Need led matrix help

Ok first off I am real green :grin: when it comes to most of this so please bear with me. What Im doing is building a costume head that has two 4.5" eye lenses that I would like to back with an led matrix ( preferably a 16x16 or if anyone knows how I would rather have a round matrix if its possible) and run through a series of images, for example I might tie each sequence to a button and once pressed it would make the eyes light up with an "X" pattern and the next button would change it to a pac-man shape on one eye and ghost on the other etc... so basically I need to store and run a few different led sequences tied to a trigger of some sort on an rgb matrix (round if possible) sorry in advance and I would appreciate any input thanks

Are you looking to buy or make? If you want a round matrix then I guess you will have to make it, I have never seen one of these. There are lots of examples in the playground, but beware of he example with no resistors or any other form of current limiting, that one is an arduino killer.

I have no problem making something if I have to, I just need some guidance, if a round is possible thats what Im gonna lean towards, and I guess after that the rest is in programming?

You could wire up 256 LEDs to 4 MAX7221 and arrange them however you'd like on your costume, then send pattern info as 8 SPI.transfers to each of the MAX7221s. Or make your own equivalent be making a matrix with Arduino driving 16 rows of anodes, and part like TPIC6B595 sinking the 16 cathodes 1 row at a time, and write your own multiplex loop (its not that hard): write anodes, sink a column, write next anodes, sink the column, repeat 14 more times, repeat. Update the anode info occasionally. 16 x 16 is a 256 byte array. Maybe have 2 of them, one being displayed, and being populated per some math you write, so you don't need lots & lots of arrays stored for your patterns.

Ok I follow most of that lol, so what limits how many patterns I can run? or is it limitless? Is programing a pain in the butt? can I use any blank board to mount the leds? again sorry for the noob ?'s but I really appreciate the help guys XD


Using a MAX7221… Interesting… I just download the datasheet. 1 chip can display a 8X8 Matrix. One question ? Where can I buy this part ? I find two e-store requiesting to order more than $250 min. < — kidding me !! no way !! And How much is the chip ? ← MAX7221

A google search turns up several places that carry the max7221 at reasonable prices. Do the search, then click on SHOPPING on the left side. show me a limited location.

Thank kd7eir.