All jazzed up on coffee and its Friday night.

Has anyone come up with a way to set up two Peggy2's side by side and passed info from the first Peggy on to the to the second?

Like a 25x50 Peggy2x2?

It *can* be done that way, but it's probably easier to stream data from a single source to multiple Peggy boards. Here's one example:

http://hackaday.com/2009/12/19/peggy2-x2-with-video/

If you really do want to control 25 x 50 from one controller, you could either send data between the two over serial or over I2C.

Another way would be to actually remove the microcontroller from the second board, and just control the 25 x 50 array directly with one chip: daisy chain the LED driver chips over SPI, and wire the same eight signals that control the row selection to the other board as well. Then, just shift out eight bytes (not four bytes) for each row of the matrix. Might be a neat trick, actually.

Thanks Windell,

I figured the SPI might work but wasnt sure.

I'll start again and see what I can make of this.

Just wondering why the Transistors are used instead of some ULN2803's on the Rows?

>Just wondering why the Transistors are used instead of some ULN2803's on the Rows

The ULN2803 does not supply enough current to drive a full row of LEDs, and its saturation voltage is way too high-- if you use it (even at the lower voltage that it would allow), you'll get significantly different brightness depending on how many LEDs and of what color are driven. It would be cheaper, but it would be a huge and unacceptable loss in both performance and capability.