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A camera wall on the workshop TV

Need states and completion times instead of video?

Use the status monitor: 50 uniform tiles on Full HD, attention-first ordering and separate printer/queue views. It has its own Status monitor TV token; the Cam Wall token in this scenario is for cameras.

The situation

Forty-eight printers in two rooms. The operator walks the rows to see what is going on; from the desk, the Printers page is a wall of cards and the cameras are one click each. A TV is already hanging in the shop. What it should show is every camera at once — and nothing a visitor should not read off a screen in a room anyone can walk into: no file names, no serial numbers, no addresses.

The goal

A URL that a TV, or a Raspberry Pi behind it, opens once and keeps showing: the whole farm as camera tiles with a state badge on each, no login, and revocable from Settings the day the TV is retired.

What is involved

Feature Its part
Camera wall The tile grid: live streams up to a cap, snapshots for the rest, paused off-screen.
Cam Wall on a TV or kiosk The wall's own URL, /camwall, and its token mode.
Long-lived tokens A Cam Wall-scoped token: the credential in the URL, revocable, at most a year old.

Step by step

  1. Try the wall signed in. On the Printers page switch Cards / Cam wall, or open http://your-bamdude:8000/camwall in your own browser. That is the full wall — tiles are clickable and the gear opens its settings. Note what looks right: how many tiles live at once, the snapshot interval.

  2. Make a token for the TV. Settings → API Keys → Camera and monitor tokens → create: name it after the screen — Workshop TV — scope Cam Wall, and an expiry (a year at most; never is refused by design). Copy the token: it is shown once.

  3. Build the URL.

    http://your-bamdude:8000/camwall?token=bblt_<prefix>_<secret>&maxLive=9&interval=10&status=compact

    maxLive is how many tiles stream live at once (1–16), interval the seconds between snapshot refreshes on the others (2–60), status the overlay — off or compact. A kiosk cannot open the settings gear, so the settings ride in the URL; a value out of range falls back to the default instead of breaking the wall.

  4. Point the TV at it. A browser in kiosk mode on the Pi, or the TV's own browser, full screen. That is all the configuration there is.

  5. Retire it one day. Settings → API Keys → Camera and monitor tokens, find Workshop TV by name or by its prefix, Revoke. The wall goes dark on its next request; there is no cache to wait out.

What BamDude does on its own after that

  • Only tiles on screen stream. A tile counts as visible once 40 % of it is on screen; the first maxLive visible tiles stream live MJPEG, the rest of the visible ones poll snapshots, and off-screen or disconnected printers pause entirely — no network, no ffmpeg process for a camera nobody is looking at.
  • The token wall is deliberately less than the signed-in wall. No click-through, no settings gear, the state badge only: the feed behind it does not serve print file names at all, so the part on the bed is never named to the room. Printer addresses and serial numbers are not served either. Archived printers do not appear; printers in maintenance mode still do — they are still on the farm.
  • Every viewer shares one stream. The TV's tile, your embedded viewer and a colleague's popup all read one fan-out stream per printer; closing one never freezes another, and the stream tears down only when the last viewer leaves.
  • A kiosk never writes settings back. Opening the kiosk URL in your own browser does not overwrite your own wall preferences — the URL parameters are read, not stored.
  • The token's last use is stamped (at most once a minute), so a token idle for 30 days gets a warning chip in Settings, and an administrator's All users section lists every live token on the install.

Pitfalls and what-ifs

The URL is the credential

Anyone who can read the URL — off the screen, out of the kiosk's config file, out of a browser history — can watch the wall. Treat it like a key: keep it out of screenshots, and revoke it the day a display is retired or a Pi goes missing.

  • A Cam Wall token opens only the wall. It is refused by the single-camera stream endpoint and by the OBS overlay, and a Camera-stream token is refused by the wall — the scopes are walls in both directions, so a token handed to a TV cannot be repurposed to pull one printer's stream with the file name on it.
  • A Raspberry Pi 4 tops out around four live tiles. Set maxLive to what the box actually decodes; the rest are snapshots and look nearly as good from across the room.
  • A full status overlay is not available on a token wall — it would show the file name. The URL accepts off or compact.
  • The wall cannot control a printer. Nobody is standing at the TV; pausing and stopping stay on the Printers page and in Telegram.
  • The token is tied to nothing but time. It is not narrowed per printer — a Cam Wall token shows every printer the wall shows. For a per-printer stream use an API key instead.