, illumination (power size), etc.), and automatically adjusts the power balance of the entire road. The control center consists of a server, a large-screen display, and the CenterView central control system software platform. The CenterView central control system software platform adopts a 3D design, and can observe and control the lighting conditions of the entire city, a street, a road, and even a street lamp from a bird's-eye view through zoom transformation. Mobile computing tools (laptops, PDAs, mobile phones) and street lamp maintenance vehicles can also perform remote telemetry and remote control through the control center. [/back color] 3 Wireless communication module [size= 4] 3.1 Module Design MC13213 wireless communication module uses SiP technology to integrate the MC9S08GT main control MCU and MC1320x RF transceiver in a 9×9mm LGA package. MC13213 has 4KB RAM, 60KB FLASH, 1 Serial Peripheral Interface (SPI), 2 Asynchronous Serial Communication Interfaces (SCI), 1 Keyboard Interrupt Module (KBI), 2 Timer/PWM Modules (TPM), 1 8-channel 10-bit Analog/Digital Converter (ADC), and up to 32 GPIO ports, etc. As shown in Figure 2. color] The wireless communication module adopts ZigBee technology and IEEE802.15.4 protocol, the communication coverage radius can reach 150m, and it can self-organize the network and communicate with any street lamp node within its coverage. In addition to realizing the connection of street lamps, it also has the functions of adjusting the power output of electronic ballasts (30%~100%) to achieve energy saving and green lighting, detecting the current, voltage, power factor of the power supply line and the working status of each lamp, and when a fault occurs (such as lamp damage, lamp pole collision, human damage), it will send an alarm to the monitoring center and relevant departments in real time. The wireless communication module is also designed to be rainproof, moisture-proof, lightning-proof, and electromagnetic interference-proof, and fully considers easy installation, simple maintenance, and recoverability (connecting two wires can achieve street lamp-level wireless control, and removing the two wires can restore to the original state). It can be embedded in different positions of street lamps (at the bottom of the lamp pole, inside the lamp pole, and inside the lampshade). 3.2 Communication Protocol The communication protocol of the wireless communication module is as follows: the lighting is numbered in sequence according to the road sections, and the “hand-in-hand” communication between nodes is achieved through command forwarding and status return. Command forwarding mechanism: Each node uses a bitmap structure to record which frames have been forwarded (the bitmap can represent up to 256 frames). If a node receives a command frame, it determines whether the frame has been forwarded by the node. If so, the frame is discarded (the node only forwards the received command frame and does not modify the content of the frame), thereby ensuring that a line is controlled at the fastest speed and effectively preventing a node failure from affecting the operation of the entire line; Status return mechanism: After the command frame is sent to the designated node, the designated node receives the command and immediately returns the status; Forwarding rules: Only when the node number is smaller than the target node number will it be forwarded, and the status return process is the opposite. A transmission communication link is composed of several ZigBee nodes. A cluster node is set among these nodes (one road can have one or more cluster nodes). Its function is to communicate with the control center in GPRS mode (command acceptance and status return). The cluster node uses CodeFire series MCF52223 chip as the control unit, and GTM900B and EM770W as long-distance wireless communication modules. The MCF5222x series is built using the commonly used V2ColdFire core and has a performance of up to 76MIPS (Dhrystone2.1), interface functions include: 1 MiniUSB interface, support USBOTG function, 3 2-wire serial ports, 1 microphone input interface, 1 HEADSET input/output interface, 1 HANDSET input/output interface, 1 8Ω/16Ω speaker output interface, 1 132*96 dot matrix LED, 1 5*5 key keyboard, support RTC, ADC, PIT＆GPT, PWM, etc.; GTM900B and EM770W complete long-distance GPRS communication. 4 Control center software design The software design platform of the control center is Windows 2003, the development tool is Microsoft Visual Studio 2005, and the database uses SQL Server 2005. After obtaining the location, shape and other characteristic information of streets, buildings and street lamps, a 3D virtual city with street lamps as the main body is designed. The lighting effect of the road is dynamically displayed on the large screen of the control center, and the lighting conditions of the entire city, streets and even each street lamp can be observed through geometric transformations such as translation, zooming in and out. The software mainly has 5 functional modules: system settings, intelligent control, power accounting, fault handling and emergency plans. There are 4 types of regional settings in the system settings, including city, district, street and electric control box; the street light settings include the location, model, production unit, construction unit, maintenance person, installation date, cleaning and maintenance date, etc. of the street light; the lighting mode settings include full on, full off, odd-numbered street lights on, odd-numbered street lights off, even-numbered street lights on, even-numbered street lights off, 1/3 street lights on, 1/3 street lights off, 1/4 street lights on, 1/4 street lights off, and intelligent control, etc. There are 11 control modes, including the time period setting, which can set the lighting mode for different time periods according to different seasons in different cities; intelligent control has two aspects: for sections where electronic street lights are installed, the lighting brightness of the street lights is intelligently adjusted by real-time sampling of ambient light intensity according to seasonal changes and weather conditions; at night, especially late at night When it is detected that the traffic of cars and pedestrians is very scarce, the road lighting brightness is appropriately reduced without affecting the reliability of identification to save power consumption; power accounting can count and calculate the power consumption of cities, districts, streets, electric control boxes and even each street lamp; fault handling is to quickly generate a fault report after reporting to the monitoring center in the first time for situations such as lamp damage, power failure, phase failure, overcurrent, overvoltage, three-phase imbalance and human damage; another function of fault handling is to count the lighting rate, fault rate, and efficiency of each fault handling (average repair time) by road section and time period (year, quarter, month); emergency plans are formulated for some emergencies. In special circumstances, appropriate road lighting is provided as much as possible to ensure the safety of people's lives and property. Figure 3 is one of the operating interfaces of the control center software. 6 Conclusion Advanced road lighting can not only enhance the image of the city, improve transportation efficiency, reduce traffic accidents, but also save a lot of public electricity consumption. However, for most cities, due to the lack of necessary infrastructure (street lamp-level communication links), advanced control methods cannot be implemented. The emergence and application of the Internet of Things (IoT) effectively solves the above problems.

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