Pairing a screen

What pairing is

Mirra comes in two halves that start out strangers. The screen app runs on the display and knows nothing about you. The portal knows everything about you and, until you tell it, nothing about the display. Pairing is the moment those two are introduced — the display stops being anonymous and becomes one of your screens.

It only ever goes one way. The display shows a code and waits; you type that code into Mirra while signed in. The display cannot claim itself, and that is deliberate — a screen that could join a household on its own is a screen anybody walking past could take.

What can act as a screen

The screen half of Mirra is a web page, so anything that can run a browser full screen and stay awake can be a screen. That is why an old laptop is a legitimate way to start and why there is nothing to install on a monitor.

Mirra asks what you are putting it on before it asks for a code, because the answer changes what you have to do first.

• A browser on a computer — free, and the fastest way to see whether you like it. The camera and microphone work, so the assistant, presence and gestures can be tried. It ties up a computer, and sleep, screensavers and updates will interrupt it.
• A Raspberry Pi — the recommended permanent version. It boots straight to Mirra, a watchdog restarts the browser if it dies, and it is the only route that supports wired buttons.
• A mini PC — the most capable. Live camera video rather than a still every second or two, and music playing out of the mirror itself. It costs two to four times what a Pi does and has no pins, so wired buttons stay Pi-only.
• A smart TV — no extra hardware at all, and the least predictable route. Most TVs have no camera or microphone, many sleep or close the browser on a timer, and nothing will restart them.
• Mirra Compute Device and Mirra Mirror Display — listed in the picker and marked coming soon. You can open either card and read what it will be, but neither can be paired: the card says there is nothing to pair yet and offers you the way back.

The two forthcoming products are shown rather than hidden because people plan around what they can see coming. Choosing either one offers you nothing to type — the code box does not appear.

Pair a screen

1. Open the screen app on the display

   Go to screen.twinassistant.com in a browser on the display and put it full screen — F11 on most machines, ⌃⌘F on a Mac. A Pi or mini PC set up with the installer does this for you at boot. A six-character code appears.

2. In Mirra, open Screens

   Screens is the first item in the navigation. Anything you have paired already is listed there, one card each, marked online or offline.

3. Click Pair a screen

   Mirra asks what you are putting it on first. Pick the card that matches. Each one lists what is good about it and what to know first, at the same size — the second list is the one that saves you an afternoon.

4. Type the code

   Enter the six characters showing on the display. Case does not matter; Mirra uppercases what you type. The Pair button stays disabled until there are six of them.

5. Name the screen

   Something you would say out loud — Kitchen, Hallway, Reception. Left blank it is called New screen. This is the name Identify screen puts on the wall later, so a name that distinguishes it from three identical panels is worth a moment.

6. Click Pair

   The display is asking Mirra every three seconds whether it has been claimed, so it switches to your layout within a few seconds. Nothing needs restarting at either end.

The code, and how long it lasts

The code is six characters drawn from an alphabet with the ambiguous ones taken out — no I, no L, no O, no zero and no one. It is meant to be read off a wall from across a room and typed on a phone, and those five characters are where that goes wrong.

Each code lives ten minutes. While it waits, the display asks Mirra every three seconds whether anybody has claimed it, and when a code expires unclaimed the display replaces it with a fresh one almost at once. So a code you wrote down five minutes ago may not be the one on the wall any more. Read it again rather than trusting your notes.

A code can be claimed once. After that it is spent, whatever its expiry says.

Mirra allows twenty pairing attempts in ten minutes from one address, then answers "Too many pairing attempts. Try again shortly." It is there to make guessing codes pointless, and it is generous enough that ordinary mistyping never reaches it.

When the code is refused

Four refusals are possible, and each one says something different.

• "That code isn't valid — check the screen for a fresh one." The code has expired, has already been claimed, or was mistyped. Look at the display and type what is on it now.
• "This screen is already paired." That display belongs to a household already — possibly yours, from an earlier attempt. Unpair it there first, or reload the display so it starts a new session.
• "Too many pairing attempts. Try again shortly." The rate limit. Wait, then try once, carefully.
• A refusal naming your plan's screen count. You have paired as many screens as the plan covers. Unpair one you are not using, or upgrade.

What pairing creates

Claiming a code does rather more than link two records, and it is worth knowing what now exists so that unpairing later is not a surprise.

• The display is bound to your household and given a token it keeps for a hundred and eighty days. The pairing secret it used to get there is dropped from its storage the moment it succeeds.
• A screen record: the thing that holds this display's shape, which way up it is, its camera and gesture settings, its schedule, and which scenes it shows.
• One scene called Main, set as its default, carrying a clock, the date, weather, an agenda, a photo frame and a note reading "Welcome to Mirra". A screen paired without a default scene would be a screen showing nothing at all.
• The weather in that starter scene is set to Durham until you change it, and the photo frame is empty until you point it at an album.

If your household has switched an integration off, that integration's widgets are trimmed out of the starter scene before the scene is saved. Otherwise pairing would put a calendar on the wall for a household that had turned Calendar off, and every later save of that scene would be refused for a widget nobody chose.

After it is paired

The screen fetches its whole configuration when it boots, again every minute, and immediately whenever you save something in the portal. That fetch is also its heartbeat: the Screens list calls a screen online if it has been heard from in the last ninety seconds, which is one minute's cycle plus a little grace.

From then on there is nothing to re-upload and nothing to restart. Three commands on the screen's own page cover the rest.

• Save & push in the editor writes the scenes you changed and tells the display to reload them.
• Identify screen puts the screen's name on the wall for five seconds — the way to tell which of four identical panels you have open.
• Reload screen reloads the browser on the display, which is the first thing to try when a change has not arrived.
• Rename, on the screen's card on the Screens list, changes the name everywhere it is used — the list, the screen's own page, and what Identify screen puts on the wall. A name you regret is not one you are stuck with.

Deleting a screen, and pairing again

Pairing the same display again gives you a new screen rather than the old one back. It gets a new identity, a new starter scene, and it counts as a fresh screen against your plan's allowance. That is the honest consequence of a display being able to prove nothing about its own past.

Deleting is also what to do when a screen is being moved to another household, or sold on. There is no transfer: the receiving household pairs it themselves, from a code it produces once it is no longer yours.

1. Open the screen's page

   From Screens, click the screen you want to remove.

2. Scroll to Danger zone

   At the bottom of the right-hand column, under the assistant face test.

3. Click Delete screen

   It is called Delete rather than Unpair because unpairing sounds like freeing the hardware and keeping the arrangement, and it does the opposite. Mirra counts before it asks, so the confirmation names what goes — the scenes, the schedule rules, any meetings sent to the screen's invite address, and any scene made for this screen that was never shared and would be left with nowhere to go. Delete also sits on the screen's card on the Screens list and asks the same itemised question, so you need not open the screen first.

4. Watch the display come back

   It is told to reload, finds it is no longer known, and starts a fresh pairing session with a new code.

Deleting a screen deletes the screen, not merely the link. Its shape, its rotation, its camera and gesture settings, its schedule rules and its list of scenes go with it. The scenes themselves stay in your household — but only a shared scene can be added to another screen, so an unshared scene whose screen has gone is not offered anywhere afterwards. If a layout took you an evening, share it before you delete.