If you need to leave someone a message, you could either entrust it to a Post-It note or you could go the slightly more obvious route and use a 12-foot long LED matrix. That's what kitesurfer did, using a total of 512 blue LEDs and a slab of frosted acrylic to make a 20-inch high display that runs the length of his home office.
Video demos after the cut
An ATMEL Mega8 controls the various LED arrays, and gets its commands from a Linux-based embedded computer. That also runs a basic webserver, meaning that messages can be set via a website or even your smartphone.
Altogether the project cost around €200 ($273) though half of that was the lengthy sheet of acrylic that covered the front of the matrix.
[via Hack a Day]