Android Smart Glasses (ASG) Client Architecture

Overview

The ASG Client is an Android application that runs on smart glasses, acting as the bridge between hardware capabilities and the MentraOS ecosystem.

System Architecture

┌─────────────────────────────────────────────────────────┐
│                    Smart Glasses Hardware                │
│  ┌─────────────┐  ┌──────────────┐  ┌───────────────┐  │
│  │   Camera    │  │     MCU      │  │   Bluetooth   │  │
│  │             │  │  (Buttons)   │  │     Chip      │  │
│  └──────┬──────┘  └──────┬───────┘  └───────┬───────┘  │
│         │                │                   │           │
└─────────┼────────────────┼───────────────────┼───────────┘
          │                │                   │
          ▼                ▼                   ▼
┌─────────────────────────────────────────────────────────┐
│                    ASG Client Service                    │
│  ┌─────────────┐  ┌──────────────┐  ┌───────────────┐  │
│  │   Camera    │  │   Command    │  │   Bluetooth   │  │
│  │   Manager   │  │   Parser     │  │   Manager     │  │
│  └──────┬──────┘  └──────┬───────┘  └───────┬───────┘  │
│         │                │                   │           │
│         └────────────────┴───────────────────┘           │
│                          │                               │
│                    ┌─────▼──────┐                        │
│                    │ AsgClient  │                        │
│                    │  Service   │                        │
│                    └─────┬──────┘                        │
└─────────────────────────┼───────────────────────────────┘
                          │
                          ▼ BLE
                    ┌───────────┐
                    │  Mobile   │
                    │    App    │
                    └─────┬─────┘
                          │
                          ▼ Internet
                    ┌───────────┐
                    │ MentraOS  │
                    │   Cloud   │
                    └───────────┘

Core Components

AsgClientService

The main Android service that coordinates all functionality:

public class AsgClientService extends Service {
    // Core managers
    private IBluetoothManager bluetoothManager;
    private INetworkManager networkManager;
    private MediaCaptureService mediaCaptureService;

    // Message processing
    private void processReceivedMessage(String message);
    private void parseK900Command(String command);

    // Hardware integration
    private void handleButtonPress(boolean isLongPress);
    private void sendBatteryStatus();
}

Manager Pattern

The client uses interface-based managers for device abstraction:

// Network Manager Interface
public interface INetworkManager {
    void setWifiEnabled(boolean enabled);
    void connectToWifi(String ssid, String password);
    boolean isConnectedToWifi();
    String getCurrentWifiSsid();
}

// Bluetooth Manager Interface
public interface IBluetoothManager {
    void initialize();
    void sendData(byte[] data);
    boolean isConnected();
    void setConnectionListener(ConnectionListener listener);
}

Factory Pattern

Managers are created via factories based on device type:

public class NetworkManagerFactory {
    public static INetworkManager create(Context context) {
        if (isK900Device()) {
            return new K900NetworkManager(context);
        } else if (hasSystemPermissions()) {
            return new SystemNetworkManager(context);
        } else {
            return new FallbackNetworkManager(context);
        }
    }
}

Message Flow

Incoming Messages (Phone → Glasses)

BLE Reception: BluetoothManager receives data
Parse & Route: AsgClientService processes JSON
Execute Command: Appropriate manager handles action
Send Response: Status sent back via BLE

Outgoing Messages (Glasses → Phone)

Event Occurs: Button press, status change, etc.
Format Message: Create JSON message
Send via BLE: BluetoothManager transmits
Phone Relay: Mobile app forwards to cloud

Command Processing

MCU Commands

Commands from the microcontroller (hardware events):

// Button press commands
"cs_pho" → Short camera button press (photo)
"cs_vdo" → Long camera button press (video)

// Other hardware commands
"hm_batv" → Battery status update
"cs_swst" → Swipe gesture

Cloud Commands

Commands from MentraOS Cloud (via phone):

{
  "type": "take_photo",
  "requestId": "uuid-1234"
}

{
  "type": "start_stream",
  "streamUrl": "srt://server:4201?streamid=key",
  "streamId": "uuid-5678"
}

Service Lifecycle

Service Start
- Initialize managers
- Setup BLE advertising/connection
- Start monitoring hardware
Runtime Operation
- Process incoming messages
- Handle hardware events
- Manage network state
- Upload queued media
Service Stop
- Clean up resources
- Stop active streams
- Save state for restart

Threading Model

Main Thread: UI operations, service lifecycle
BLE Thread: Bluetooth communication
Network Thread: WiFi operations, uploads
Camera Thread: Media capture operations

State Management

The service maintains state for:

Connection status (BLE, WiFi)
Active operations (streaming, recording)
Hardware state (battery, temperature)
Configuration (button modes, settings)

Error Handling

Graceful Degradation: Fallback behaviors for failures
Retry Logic: Automatic retry for network operations
State Recovery: Restore after service restart
User Feedback: Status messages via BLE

​Android Smart Glasses (ASG) Client Architecture

​Overview

​System Architecture

​Core Components

​AsgClientService

​Manager Pattern

​Factory Pattern

​Message Flow

​Incoming Messages (Phone → Glasses)

​Outgoing Messages (Glasses → Phone)

​Command Processing

​MCU Commands

​Cloud Commands

​Service Lifecycle

​Threading Model

​State Management

​Error Handling