docs(connectors): survey voice wearables for the next connector

[nikhilcrypto0]

Closes #13

Adds docs/connectors/wearable-survey.md, which compares nine devices or projects and recommends one next connector.

Acceptance criteria

Criterion	How
Primary vendor, protocol, SDK and repository sources	Every row links vendor pages, official docs, SDK repos, or LICENSE files. Press coverage is used only for the two acquisitions and is labelled R.
Transport, audio access, platforms, SDK/API, auth, background limits, availability	Summary table plus one section per candidate.
License of adaptable code or protocol material	Per candidate, from the LICENSE file or the README's own license statement.
Facts vs experiments and assumptions	Every fact is labelled D (documented), R (reported), or U (unverified). No hardware was tested, so there are no experimental claims.
Offline / BYOK	Noted per candidate where documented; otherwise U.
One recommendation with tradeoffs	MentraOS (session.mic.onAudioChunk(), Apache-2.0, sold today, and it abstracts Mentra Live, Even Realities G1/G2 and Vuzix Z100). Runner-up: Brilliant Labs Halo.
No proprietary code; no support promised from marketing	No code is included. Plaud and Bee are rejected on documented facts, not marketing claims. Reverse-engineered G1 notes are listed only to note they exist.

Findings that change the picture

• Plaud: the sample app is Apache-2.0, but the README states the SDK binaries are proprietary. Its documented PCM is delivered during file sync; a live stream is not documented.
• Mentra: raw audio is session.mic.onAudioChunk() and arrives as PCM or LC3 depending on the phone's mic mode. A connector must read format / sampleRate per chunk rather than assume 16 kHz. It requires the MICROPHONE manifest permission.
• Halo: the firmware repository states it is "not uniformly Apache-2.0" because of the vendored Alif SDK license, which restricts use to Alif silicon.
• Excluded: Limitless (new sales ended after the reported Meta acquisition; its API only exports audio after the fact), Bee (processed data only, no raw audio), OpenGlass (merged into Omi).

Verification

Licenses, stars, last push and archive status were read from the GitHub API on 2026-09-25 for every cited repository. The load-bearing claims were re-fetched from the primary pages:

• Omi's protocol doc: Opus 16 kHz default since firmware v1.0.3;
• Mentra's audio-chunk doc and the Mentra Live store page;
• Plaud's SDK README;
• Halo's firmware README;
• Limitless's developer page.

Open question for the next step

Whether onAudioChunk needs a Mentra account, miniapp registration or the Mentra app, and whether the Bluetooth SDK starter kit reaches the microphone directly, is unverified. The survey marks it as the first task of any MentraOS connector, because it decides whether the connector can run fully locally.

[harshsaver]

Thanks @nikhilcrypto0, this is careful work. I spot-checked every GitHub citation and the main vendor pages. Omi's codec table and the v1.0.3 Opus default, the Mentra PCM/LC3 wording and MICROPHONE permission, the Halo/Alif license quotes, Plaud's proprietary-binaries line, Limitless's 2-hour Ogg Opus export, Bee's processed-data-only proxy and the OpenGlass move all match their sources. The D/R/U labelling is a useful convention.

Please fix the Mentra recommendation before merge:

1. Recommend the Mentra Bluetooth SDK, not session.mic.onAudioChunk() (lines 24, 50–53, 128).

   • onAudioChunk is the Miniapp SDK. Mentra's overview says it is beta, that "there is currently no way to distribute a miniapp built with the Miniapp SDK", and that miniapps run inside the Mentra App. For Mentra Live it says: "we recommend using the Mentra Bluetooth SDK."
   • A Murmur connector can't live inside the Mentra App, so the Bluetooth SDK is our path.

2. Resolve the account-boundary U (lines 60–61, 144–146). The sources you already cite answer it:

   • The Mentra Live page says the Bluetooth SDK controls the mics, works offline and doesn't depend on Mentra cloud.
   • The starter kit's docs/audio-guide.md documents continuous mic_pcm/mic_lc3 events.
   • docs/api-reference.md lists sampleRate, channels and encoding on those events.
   • There is also docs/mentra-live-ble-wire-protocol.md.

   The real remaining open item is the license of the published SDK artifacts (com.mentra:bluetooth-sdk, MentraBluetoothSDK, @mentra/bluetooth-sdk). Please apply the same test you used for Plaud.

3. Narrow "one connector reaches a whole device category" (lines 137–138). The starter kit's docs/hardware-integration.md and audio guide list microphones only for Mentra Live and G2. Mark Z100/G1 audio as U.

Optional nits:

• Line 8: name the three candidates that "lost new-sale availability within ~nine months", or drop the claim (Bee's acquisition was July 2025, and the table still shows it as buyable).
• Lines 40, 56, 121: star counts and "active" will go stale. Drop or date them.
• Unlabelled or unsourced cells: line 28 "Closed", line 31 "Parts only", the "BYOK follows" inference at 58–59, and Bee "Buy new: Yes (R)" at line 29.
• Line 66: Halo shipments reportedly began in early August. Say that precisely.
• Line 90: Plaud's README advertises "Real-time recording with live PCM waveform". Mention it next to "live stream U".
• Line 48: Mentra Live retail ships to the US only.

[nikhilcrypto0]

Thanks for checking every source. All three points and the optional nits are addressed. main (with #50) is merged in rather than rebased, so no force-push; the PR is still one new file.

1. Mentra Bluetooth SDK, not onAudioChunk. The recommendation now targets Mentra Live through the Bluetooth SDK's mic_pcm events (16 kHz, 16-bit mono per the audio guide), with mic_lc3 optional. The Miniapp SDK is described as beta and not distributable, with Mentra's own "we recommend using the Mentra Bluetooth SDK" line quoted.
2. Account boundary. The U is replaced with the Mentra Live page's statement that the SDK controls the microphones, works offline and doesn't depend on Mentra-hosted cloud. I applied the Plaud test to the published artifacts:
   • The SDK source (mobile/modules/bluetooth-sdk in MentraOS) has an Apache-2.0 LICENSE.
   • com.mentraglass:bluetooth-sdk on Maven Central declares Apache-2.0 in its POM. The group is com.mentraglass, not com.mentra.
   • The mentra-bluetooth-sdk-ios package repo is Apache-2.0.
   • @mentra/bluetooth-sdk on npm declares MIT, which disagrees with the source LICENSE. Both are permissive; the survey flags the mismatch to raise with Mentra.
   • The Android module bundles lc3Lib and silero, whose licenses are marked U.
3. Device reach. Narrowed to Mentra Live and G2 microphones per hardware-integration.md; G1 and Z100 audio are U.

Optional nits

• The "three candidates" claim is replaced with the two named changes (Limitless, Frame → Halo).
• Star counts are removed, and activity is dated.
• The unlabelled cells ("Closed", "Parts only", the BYOK inference) now carry labels; I added an explicit Inference label.
• Bee's availability is now D from its own store ($49.99, Amazon branding), since you were right that it is still sold.
• Halo: "shipments beginning in early August", quoted from its product page.
• Plaud: "Real-time recording with live PCM waveform" is quoted next to the still-open general-purpose live-capture question.
• Mentra Live's US-only retail shipping is noted as a tradeoff.

[harshsaver]

Thanks @nikhilcrypto0, all three points are resolved. I re-checked the new claims against their sources:

• Mentra overview: the Miniapp SDK is beta and not distributable, and Mentra recommends the Bluetooth SDK.
• Mentra Live page: the offline / no-Mentra-cloud quote and US-only retail shipping.
• Starter kit: the mic_pcm 16 kHz / 16-bit / mono values, the mic_lc3 fields, the Live and G2 hardware table, and iOS 15.1+.
• Licenses: Apache-2.0 for the SDK source LICENSE, the Maven POM and the iOS repo. npm 3.1.1 declares MIT. lc3Lib and silero are in the Android module.
• Halo $399 and "early August", Bee $49.99 with Amazon branding, the Plaud README quotes, and the repo dates.

Everything matches. Merging.

Two small optional follow-ups, fine to leave for the implementation PR:

• Line 160: Plaud's blePcmData is also a documented stream with a format, so consider "the only candidate besides Omi with a documented microphone stream that needs no vendor account or proprietary binaries".
• Lines 170-171 (License details): the Android Maven artifact depends on Google's play-services-location and play-services-base, which are proprietary, and all published Maven versions are beta or dev builds. Worth listing next to the lc3Lib/silero item.