People in front of the screen

A screen in a foyer can do more than loop: when someone stops in front of it, it can play something for them — a welcome, a product demo, the way to the room — and go back to its program when they walk on. In Wunderframe that is an ordinary rule: the screen's camera is one more thing a rule can ask about — Someone in front of the screen.

The camera only asks one thing: is there a face, and is it big (close) enough?

On Get started, choose the quick start Someone in front of the screen and one of its two presets:

• Lobby — the news from a feed rolls all day; when someone steps close, a Welcome screen with your words appears, and when they leave the news comes back.
• TV — a TV channel plays all day; when someone steps close, the news rolls; when they leave, the channel comes back.

Pick the stage (the screen with the camera) and how close someone must be. It makes both stories, turns the stage's camera on and adds the rule — ordinary content you can change afterwards. Either side can also be a story you already have. Then open the stage preview, set In front to Use my camera and step close to your webcam.

Presence is not a cut, a shot or a scene of its own. It is a condition, and a rule that asks it can live in one of two places, depending on how much should change:

• A stage rule — on Stages → the stage → When … play …. It switches the whole story on the screen to another story (or black, or a TV channel), and back after Keep playing after they leave. Example: someone in front → play Welcome.
• A block's rule — in the shot editor: select a block → Rules. It changes one block inside the shot — an image appears, a text hides, a color changes — while the shot keeps playing, and the block goes back to how you designed it when they leave. Example: show the QR code while someone is there.

Both read the same camera, so both need Notice people in front of the screen turned on for the stage. Use a stage rule when the moment deserves its own story; use a block's rule for a small change in a story that keeps running.

1. Open the stage on Stages and turn on Notice people in front of the screen. Choose how close someone must be, and how long to keep playing after they leave (10 seconds unless you say).
2. In the same dialog, add a rule: When Someone in front of the screen — someone is there — play the story for them.
3. Plug a webcam into the screen, pointed at the people in front of it.

The story plays while they stay. Once nobody has been there for Keep playing after they leave, the screen goes back to what it would play anyway — its bookings or its all-day story. A take on the Live board still wins over any rule.

1. Turn on Notice people in front of the screen for the stage, as above.
2. In the shot editor, select the block — say, a picture with a QR code — and open Rules.
3. Add a rule: while Someone in front of the screen — someone is there — show the block (and hide it the rest of the time), or change its color or text.

The shot keeps playing as designed; only that block reacts.

You do not need a camera to see a presence rule work. Every preview — the shot and layout previews in the editor, the story preview and the stage preview — has the Time & sensors bar underneath. Its In front choice pretends what the camera sees:

• No camera — as in the editor: no presence rule holds.
• Someone there — someone arrived now; the bar counts how long they have been there, so a rule for someone has been there 10 seconds takes effect ten seconds later.
• Nobody there — the room is empty.

The stage preview also lists the stage's rules and marks the one that holds. The preview wears SIMULATED while you pretend; no screen changes.

Use my camera (the fourth choice) tests the real thing at your desk: the preview runs the same face detection as a screen on your computer's webcam, with the stage's distance. The bar shows what it sees — face 0.18 · needs 0.22 → nobody there — so you can lean in and watch the rule switch at the distance the screen will use. Nothing leaves your browser; choosing anything else turns the camera off.

The screen counts a face only when it is big enough in the camera's picture, so people passing at the back of the room never switch it:

• Close — about 1 m: someone standing right at the screen.
• Near — about 2 m: someone stopping in front of it.
• In the room — about 4 m: anyone facing it from nearby.

A rule can also ask someone has been there … seconds — to start a longer story only for people who stay — or nobody is there.

• Android TV boxes and Android screens — a built-in camera, or any USB (UVC) webcam. The first time, the screen asks for the camera and for the USB webcam; answer with the remote and tick Always open Wunderframe for this device so it never asks again. A box the Wunderframe app manages grants the camera itself.
• Raspberry Pi — a USB webcam or the Raspberry Pi Camera Module.
• A browser on the player link — the browser's camera, after you allow it.

Devices shows each screen's camera: on, how many times a second it looks, whether someone is in front — or why it is not running (no camera found, permission denied). Unplugging the camera stops the rule; plugging it back in resumes it.

The panels of a video wall do not use their cameras: each would see a different room.

Looking takes processor time, so a screen looks slowly at an empty room and quickly only when someone arrives or stays. It measures how long each look takes and never lets the camera use more than its share of the processor: an old box looks less often rather than make the video stutter. Video always comes first.

Per screen, on Devices → the screen → settings: Camera — When the stage asks for it or Never on this screen (a weak box, or a screen that should never look) — and Camera load: Low (at most twice a second, for old boxes), Normal (four times) or High (eight times). Devices shows how often each camera looks and how long one look takes.

The camera's picture never leaves the screen and is never shown, stored or sent. The screen does not recognize, count or describe anybody: all it knows is someone is there, and since when. The camera is off unless the stage turns it on.

Noticing someone is one thing; letting them use the screen is another. On the stage, Visitors can use this screen turns on touch, a hand pointer from the camera, or both — a visitor then taps or points at an agenda row to open its detail, and swipes to the next. See Overview and detail, and the gesture guide that teaches them the hand gestures until they raise a hand.

Over MCP, set_stage_presence turns the camera on, and set_stage_rules adds a rule with the condition { "sensor": "presence", "op": "near" }. Over the REST API, PUT /api/v1/stages/{id}/presence with { "enabled": true, "distance": "close" }. set_stage_interaction lets visitors touch or point. A block's rule takes the same condition in its rules (update_block).