Arduino driving 8 8x8 LED Matrix displays?

Hello all,

I am attempting to make a semi-replica Daft Punk suit for my Grade 11 fancy-dress social/formal thing.

I have a mate involved, and after a bit of a brainstorm, we decided on Daft Punk, with lots of EL wire, and some sort of LED Matrix display’s. We then found this AMAZING instructable on a similar project (extreme Kudo’s to the two of them).

I admire what he has done with the matrix on the helmet, however, me living up to my reputation, I am going overboard.

I purchased 12 8x8 Red Common Cathode 3mm LED Matrix display’s, along with 20 MAX7219 chip’s. EL Wire is to be ordered tomorrow (all 40M of it… :S).

BUT… I was wondering… he has a single matrix display, and after my (very brief) searching, I have only seen people that have extended them lengthwise, I.E daisychained (16x8, 24x8, etc).

I was wondering if it was possible to extend both directions, so that, ideally, I can have a 16x32 display, driven off a duemilanove.

I just fear that if I attempt to scroll text, it is going to scroll on the top line, then go from the top right to bottom left, then off the bottom right.

I have been reading up on the LedControl.h library page, but I just cannot seem to find anything that will confirm or deny this! Can any of you Arduino god’s out there be kind enough to shed some light on this topic?

Thanks in advance.

Woops, sorry, forgot to add link.


yes you can arrange your matrix any way you want weather a library exist or not is a whole different matter, and will somewhat depend on your construction

I was wondering if it was possible to extend both directions, so that, ideally, I can have a 16x32 display, driven off a duemilanove.

There might be a mis-conception here. Each displays (here: 8x8 matrix) is connected to a specific 7221 driver. The data line is cleverly daisychained between those drivers (you will send N*16 bits and each driver will keep 16 for itself, similar as you do it when handouts are distributed in a course :-) But the drivers are not aware of any topology,

This concept is also used in those - hard to find! - "intelligent" LED strips...

Hmm, very interesting...

I had an idea earlier, instead of trying to make it one big string, i will have 2 "banks" of 4 7219's. And instead of, say having the letter A being made for a single digit, I will make it in two parts, A(top) and A(bot), for example. Then, i will scroll the top and bottom half across at the same time.

Can anyone see any issues with that? Or am I overseeing something?


Sorry, sort of skipped your reply there DeSilvia,

So, basically, you are saying that the chip's do not know their topology, as in where and how they are laid out, just that they get the right data? If so, then my previous post may just work...

I will keep you posted.