CharliePlexed RGB LED Dice
Electronic dice persay is not a very interesting electronic project, but controlling 21 LEDs with just 4 I/O microcontroller pins is really interesting. Multiplexing used in this project is Charlieplexing. We all know that electronic dice requires just 7 LEDs, but since RGB LEDs were used, a total of 21 LEDs had to be controlled.
After a pushbutton is pressed, microcontroller ATtiny13V generates a random number from 1 to 6 and displays the result on RGB LEDs in 6 possible collors and in random fashion.
[ Source: cedtlab ]