I've always loved those LED signs you see in store windows and many other places, that happily flash advertisements at you. Althought I'm not a big fan of the ads, I did appreciate the coolness of the signs. When a recent trip to a local surplus store netted some cool but basic LED signs, I decided that it was worth the investment for a proper one with a documented interface. Several hours of searching the net and eBay led me to the Alpha 4120C sign, which I netted on eBay for a mere $275 (MSRP is $1800+). The Alpha sign protocol is fully documented, and the signs are quite capable.
After two or three days of fiddling and testing, and nearly blowing out the communications board, I got the sign doing exactly what I wanted.
I assembled this short video to demo the features I've programmed into the sign thus far.
The SoftwareBased on the protocol manual, I wrote a relatively simple tag-based language and some basic commands that make interfacing with the sign really easy. Here are some excerpts from my Alpha Sign Communications Library:
A simple display of text in file "A":
ALPHA_newTextFile ALPHA_addText "Sign is ready." ALPHA_finishTextFile "A"
This is the code that is used for when a new song begins:
ALPHA_newTextFile ALPHA_addText "<STARBURST>" ALPHA_setCurrentLine lineTop ALPHA_addText "<SNOW><C:RED><F:SANS7>" ALPHA_addText "<STRING>G" ALPHA_addText "<NOHOLD>" ALPHA_setCurrentLine lineBottom ALPHA_addText "<ROLL:UP><C:GREEN><F:SANS7>" ALPHA_addText "<STRING>S" ALPHA_finishTextFile "B"
This code loads a 120x16 picture (seen below) into the sign:
ALPHA_loadPictureIntoMemory "Z", App.Path & "\later.bmp", ALPHA_3Color
I've finally decided to open-source my Alpha library. You can grab it here: Alpha Sign Communications Library