TrailCurrent Seven Pin Trailer Monitor

Firmware module that monitors the state of a 7-pin trailer connection including voltage, turn signals, brakes, and running lights, reporting status over a CAN bus interface.

Overview

• Microcontroller: ESP32-C6
• Function: 7-pin trailer connector monitoring with CAN bus reporting
• Key Features:
  • Monitors trailer voltage, turn signals, brakes, and running lights
  • CAN bus communication at 500 kbps
  • Over-the-air (OTA) firmware updates via WiFi
  • RGB LED status indicator
  • FreeRTOS-based asynchronous monitoring
  • Custom flash partition layout with dual OTA slots

Hardware Requirements

Pin Connections

GPIO	Function
2	Trailer voltage sensing (analog)
3	Left turn/brake line
4	Right turn/brake line
5	Electric brake line
0	Running/tail lights
8	RGB status LED
15	CAN TX
14	CAN RX

Firmware

See src/ directory for PlatformIO-based firmware.

Setup:

# Install PlatformIO (if not already installed)
pip install platformio

# Build firmware
pio run

# Upload to board (serial)
pio run -t upload

# Upload via OTA (after initial flash)
pio run -t upload --upload-port esp32c6-DEVICE_ID

Firmware Dependencies

This firmware depends on the following public libraries:

• C6SuperMiniRgbLedLibrary (v0.0.1) - RGB LED status indicator driver
• Esp32C6OtaUpdateLibrary (v0.0.1) - Over-the-air firmware update functionality
• Esp32C6TwaiTaskBasedLibrary (v0.0.2) - CAN bus communication interface

All dependencies are automatically resolved by PlatformIO during the build process.

WiFi Credentials (for OTA updates):

• Copy src/Secrets.h.example to src/Secrets.h and fill in your WiFi credentials
• Never commit Secrets.h to version control (it's in .gitignore)

Monitoring Data

The TrailerConnection class tracks:

• Trailer connection voltage (analog reading)
• Left turn/brake signal state
• Right turn/brake signal state
• Tail and running light state
• Electric brake percentage

CAN Bus Protocol

• Receive ID 0x00: OTA update notifications - triggers firmware update when device ID matches
• Monitoring runs on FreeRTOS core 0 with callback-based state change notifications

OTA Updates

See docs/OTA.md for detailed over-the-air update documentation including the Python upload script.

Project Structure

├── docs/
│   └── OTA.md                    # OTA update documentation
├── src/
│   ├── Main.cpp                  # Main application
│   ├── Globals.h                 # Debug macros and data structures
│   ├── TrailerConnection.cpp     # Trailer monitoring class
│   ├── TrailerConnection.h       # Trailer monitoring header
│   └── Secrets.h.example         # WiFi credentials template
├── platformio.ini                # Build configuration
└── partitions.csv                # ESP32 flash partition layout

License

MIT License - See LICENSE file for details.

Contributing

Improvements and contributions are welcome! Please submit issues or pull requests.