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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.

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Accessing Capabilities

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);
}

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Available Capabilities

CapabilityDescriptionCheck With
DisplayScreen for showing contentcaps.hasDisplay
CameraPhoto/video capturecaps.hasCamera
MicrophoneAudio inputcaps.hasMicrophone
SpeakerAudio outputcaps.hasSpeaker
ButtonPhysical controlscaps.hasButton
LEDLight indicatorscaps.hasLight
IMUMotion sensorscaps.hasIMU
WiFiNetwork connectivitycaps.hasWifi

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Basic Usage

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');
  }
}

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Detailed Capabilities

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Display Details

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);
}

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Camera Details

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);
}

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LED Details

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}`);
  });
}

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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:

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Adapting Your App

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);
  }

  // Enable features based on hardware
  if (caps.hasCamera) {
    this.enablePhotoFeatures(session);
  }

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

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Capabilities Interface

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;
}

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Best Practices

Always check capabilities: 
// ✅ Good
if (session.capabilities?.hasCamera) {
  await session.camera.requestPhoto();
}

// ❌ Avoid - may crash
await session.camera.requestPhoto();
Provide fallbacks: 
if (caps?.hasDisplay) {
  session.layouts.showTextWall('Message');
} else {
  await session.audio.speak('Message');
}
Check null values: 
// Capabilities may be null initially
if (!caps) {
  session.logger.warn('Capabilities not available');
  return;
}

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Next Steps

Display Glasses

G1, Vuzix - display-specific features

Camera Glasses

Mentra Live - camera-specific features

Capabilities Reference

Complete capabilities types

Device Control

Using device features