Howdy,
I just finished building the Open Heart kit by Jimmie Rodgers:
http://jimmieprodgers.com/kits/openheart/
Charlieplexing is cleverly applied so that 27 LEDs are driven by just 6 pins. The heart-shaped LED matrix could be used with any microcontroller platform. For those partial to Arduino, Jimmie offers source code for displaying patterns. I easily hooked up the Open Heart to an Arduino-clone from Adafruit, the DC Boarduino:
In the source code download, there is also a nifty web-based graphical editor which allows easy creation of new patterns and animations:
Here's a quick video of my Open Heart running the default animations in the example sketch:
The video captures some of the unintended LED illumination during a couple animations. I believe this is just a consequence of charlieplexing, and it is not very noticeable to the naked eye.
With Valentinie's Day approaching, I think this easy and inexpensive kit has the potential to make a nice gift. Check out Make's article on making an Open Heart headband that shows the wearer's actual heartbeat:
http://makeprojects.com/Project/Beating-Heart-Headband/1622/1
Cheers,
Drew
