Intro
In a previous life, one of my jobs was to manage LED-signs for advertising purposes. You know, the red and sometimes red/green displays where cheesy texts advertising something or another are displayed on. The displays I worked on were mostly a bit bigger than the usual one-line small thingies, but the technology behind them generally was from previous century: a single 8-bit controller (usually an 8051) to handle all the multiplexed LEDs, some RAM to store the text in and a serial connection to program the unit. The displays could basically do only monochrome black/red-or-green text, and some could handle small graphics. If you wanted something with more capabilities, you usually went in video-wall territory, which meant a huge leap in price and amount of hardware. Even then, I thought a smart designer should be able to come up with something better...
A while later, I actually got a shot at developing an in-house based led-sign. It was a fun project, and I'm still sure it would have evolved into the Best LED-Sign In The World, but unfortunately, due to circumstances the project was aborted. The idea still was there, though: with some determination and smart coding, you should be able to build a sign that can display almost anything the LEDs are capable of displaying with hardware that's just a tiny bit more expensive than the hardware the standard, lame text-displays use.
A few months ago, while browsing the 'web for gadgets and other hackable hardware, I came across an offer for discounted, used LED-boards. The devices seemed to come from a bus stop display and basically consisted of a PCB with some logic and 8 8x8 LED-matrixes on it, making a neat 32x16 display. They were only 5 euros each so I decided to buy ten of them and see what I could make out of them.
Hint for the people with a short attention span: The next few pages get a bit technical. Go directly to page 5 and further to see the nice pictures and videos of the results.
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