ESP32 Advertiser

This project includes the ESP32 firmware (adv_esp) and a PC-side Python control package (lps-ctrl).

The system sends commands from a PC via UART to the ESP32. The ESP32 transmits these commands to the receivers (LPS, Light Playback System) via BLE Advertising, and collects status feedback via BLE Scanning.

System Architecture

Communication Flow Diagram

graph TD
    PC["Host PC (Python)"] <-->|"UART (Command / Report)"| ESP32["ESP32 Advertiser"]
    
    %% TCP/WiFi OTA Update Path (修正這裡的箭頭)
    PC -.->|"Wi-Fi / TCP (OTA File Transfer)"| LPS1
    PC -.->|"Wi-Fi / TCP (OTA File Transfer)"| LPSn

    %% BLE Control Path
    ESP32 -->|"BLE Advertising (Burst)"| LPS1["LPS Device 1"]
    ESP32 -->|"BLE Advertising (Burst)"| LPS2["LPS Device 2"]
    ESP32 -->|"BLE Advertising (Burst)"| LPSn["LPS Device n"]
    
    %% Feedback Loop
    LPS1 -.->|"BLE ACK (Status)"| ESP32
    LPS2 -.->|"BLE ACK (Status)"| ESP32
    LPSn -.->|"BLE ACK (Status)"| ESP32

Loading

1. PC Control Layer (lps-ctrl)

• Encapsulates commands into a CSV format containing the "Expected Arrival Time (Delay)."
• Non-blocking Control: Implements an asynchronous architecture to trigger status checks without blocking the main command stream.
• Parses streaming status reports (FOUND:...) returned by the ESP32.

2. Hardware Bridge Layer (adv_esp)

• Receives PC commands via UART (baud rate: 115200).
• Hybrid Role: Acts primarily as a Broadcaster, but switches to Observer (Scanner) Mode when a CHECK command is issued.
• Utilizes Raw HCI to bypass the standard Bluetooth stack for precise timing control.

3. Wireless Broadcasting Layer (BLE Interface)

• Burst Mechanism: Continuously transmits synchronization packets before the target time arrives.
• LPS Receiver: Syncs time upon receiving any single packet.
• Status Feedback: Receivers respond with an ACK packet containing their current state and remaining delay when queried, allowing the PC to monitor fleet status.

4. Content Update Layer (TCP/Wi-Fi)

• TCP Server: The PC runs an asynchronous TCP server (Esp32TcpServer) to host content files.
• Mode Switching: Upon receiving the UPLOAD command via BLE, LPS Receivers automatically disable their BLE hardware and enable Wi-Fi to establish a direct connection with the PC.
• Direct Update: Receivers download specific Control (control.dat) and Frame (frame.dat) data files based on their Player ID, save them to the SD card, and automatically reboot to apply the new shows.

Project Structure

├── adv_esp/                # ESP32 BLE Advertiser
│   ├── CMakeLists.txt      
│   └── main/
│       ├── CMakeLists.txt  
│       ├── main.c          # UART handling, command parsing, task scheduling
│       ├── bt_sender.c     # BLE HCI control (TX & RX), packet assembly
│       └── bt_sender.h     
├── lps-ctrl/               # Python control package
│   ├── examples/           # Usage examples (e.g., lps_ctrl_ex.py, tcp_example.py)
│   ├── src/lps_ctrl/       # Core source code
│   │   ├── lps_ctrl.py     # UART Control Logic (ESP32BTSender)
│   │   └── tcp_sender.py   # TCP File Server Logic (Esp32TcpServer)
│   ├── pyproject.toml      # Configuration file
│   └── README.md