Research Preview — not a medical device and not proven to prevent motion sickness.

InertialLink XR is an open protocol, Android motion sender, and Unity/OpenXR package for driving an explicitly selected virtual environment root from a vehicle-mounted phone. It keeps the headset's normal head tracking separate from vehicle motion and gives researchers and XR developers a small, auditable integration surface.

Stationary Xiaomi XIG04 to Unity 6000.1.14f1 validation: 216 authenticated packets accepted, 0 rejected, 2,019 directional cues, and Camera pose unchanged. This verifies the integration path, not human comfort or efficacy.

Build Week showcase · 日本語 · Protocol · Integration guide · Safety · Security

The contest build moved InertialLink XR from an architecture proposal to a working Android-to-Unity path. In a stationary Xiaomi 13T validation, Unity accepted 216 authenticated motion packets with 0 rejected or dropped, rendered 2,019 directional background cues around a fixed vertical video, and left the Camera pose unchanged. A separate Play Mode run also measured a deliberately introduced physical-versus-virtual acceleration mismatch and produced a bounded, report-only correction suggestion.

The same external motion reference can support more than passenger-comfort research: it can help inspect digital-twin alignment, calibrate simulators, and check whether motion-platform output matches a virtual scenario. These are future application directions, not completed product validations.

• Read the illustrated project story, evidence, and future uses
• Watch the demo
• View the Devpost submission
• Download the v0.2.0 Research Preview

Passenger use only. Never use or configure a headset while driving, cycling, walking, or controlling machinery. Stop immediately if you feel discomfort. The project makes no claim that its cues prevent, treat, or reduce sickness for any particular person.

• An Android sender using acceleration, gyroscope, gravity, linear acceleration, and rotation-vector sensors—without camera, GPS, microphone, account, cloud, advertising, or telemetry permissions.
• A versioned, big-endian UDP protocol with an ephemeral 128-bit pairing key, truncated HMAC-SHA-256 authentication, replay rejection, clock sync, strict bounds, and stale-data rejection.
• A Unity 2022.3 LTS+ package that exposes validated motion samples and can drive only a deliberately assigned content root. It refuses to drive a Camera or XR Origin hierarchy.
• Dependency-free Node.js tools for deterministic synthetic signals, packet inspection, protocol tests, and recording validation.
• Synthetic recordings and documentation for repeatable development without collecting real passenger or location data.
• A directional star-grid sample that keeps a 9:16 video fixed while a curved, perspective-converging background conveys vehicle motion, plus a diagnostic monitor for measured-versus-virtual acceleration mismatch and bounded correction suggestions.

It does not provide a Quest-wide/system overlay, replace OpenXR head tracking, infer location, reconstruct a vehicle trajectory, or make arbitrary third-party applications move. Applications opt in and choose exactly which content consumes motion data.

Peer-reviewed on-road/on-vehicle studies have reported lower sickness with vehicle-synchronized peripheral or background visual cues. Recent work also reports that sparse acceleration-based cues can reduce distraction during tasks such as watching a movie. InertialLink XR turns that research direction into a reusable Unity/OpenXR integration layer; it does not claim that this implementation has independently reproduced the human-subject results.

See Research basis and claim boundary for the cited 2022 HFES, 2024 IEEE Access, 2017 CHI, and 2026 Applied Ergonomics studies.

vehicle-fixed Android phone                 XR application
┌──────────────────────────┐    local UDP   ┌────────────────────────────┐
│ sensors → mount transform├───────────────►│ authenticated receiver     │
│ ephemeral pairing key    │   ILXR v1.0    │ replay/age/range checks    │
└──────────────────────────┘◄───────────────┤ clock synchronisation      │
                                            │ VehicleMotionHub           │
headset tracking ──────────────────────────►│ OpenXR Camera/XR Origin    │
                                            │ selected contentRoot only  │
                                            └────────────────────────────┘

The wire coordinate system is OpenXR-style right-handed: +X right, +Y up, and -Z forward. All transport values use SI units. See the normative protocol specification.

Requirements: Node.js 24+ and Unity 2022.3 LTS or newer. Android development additionally requires JDK 17 and the Android SDK.

1. Generate a temporary 16-byte key. Do not reuse this documentation value outside loopback testing:

   00112233445566778899AABBCCDDEEFF
   

2. In one terminal, run the loopback-only inspector:

   node tools/packet-inspector.mjs --key 00112233445566778899AABBCCDDEEFF

3. In another terminal, send a bounded synthetic turn:

   node tools/synthetic-sender.mjs --key 00112233445566778899AABBCCDDEEFF --scenario gentle-turn --seconds 10

4. Run the repository checks:

   npm run check

Both tools bind to loopback by default and refuse non-loopback networking unless --allow-network is explicitly supplied. Non-loopback Node use also requires the one-session key in ILXR_PAIRING_KEY; --key is reserved for public-vector loopback tests. They never read device sensors.

Next, follow Unity integration, then Android setup, and complete the calibration checklist before any stationary-vehicle test. Do not begin with a public-road or public-transport trial.

The exact automated and manual verification coverage—and the gaps that remain—is recorded in Validation.

Safety before motion fidelity. Invalid, unauthenticated, replayed, future, or stale packets cannot refresh the receiver's safety timer. When valid input stops, output fades to neutral; it never holds the last motion indefinitely.

Private by default. Motion stays on the local link. There is no discovery broadcast, remote service, analytics, GPS, or user account. HMAC authenticates packets but does not encrypt them; use a private link or a trusted tunnel if motion-data confidentiality matters.

Integration, not global control. The Unity driver modifies only the assigned content transform. It must not be placed above a Camera, XR Origin, or unrelated application UI. See limitations.

InertialLink XR was created during OpenAI Build Week in a Codex session using GPT-5.6. The builder set the product constraints and safety boundaries; Codex helped turn them into a cross-language implementation, tests, documentation, and release automation.

Codex accelerated the work by:

• decomposing the idea into a versioned wire protocol, Android sender, Unity package, and dependency-free synthetic tools;
• implementing shared authenticated packet vectors across Kotlin, C#, and Node.js, then adding failure-path tests for tampering, replay, stale data, invalid numbers, and safe fade-out;
• reviewing the permission and data-flow surface so the Android app could ship without camera, microphone, location, account, advertising, or telemetry permissions; and
• producing reproducible validation notes and release artifacts while clearly separating verified checks from unavailable hardware and human testing.

The key product decisions remained explicit human choices: use a vehicle-mounted phone as an external vehicle-motion reference; preserve normal head tracking; modify only an opt-in content root; fail closed on invalid or missing data; and make no motion-sickness efficacy claim. See the detailed Build Week collaboration record.

The v0.2 goal is interoperability and safe failure behavior, not an efficacy claim. APIs and wire-protocol minor versions may evolve. Compatibility rules are documented in the specification, and planned work is tracked in the roadmap.

Security reports should follow SECURITY.md. General changes are welcome under CONTRIBUTING.md and the Code of Conduct.

Apache License 2.0. See LICENSE, NOTICE, and third-party notices.