Relativty: An open-source VR headset for $200

Original Article ↗ Hacker News Discussion ↗

Product name, branding, and searchability

  • Many find “Relativty” (missing an “i”) confusing, hard to spell, and worse for discoverability due to autocorrect.
  • Some argue a clearer name like “RelativityVR” would better communicate purpose and be easier to communicate, especially for non‑native speakers.
  • The domain choice and later rebranding toward “Unai”/unison.co are noted and questioned.

DIY nature, real cost, and hobby value

  • Key point: it’s not a $200 retail headset; it’s a DIY build using ~$200 in parts, plus 3D printing and soldering.
  • Several comments stress hidden costs: tools, printer, consumables, failed prints, missing small parts, lack of warranty.
  • Others counter that for hobbyists the build process is the point, and “time cost” is outweighed by fun, learning, and customization.

3DoF vs 6DoF tracking debate

  • Many argue 3DoF (rotation only) is now inadequate for “real VR”; 6DoF is seen as minimum for comfort, immersion, and avoiding motion sickness, even when seated.
  • Some say 3DoF is acceptable for limited use cases: movies, simple sit‑down experiences, or as a head‑mounted display.
  • Lack of tracked controllers is repeatedly cited as a major limitation, making it closer to a movie viewer than a modern VR system.
  • A related open‑source project (HadesVR) is mentioned as a 6DoF evolution derived from this work.

Tracking technology and technical constraints

  • Multiple explanations describe why IMU‑only (accelerometers/gyros) positional tracking fails: rapid drift, error accumulation, and need for external references.
  • Modern 6DoF systems fuse IMUs with multiple cameras and SLAM; phones’ rolling shutters and power budgets make robust mobile tracking hard.
  • Extra sensors like magnetometers, GPS, or LiDAR help in other domains but generally don’t achieve required indoor, millimeter‑level accuracy alone.

Comparisons to commercial headsets and use cases

  • Some argue a $300 Meta Quest 3S or used 6DoF headsets are better value for general users.
  • Others are specifically interested in:
    • A lightweight, high‑resolution head‑mounted display for movies or FPV drone flying.
    • Future “monitor replacement” scenarios or programming in VR/AR.
  • Privacy and mandatory account concerns around commercial headsets, especially Meta, are raised and disputed.

Ecosystem, future, and reception

  • The project is praised as a learning platform and classroom/club project.
  • Skeptics doubt traction without 6DoF and controllers, but enthusiasts see strong maker appeal and view it as a stepping stone toward more open VR hardware.