> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mentraglass.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Hardware & Capabilities Overview

> Detect and adapt to different smart glasses hardware

**Check what hardware is available using `session.capabilities`.** Different glasses have different features—displays, cameras, speakers, buttons, LEDs. Your app can detect and adapt to each device.

## Accessing Capabilities

```typescript theme={null}
protected async onSession(session: AppSession, sessionId: string, userId: string) {
  const caps = session.capabilities;

  if (!caps) {
    session.logger.warn('Capabilities not loaded');
    return;
  }

  session.logger.info('Device:', caps.modelName);
  session.logger.info('Has camera:', caps.hasCamera);
  session.logger.info('Has display:', caps.hasDisplay);
}
```

## Available Capabilities

| Capability     | Description                | Check With           |
| -------------- | -------------------------- | -------------------- |
| **Display**    | Screen for showing content | `caps.hasDisplay`    |
| **Camera**     | Photo/video capture        | `caps.hasCamera`     |
| **Microphone** | Audio input                | `caps.hasMicrophone` |
| **Speaker**    | Audio output               | `caps.hasSpeaker`    |
| **Button**     | Physical controls          | `caps.hasButton`     |
| **LED**        | Light indicators           | `caps.hasLight`      |
| **IMU**        | Motion sensors             | `caps.hasIMU`        |
| **WiFi**       | Network connectivity       | `caps.hasWifi`       |

## Basic Usage

```typescript theme={null}
protected async onSession(session: AppSession, sessionId: string, userId: string) {
  const caps = session.capabilities;
  if (!caps) return;

  // Adapt to available hardware
  if (caps.hasDisplay) {
    session.layouts.showTextWall('Welcome!');
  } else {
    await session.audio.speak('Welcome!');
  }

  if (caps.hasCamera) {
    session.logger.info('Camera available');
  }
}
```

## Detailed Capabilities

### Display Details

```typescript theme={null}
if (caps.hasDisplay && caps.display) {
  session.logger.info('Resolution:', caps.display.resolution);
  session.logger.info('Color:', caps.display.isColor);
  session.logger.info('Max text lines:', caps.display.maxTextLines);
}
```

### Camera Details

```typescript theme={null}
if (caps.hasCamera && caps.camera) {
  session.logger.info('Resolution:', caps.camera.resolution);
  session.logger.info('Can stream:', caps.camera.video.canStream);
  session.logger.info('Can record:', caps.camera.video.canRecord);
}
```

### LED Details

```typescript theme={null}
if (caps.hasLight && caps.light) {
  session.logger.info('LED count:', caps.light.count);

  caps.light.lights?.forEach(led => {
    session.logger.info(`${led.id}: ${led.isFullColor ? 'RGB' : led.color}`);
  });
}
```

## Common Device Types

**Display Glasses** - Have screens, no camera:

* Even Realities G1
* Vuzix Z100

**Camera Glasses** - Have cameras, no display:

* Mentra Live

See device-specific pages for details:

* [Display Glasses](/app-devs/core-concepts/hardware-capabilities/display-glasses)
* [Camera Glasses](/app-devs/core-concepts/hardware-capabilities/camera-glasses)

## Adapting Your App

```typescript theme={null}
protected async onSession(session: AppSession, sessionId: string, userId: string) {
  const caps = session.capabilities;
  if (!caps) return;

  // Choose interaction mode
  if (caps.hasDisplay) {
    this.useVisualMode(session);
  } else if (caps.hasSpeaker) {
    this.useAudioMode(session);
  }

  if (caps.hasButton) {
    this.enableButtonControls(session);
  }
}
```

## Capabilities Interface

```typescript theme={null}
interface Capabilities {
  modelName: string;

  hasCamera: boolean;
  camera: CameraCapabilities | null;

  hasDisplay: boolean;
  display: DisplayCapabilities | null;

  hasMicrophone: boolean;
  microphone: MicrophoneCapabilities | null;

  hasSpeaker: boolean;
  speaker: SpeakerCapabilities | null;

  hasIMU: boolean;
  imu: IMUCapabilities | null;

  hasButton: boolean;
  button: ButtonCapabilities | null;

  hasLight: boolean;
  light: LightCapabilities | null;

  hasWifi: boolean;
  power: PowerCapabilities;
}
```

## Best Practices

**Always check capabilities:**

```typescript theme={null}
// ✅ Good
if (session.capabilities?.hasCamera) {
  session.logger.info('Camera hardware is available');
}

// ❌ Avoid - assuming every glasses model has the same hardware
this.enableEveryHardwareFeature();
```

**Provide fallbacks:**

```typescript theme={null}
if (caps?.hasDisplay) {
  session.layouts.showTextWall('Message');
} else {
  await session.audio.speak('Message');
}
```

**Check null values:**

```typescript theme={null}
// Capabilities may be null initially
if (!caps) {
  session.logger.warn('Capabilities not available');
  return;
}
```

## Next Steps

<CardGroup cols={2}>
  <Card title="Display Glasses" icon="display" href="/app-devs/core-concepts/hardware-capabilities/display-glasses">
    G1, Vuzix - display-specific features
  </Card>

  <Card title="Camera Glasses" icon="camera" href="/app-devs/core-concepts/hardware-capabilities/camera-glasses">
    Mentra Live hardware capabilities
  </Card>

  <Card title="Capabilities Reference" icon="book" href="/app-devs/reference/interfaces/capabilities">
    Complete capabilities types
  </Card>

  <Card title="Device Control" icon="microchip" href="/app-devs/core-concepts/app-session/device-control">
    Using device features
  </Card>
</CardGroup>