5x7 LED Matrix Blinkie Kit

This is a 5x7 LED Matrix Blinkie Kit. Its a 1.8 by 2.95 double-sided circuit circuit board with a mounting pin on the back side, that requires assembly and soldering. Patterns and text scroll on a matrix made up of 35 leds, which can be single-color or bi-colored depending on the fireware. Yes, there is an IR emitter and receiver for two way communication to other blinkie boards. This blinkie design was introduced at Duckon 15

Check out:

http://www.2dkits.com/

A lot of LEDs from a few microcontroller pins

Using the fact that many microcontroller pins have three states (+V, GND, or "high impedence", you can drive N*(N-1) LEDs from N pins. So the little 8 pin microcontroller like a PIC12Fxxx or an ATtiny11 can drive 20 LEDs on its five available output pins, and still have one pin left for so me kind of input.

http://www.instructables.com/id/ED0NCY0UVWEP287ISO/