--- title: "stm32f103_w5500" url: "https://maker.wiznet.io/mason/projects/stm32f103-w5500-1/" markdown_url: "https://maker.wiznet.io/mason/projects/stm32f103-w5500-1/md" type: "UCC: User Created Content" author: "amidg" author_url: "https://github.com/narudoltatiyavattanachai/stm32f103_w5500" editor: "WIZnet" editor_url: "https://maker.wiznet.io/" original_author: "amidg" original_url: "https://github.com/narudoltatiyavattanachai/stm32f103_w5500" license: "MIT license (MIT)" published: "2025-12-03" language: "en" tags: ["STM32", "W5500"] hardware: ["STMicroelectronics STM32F103RCT6", "WIZnet W5500"] likes: 0 views: 2472 comments: 0 source: "WIZnet Makers (https://maker.wiznet.io/)" --- # stm32f103_w5500 > Smart Traffic Edge Node with STM32F103 & W5500 Original author: amidg (source: https://github.com/narudoltatiyavattanachai/stm32f103_w5500) ## Components - **STMicroelectronics STM32F103RCT6** x 1 ([docs](https://estore.st.com/en/stm32f103rct6-cpn.html)) - **WIZnet W5500** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500)) WIZnet parts: W5500 ([Datasheet](https://docs.wiznet.io/Product/Chip/Ethernet/W5500/datasheet?utm_source=maker&utm_medium=project&utm_campaign=w5500), [product hub](https://maker.wiznet.io/products/w5500/)) ## Documents and links - [Github Code](https://github.com/narudoltatiyavattanachai/stm32f103_w5500) (code) ## Article ## Project Goal – Edge Computing for Smart Traffic **Real-time traffic monitoring and control** Quickly collect data from traffic lights, intersections, and crosswalks, and perform control actions locally at the edge. **Minimizing latency through local processing** Instead of sending all data to the cloud, the edge MCU makes the first decision and forwards only the necessary information to the upper-level system. **Seamless integration with smart city infrastructure** Using micro-ROS, the node can easily integrate with ROS 2–based central traffic management systems and cloud analytics platforms. Original link: [https://github.com/narudoltatiyavattanachai/stm32f103_w5500](https://github.com/narudoltatiyavattanachai/stm32f103_w5500?utm_source=chatgpt.com) --- ## Hardware Configuration – STM32F103C8T6 + W5500 Ethernet This project uses the following hardware combination: ### MCU STM32F103C8T6 (72 MHz, Cortex-M3) ### Network WIZnet W5500 Ethernet controller: Built-in hardware TCP/IP stack to offload networking from the MCU ### Other Characteristics I/O layout designed with external sensors in mind (vehicle detection, pedestrian detection, etc.) ![Demo_Board.png](https://github.com/narudoltatiyavattanachai/stm32f103_w5500/blob/main/docs/pics/Demo_Board.png?raw=true) Image source : --- ## Software Stack – FreeRTOS + micro-ROS + W5500 ### FreeRTOS Task-based real-time operation Separate tasks for sensor reading, communication, and control logic ### micro-ROS Framework that lets resource-constrained MCUs participate in a ROS 2 environment Communicates with the ROS 2 agent through a custom W5500 transport layer ### Network Stack Supports both static IP and DHCP Communication over TCP/UDP protocols Designed with **secure communication channels** in mind (can be extended with TLS in the future) ### Safety Features Watchdog Fail-safe mechanisms aimed at automatic recovery from abnormal states --- ## System Architecture – Role Split Between Central Control and Edge Nodes > Central traffic management system → Edge router → Local network → Smart traffic node > > ![](https://maker.wiznet.io/upload/ckeditor5/1066383715%5F1764863762%2Epng) ### Central Traffic Management (Cloud / Server) Collects and analyzes traffic data from the entire city Sends high-level policy and strategy commands ### Edge Router & Local Network Network that connects multiple edge nodes installed at sites such as intersections and road segments ### Smart Traffic Node (this project) Collects sensor inputs (vehicles, pedestrians, etc.) Performs local decision-making on STM32F103 + FreeRTOS + micro-ROS Exchanges ROS 2 messages with the central system via the W5500 Ethernet interface This architecture fits well with smart city designs that treat **the cloud as the “brain” and the edge as the “reflex” system**. --- ## Project Structure – STM32Cube-Based Design The GitHub repository follows the STM32CubeIDE project structure, so you can import it directly into the IDE and build it without additional setup. ![](https://maker.wiznet.io/upload/ckeditor5/1066383715%5F1764863684%2Epng) Image source : --- ## micro-ROS & ROS 2 Integration The most notable feature of this project is that it **communicates directly with a ROS 2 environment via micro-ROS**. ### Prepare a ROS 2 Environment on the Host PC Install Ubuntu + ROS 2 (Humble, Foxy, etc.) ### Example: Running the micro-ROS Agent `ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888` ### STM32 Edge Node Operation When the board boots, it automatically connects to the micro-ROS agent using the configured IP and port. After that, it can integrate with the ROS 2 ecosystem through topic publish/subscribe, service calls, and more. Through this, the node can: Publish sensor data (traffic volume, pedestrian detection, event information) to ROS 2 topics Receive traffic signal control commands from the central system --- ## Why Use ROS 2 for a Smart Traffic System? ### Treating the Smart Traffic Infrastructure as One ROS System Both the central server (cloud) and intersection edge nodes are treated as ROS 2 nodes, making it easy to connect them via topics and services. ### Easy Implementation of Real-Time and Reliable Communication DDS-based QoS settings (reliability, latency, history, etc.) allow safety-critical messages and logging data to be transmitted according to their requirements. ### Bringing MCUs into the ROS 2 Network With micro-ROS + FreeRTOS, small MCUs like the STM32F103 can participate directly in the ROS 2 graph. ### Leveraging ROS 2 Scalability and Ecosystem Can fully use ros2 tools, simulations, data logging, and integration with other robots or autonomous driving systems without reinventing the wheel. --- Source: https://maker.wiznet.io/mason/projects/stm32f103-w5500-1/