3.6 KiB
3.6 KiB
Matter over Thread Architecture
This document outlines the architectural decision and technical implementation strategy for integrating external end devices (e.g., display-less components like lighthouses, signals) into the System Control ecosystem.
1. Architectural Decision: Why Matter over Thread?
We have decided to use Matter over Thread as the standard communication protocol between the main controller (ESP) and external end devices.
Key Benefits
- Standardization: Matter provides a standardized application layer (Clusters and Endpoints). A "light" or "blinking" function is mapped to standard clusters (e.g.,
OnOff Cluster), meaning the UI and backend do not need custom JSON parsing for every new device type. - Ecosystem Compatibility (Multi-Admin): Matter's Multi-Admin feature allows a single end device to be controlled by multiple controllers simultaneously. This means a device can be paired to the ESP's web UI and directly to Apple Home or Google Home at the same time.
- Robust Infrastructure: Thread provides a self-healing IPv6 mesh network. The ESP acts as the Thread Border Router and Matter Commissioner.
2. System Roles
Main Controller (ESP)
- Thread Border Router / Commissioner: The ESP creates and manages the Thread network. It exposes a "Permit Join" window (accessible via the Web UI) to allow new, display-less devices to join the network.
- Matter Controller: The ESP acts as a Matter Controller. Once a device is on the Thread network, the ESP discovers its capabilities (Clusters) and exposes them to the Web UI for configuration and control.
End Devices (e.g., Lighthouse)
- Act as standard Matter Accessories.
- Join the Thread network during the "Permit Join" window using their setup code (PSKd).
- Expose their capabilities as standard Matter endpoints (e.g., Endpoint 1: Light, Endpoint 2: Blinking feature).
3. UI Workflow
The web interface separates network infrastructure from application control:
- System Tab (Infrastructure): Used to open the Thread network ("Pair Devices" / Permit Join) so that new devices can receive an IP address and join the mesh.
- Configuration Tab -> Devices (Discovery): Used to discover Matter devices that have joined the network, authenticate them via their Setup PIN, and map them to the system database.
- Control Tab (Application): Dynamically displays controls (buttons, toggles) based on the discovered Matter clusters of the paired devices.
4. Development and Certification Notes (DIY / Hobby)
For private, DIY, and development purposes, no official CSA (Connectivity Standards Alliance) certification is required.
We utilize Test Vendor IDs (VID) (e.g., 0xFFF1) and Test Product IDs (PID).
Ecosystem Behavior with Test Certificates
- Apple Home (iOS): Apple allows pairing of uncertified Matter accessories. During the pairing process, iOS will display a warning ("This accessory is uncertified"). The user can simply click "Add anyway" to bypass this and use the device normally.
- Google Home: Google requires explicit permission to add uncertified devices. Developers must log into the free Google Home Developer Console and register their Test VID and PID. Once registered, the Google Home app on the developer's smartphone will allow pairing without errors.
- Our ESP Controller: The ESP Matter SDK will be configured to accept test certificates during the Attestation phase (PASE/CASE), ensuring seamless pairing without warnings.
Documented to ensure a shared understanding of the IoT communication strategy within the project team.