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The “Blinky” Animation

So I finally got around to opening up a box of goodies the other week, including a bunch of 8x8 bi-color (red & green) LED matrices from SureElectronics. I have had these things for about 5 years now, always imagining that I would build some cool scrolling marquis or something... only problem is I never got around to using them at all.

LED Matrix (bottom) LED Matrix (top)

As you can see from the pictures, the LED matrix has 24 pins. This accounts for 8 common cathodes, 8 red anodes, and 8 green anodes. The only thing that you probably cant grasp from those two pictures is the fact that there is no diffusing material between the LEDs and your view. This means that when you try to color-mix some combination of red and green, you dont really see orange. Instead you see a red dot and a green dot, and you go blind because they are really bright... why did you look directly into them? who knows.

Micrel MIC2981 NXP 8-bit shift register

The two chips you see there are the Micrel MIC2981 current/voltage source driver, and the NXP 8-bit shift-n-store register. The former is pretty straight-forward, providing an isolated source of current to drive the LEDs such that the current is not being drawn from the data-pin of whatever you attach it to (in my case an Arduino Uno R3).

A SparkFun Plug The full project

The end result? Well it is hard to see here, especially since it is just a picture, and not an animation... but I have animated Blinky to wobble in from the right, wait for 5 seconds, and then wobble out the left side of the screen. This makes for a pretty decent ~10 second clip.

A look at Blinky

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