device-features

name	device-features
description	Use G2 hardware features in Even Hub apps — microphone audio capture, IMU motion data, device info, user info, and local storage. Use when working with audio, IMU, battery, wearing detection, or persistent storage.
allowed-tools	["Read","Grep","Glob","Bash","Write","Edit"]
argument-hint	["feature task description"]

You are implementing G2 hardware feature integration for an Even Hub app. Use the reference below to implement exactly what $ARGUMENTS describes.

Prerequisite

createStartUpPageContainer must succeed before calling audioControl or imuControl. Both features depend on the startup page container being established first.

---

Audio Capture

Start the microphone with await bridge.audioControl(true) and stop it with await bridge.audioControl(false).

Audio data arrives through the onEvenHubEvent listener. Access it via event.audioEvent.audioPcm, which is a Uint8Array.

Format: PCM, 16 kHz sample rate, signed 16-bit little-endian, mono channel.

// Prerequisite: createStartUpPageContainer must succeed first
await bridge.audioControl(true)

const unsubscribe = bridge.onEvenHubEvent(event => {
  if (event.audioEvent) {
    const pcm = event.audioEvent.audioPcm // Uint8Array
    // Process PCM data (Web Audio API, speech recognition, etc.)
  }
})

// Stop and clean up
await bridge.audioControl(false)
unsubscribe()

---

IMU Control

Start IMU reporting with await bridge.imuControl(true, ImuReportPace.P500) and stop with await bridge.imuControl(false).

ImuReportPace enum values: P100, P200, P300, P400, P500, P600, P700, P800, P900, P1000. These are protocol pacing codes, not literal Hz values.

IMU data arrives via onEvenHubEvent. Access it through event.sysEvent.imuData, which has the shape { x: float, y: float, z: float }. Filter events by checking sys.eventType === OsEventTypeList.IMU_DATA_REPORT.

import { ImuReportPace, OsEventTypeList } from '@evenrealities/even_hub_sdk'

await bridge.imuControl(true, ImuReportPace.P500)

const unsubscribe = bridge.onEvenHubEvent(event => {
  const sys = event.sysEvent
  if (!sys?.imuData) return
  if (sys.eventType !== OsEventTypeList.IMU_DATA_REPORT) return
  const { x, y, z } = sys.imuData
  console.log('IMU:', x, y, z)
})

await bridge.imuControl(false)
unsubscribe()

---

Device Info

await bridge.getDeviceInfo() returns a DeviceInfo object or null.

DeviceInfo fields:

• model — DeviceModel enum (DeviceModel.G1 = "g1", DeviceModel.G2 = "g2", DeviceModel.Ring1 = "ring1")
• sn — serial number string
• status — a DeviceStatus object

DeviceStatus interface fields:

• sn — serial number
• connectType — a DeviceConnectType enum value
• isWearing? — boolean, whether the user is wearing the device
• batteryLevel? — integer 0–100
• isCharging? — boolean
• isInCase? — boolean

DeviceConnectType enum values: None, Connecting, Connected, Disconnected, ConnectionFailed

DeviceStatus helper methods: isNone(), isConnected(), isConnecting(), isDisconnected(), isConnectionFailed()

For real-time status updates, subscribe with bridge.onDeviceStatusChanged:

const unsubscribe = bridge.onDeviceStatusChanged(status => {
  console.log('Battery:', status.batteryLevel)
  console.log('Connected:', status.isConnected())
})

Call unsubscribe() to stop listening.

---

User Info

await bridge.getUserInfo() returns a UserInfo object.

UserInfo fields:

• uid — number, unique user identifier
• name — string, display name
• avatar — string, URL to the user's avatar image
• country — string, user's country code

---

Local Storage

Persist data to the Even Realities App (survives app restarts):

• await bridge.setLocalStorage(key, value) — stores a string value; returns boolean indicating success
• await bridge.getLocalStorage(key) — retrieves a stored string; returns an empty string if the key does not exist

SDK localStorage is the only reliable persistence

The Even App WebView is a Flutter WebView. Browser IndexedDB and browser localStorage do NOT reliably persist across app restarts in this environment — data saved there can be lost when the user closes and reopens the app.

Use bridge.setLocalStorage / bridge.getLocalStorage for all user state: settings, progress, bookmarks, preferences, cached content. For large content (e.g. ebook text), chunk it across multiple keys:

const CHUNK_SIZE = 50_000  // chars per key
const PREFIX = 'myapp.content_'

async function saveContent(bridge: EvenAppBridge, id: string, text: string) {
  const chunks = Math.ceil(text.length / CHUNK_SIZE)
  await bridge.setLocalStorage(`${PREFIX}${id}_n`, String(chunks))
  for (let i = 0; i < chunks; i++) {
    await bridge.setLocalStorage(
      `${PREFIX}${id}_${i}`,
      text.slice(i * CHUNK_SIZE, (i + 1) * CHUNK_SIZE),
    )
  }
}

See glasses-ui → Best Practices for debouncing and serializing bridge writes.

---

Cleanup on Exit

Always stop hardware features and unsubscribe event listeners when the app exits or is destroyed. Failing to do so may leave the microphone or IMU running on the glasses hardware.

// Store all unsubscribe functions and stop hardware on exit
window.addEventListener('beforeunload', () => {
  bridge.audioControl(false)
  bridge.imuControl(false)
  unsubscribe() // from onEvenHubEvent
})

Apply the same pattern for any hardware feature that requires explicit stop/start control (audioControl, imuControl).

---

What the SDK Does NOT Expose

The following capabilities are not available through the Even Hub SDK:

• No direct Bluetooth access
• No arbitrary pixel drawing
• No audio output (there is no speaker)
• No text alignment control
• No font control
• No background colors
• No per-item list styling
• No programmatic scroll position
• No animations
• No camera (there is none on G2)
• Images are greyscale only

---

Task

$ARGUMENTS