For
dorkbotpdx last night, I made this little toy:
It's an 8x8 red+green LED Matrix, driven by two shift registers and a Bare Bones Board Freeduino by
Modern Device Company.
Before the meeting I just had it flashing fun patterns based on odd bit-math equations. During the meeting, I was urged to add some code to make it controllable by the Wii Nunchuk. So, I wrote a simple program that takes the X and Y of accelerometer and plots it on the matrix.
I drove the LED Matrix with three shift registers: One 74HC595 8-bit register gave power to the rows of the display, and one Maxim-IC MAX6969 sank current for the columns to the display. To turn on row 1, column one, you shift "B10000000" into the row register, and "B10000000" into the column register:
B 1 0 0 0 0 0 0 0
1 x o o o o o o o
0 o o o o o o o o
0 o o o o o o o o
0 o o o o o o o o
0 o o o o o o o o
0 o o o o o o o o
0 o o o o o o o o
0 o o o o o o o o
Altogether, it was about 30 lines of code to drive the matrix with some fun patterns.
Also seen at:
my blog