This is a web app I put together over a couple of evenings that allows people to add messages to be displayed on a screen, using the Canvas Letters script I created a while ago.

It could be used at events to allow people to add messages via their phones/tablets/laptops, and have them displayed on a large screen, without having to sign up for an account/SMS/tweet/etc.

There are three parts to the app:

The form

This is the basic input form that allows people to add messages

The visualiser

This is the web page to load up on the screen/projector, to display the messages


An administration area to allow you to manage which messages are shown, and also archive old messages so the system can be re-used at a later date without having to touch the files on the server.

Set up is quick, just add the files to a web server, and edit the config.ini.php and add your MySQL database access details.

There are also a couple of configurable options:

  • moderate: Moderate all new messages and only display those that pass (the rest can be toggled via the admin section)
  • repeatMessages: If set to true, it will repeat a random old message if no new ones have come in. If set to false it will wait for a new message before updating the display

It is possible to password-protect the admin pages via .htaccess / .htpasswrd - there are sample files in the admin directory

This was just a quick proof-of-concept project, there are a lot of potential updates. It doesn’t use any libraries so it’s fairly lean, but very basic. It should really use websockets instead of polling for content. Etc…

Desktop Screenshots

Mobile Screenshots