tui

Hardware & Physical Setup

Everything here is off-the-shelf. For the per-station shopping list with example products, see BOM.md in the repository.

The station

        ┌──────────── boom / stand / ceiling mount ────────────┐
        │                                                       │
     [projector] [webcam]      ← side by side, both pointing down
           \      |
            \     |              projector image  ≥ table area
             \    |              camera view      ≥ projector image
   ┌──────────\───|────────────────┐
   │      white matte table        │
   └───────────────────────────────┘
          [laptop] ── HDMI ── projector
                   ── USB  ── webcam

Projector

• Any HDMI projector works. Brightness matters more than resolution: a compact ~600 ANSI lumen projector (like the example in the BOM) is fine in a dimmed room; in a normally lit room aim for ≥ 3000 ANSI lumens. “LED lumens” or unqualified lumen figures on cheap projectors are often 5–10× optimistic.
• Native 1080p is ideal. Many budget projectors accept 1080p/4K but display 720p or less.
• Throw ratio decides how high it must be: image width = distance ÷ throw ratio.
  • Covering a 1.2 m wide table with a typical 1.2:1 projector needs ≈ 1.45 m of throw.
  • A short-throw (≈0.5:1) projector covers it from ≈ 0.6 m, which is much easier to mount.
• Turn off keystone correction and auto-keystone. We correct in software.
• Many projectors have a ceiling / rear projection mode that flips the image. Use it if the image is upside down or mirrored.
• Pointing a projector straight down can block its vents or void the warranty on some models. Check the manual, or use a 45° mirror to fold the light path down while the projector sits level.

Webcam

• USB webcam, 720p–1080p, wide field of view (≥ 78°) so it can see the whole table from close to the projector.
• Prefer fixed focus or a camera whose focus/exposure can be locked. Hunting autofocus and auto-exposure fight the tracker.
• Mount it as close to the projector lens as practical. The closer they are, the less objects’ shadows and parallax confuse things.
• Optional upgrade: a camera with no IR-cut filter, plus an IR-pass filter and IR illuminator solves the feedback problem (see concepts.md).

Computer

• Any laptop from roughly the last 6 years, with HDMI out (or a USB-C → HDMI adapter).
• Chrome or Edge (recommended), or Firefox / Safari (recent versions).
• Display mode: Extend, projector at native resolution, display scaling 100% if the OS allows.
• macOS: grant the browser camera access in System Settings → Privacy & Security → Camera.

Surface & room

• White, matte, flat. Glossy tables make a hotspot. A sheet of matte white foam board, paper or a white tablecloth on top fixes it.
• Darker is better, but you don’t need blackout. Avoid lights shining directly on the table.
• Keep the camera and projector rigid. A bumped mount means recalibrating. Gaffer tape is your friend.

Mounting options (cheapest first)

1. Tall tripod / light stand with a boom arm, projector and camera clamped at the end.
2. Desk-clamp monitor or camera arm reaching over the table.
3. Shelf or ceiling mount for permanent installs.
4. Mirror fold: projector level on a shelf, front-surface mirror at 45°. Watch out for double images from back-surface (bathroom) mirrors.

Power & cables

• Extension cord with enough outlets for projector + laptop.
• HDMI cable long enough to reach the mount (often 3–5 m).
• USB extension for the webcam: use an active (powered) extension beyond ~3 m.