Extending a 25-year-old Volvo with a network of micro-controllers.
(Yes, your car can get smarter — and maybe rebel gently.)

✅ Completed Features

• Master Controller: ESP32-based coordinator with WiFi AP, REST API, and MQTT broker
• MQTT Integration: Full pub/sub messaging system for real-time control events
• Abstract Member Controller: Base class with WiFi client, REST registration, and MQTT client
• Error Handling: Comprehensive system (100-999) with severity levels
• Logging System: 5-level logging (DEBUG, INFO, WARN, ERROR, CRITICAL) with timestamps
• Version Tracking: Firmware versioning with build metadata and feature flags
• Health Monitoring: System status endpoint with memory and device statistics
• Connection Management: Retry logic with exponential back-off
• Control ID Allocation: Documented ID ranges to prevent conflicts
• Documentation: Guides for member controllers & MQTT usage

🔧 In Progress

• Hardware controller implementations (HID, Relay Bank, Sensor Bank)
• Configuration management system (web UI + SPIFFS storage)

🎯 Planned Features

• Specialized controllers (GPS, Camera, Display, OBD-II)
• OTA firmware updates
• Advanced MQTT (QoS 1, retained messages)
• Web-based configuration interface
• Data logging & analytics

• REST API: Device registration, configuration & status queries
• MQTT: Real-time control events, sensor data, inter-device messaging

• Master Controller: Central coordinator — WiFi, REST, MQTT broker
• Member Controllers: Specialized devices for functions like:
  • Human Interface (HID) → switches/buttons
  • Relay Bank → lights/accessories
  • Sensor Bank → temperature/motion/light sensors
  • GPS Interface, Camera, Display, OBD-II Diagnostics … and more

1. cd Melvin_master_controller/
2. Read GETTING_STARTED.md for configuration
3. Build with PlatformIO: pio run
4. Flash to ESP32: pio run --target upload
5. Monitor output: pio device monitor

1. cd Melvin_member_controllers/Mcontrol_Abstract/
2. Read README.md & CUSTOMIZATION_GUIDE.md
3. Copy template to create a custom controller
4. Set device ID and control IDs
5. Build and flash to ESP32

Melvin/
├── .gitignore
├── README.md
├── LICENSE
├── Melvin_controller_scheme.md
├── CONTROL_ID_ALLOCATION.md
├── Melvin_master_controller/
│   ├── include/
│   ├── src/
│   ├── platformio.ini
│   ├── README.md
│   ├── GETTING_STARTED.md
│   └── ...
└── Melvin_member_controllers/
├── README.md
├── Mcontrol_Abstract/
├── Mcontrol_HID/
├── Mcontrol_Relay_Bank/
└── ...

• ESP32 or ESP32-S3 development board
• 12 V automotive power supply (with 3.3 V regulation)
• Additional electronics: sensors, switches, relays per use-case
• USB cable for programming/debugging

This is automotive electronics territory:

• Use proper fuses and circuit protection
• Test thoroughly before integrating
• Never compromise critical vehicle systems
• If unsure, consult a professional

This is a personal project, but feel free to reuse ideas and code. All code is provided as-is under the MIT license. PRs welcome though, I would love to see what you're working on, or how you're using Melvins distributed modules to reduce the need for long wire runs.

• Melvin_controller_scheme.md: Architecture and API overview
• CONTROL_ID_ALLOCATION.md: Control ID assignment guide
• Master & Member controller docs located in their respective directories