Design a Low-Cost IoT Gateway Using for the Smart Traffic Light Control System in Vietnam

This paper presents the design and implementation of a low-cost IoT gateway for smart traffic light control systems in Vietnam. The proposed gateway utilizes the LoRa RA-02 SX1278 (433 MHz) module for long-range communication with IoT nodes and the ESP8266 WiFi module for cloud connectivity. The firmware for both the gateway and the nodes was developed in C/C++, supporting real-time bidirectional data exchange using JSON over HTTPS. A prototype system was built and successfully tested, demonstrating stable control of electrical devices on LoRa in urban environments up to 1.5 km. The system was deployed in a smart traffic project that integrates image processing to dynamically manage traffic lights based on vehicle density. The results confirm the feasibility of a scalable and cost-effective IoT infrastructure for smart city applications in developing countries.