At present, the widely used wired connected street lighting systems generally have high construction costs and complex routes, which are difficult to expand and control, and therefore cannot meet the lighting needs of highways in harsh weather environments. How to ensure the intelligent opening, adjustment, and stable operation of the street lighting system on highways in harsh weather conditions such as heavy fog without human intervention has become a technical challenge. This article adopts ZigBee technology and LED drive control technology to attempt to design an intelligent street light control system for anti fog on highways. The terminal node module of the system can collect real-time data from relevant sensors and transmit it to the coordinator module. The coordinator module then sends the collected data to the Internet of Things cloud platform through GPRS network, and then manages and controls it in real time through connected intelligent terminal devices (such as PCs or mobile phones). Considering that many highways do not have street lights installed, the street lighting system in this article can adopt solar panels and batteries as a safe and reliable power supply.
Due to the superior energy consumption, luminous efficiency, lifespan, and low voltage drive of LED street lights compared to traditional street lights [1-3], this street light system considers adopting LED street lights to provide lighting.
ZigBee is a set of IEEE based 802.15.4 wireless standards, which are technical standards related to networking, security, and application software. It has advantages such as short distance, low complexity, low energy consumption, low speed, and low cost, making it suitable for application in lighting systems [4].
Based on ZigBee's wireless communication technology, the distance between network nodes can range from 75 meters to several hundred meters, with a maximum length of several kilometers. In addition, ZigBee network can achieve interconnection and interoperability with various existing network platforms, making it possible to connect and work together with IoT cloud platforms. At present, applications based on ZigBee have penetrated into various fields such as healthcare, home furnishings, transportation, and indoor positioning [5-8].
How does the system determine visibility and intelligently turn on street lights on highways in harsh weather conditions such as heavy fog? Related studies have shown that PM2.5 and relative humidity have the greatest impact on visibility [9-11].
Dong Ruxin and Zhang Qingshuang (2014) experimentally investigated the correlation between visibility and PM2.5 and PM10 in different RH ranges; The correlation between atmospheric visibility and PM2.5, PM10, and relative humidity RH follows the pattern of RH>PM2.5>PM10 [10].
Chen Xiaochuan (2017) used PM2.5, PM10 concentrations, and relative humidity data to quantitatively invert and calculate visibility, and applied it to the highway fog monitoring system: in foggy or hazy weather conditions, through the analysis of visibility and meteorological parameters, if the alarm value is exceeded, the alarm light will be lit and an alarm message will be sent to the traffic speed limit control system to remind drivers to pay attention; And promptly notify relevant regulatory departments and traffic police, and take necessary and effective measures to ensure smooth and safe road traffic.
Chen Xiaochuan (2017) used PM2.5, PM10 concentrations, and relative humidity data to quantitatively invert and calculate visibility, and applied it to the highway fog monitoring system: in foggy or hazy weather conditions, through the analysis of visibility and meteorological parameters, if the alarm value is exceeded, the alarm light will be lit and an alarm message will be sent to the traffic speed limit control system to remind drivers to pay attention; And promptly notify relevant regulatory departments and traffic police, and take necessary and effective measures to ensure smooth and safe road traffic.
This article focuses on using sensors (including temperature and humidity sensors, PM2.5, PM10 particle concentration sensors) to monitor environmental meteorological data in real-time, in order to determine weather visibility on highways.