No network between them

The file travels on the light of a screen.

One phone shows it as a run of changing codes. The other films them and puts the file back together. No cable, no account, no internet between them.

Nothing leaves your browser

How it happens

How it works

The first phone turns the file into a run of codes that change quickly on screen. The second films them and puts the file back together, piece by piece. No network runs between the phones, only the light from the screen.

  1. 01

    On the sending phone

    Pick the file and press Start. The screen begins to flicker.

  2. 02

    On the receiving phone

    Turn on the camera and hold it in front of the other screen.

  3. 03

    Wait

    The bar fills on its own. When it reaches the end, the file is saved.

A screen and a crowd

A screen that repeats, read by whoever walks past.

On a public screen it loops forever. Nobody presses anything and there is no session to begin. Whoever lifts a phone learns from the first code they catch how long the whole thing takes, and catches the rest before the lap closes.

36codes in one lap
3sis how long a lap runs
25 KBfrom a single black and white code
  • A stop's timetable
  • A restaurant's menu
  • A medicine's leaflet
  • The boarding gate
  • The notice on the board

Before you start

Worth knowing before you start

  • This page open on both phones

    There is nothing to install, but both phones have to sit on this page at the same time. The one with the camera only watches; it cannot ask for anything back.

  • The screens have to stay awake

    If the sending screen goes dark or the phone sleeps, sending stops. Set the screen timeout as long as it goes and do not switch to another app.

  • Big files take minutes, not seconds

    Far less goes through a screen than through a cable. A photo or a document is quick. A file of tens of MB keeps both phones busy for several minutes.

  • The file never leaves the phone

    It reaches no server, and the two phones need no internet between them. Once the page has loaded you can switch mobile data off.