Use of Infrared responsive marker and edge lighting

[cefn]

Thanks, Dave. Below is the email outlining his idea. He really must get a github account :)

---------- Forwarded message ----------
From: David Chatting
Date: 20 September 2010 18:43
Subject: invisible calendar markers
To: Cefn Hoile
Hiya - was thinking about your comment at dorkbot about how you might use a digital camera and markers to import the data...

Now this is definitely a "making it more complicated" solution, but I was thinking if you could have an invisible marker that only shows up on the camera, by using IR light. Arranged something like the edge-lit Christmas Cards - http://www.evilmadscientist.com/article.php/edgelitcards