SparkFun Forums

[Lefty4000]

Hello,

I need a microprocessor that can handle sending out information to several microcontollers.
Basically I need to be able to individually control over 11000 RGB LEDs. For a scrolling message to work i'd have the microprocessor figure the display and send a basic amount of info to a microcontroller that would handle the distribution of the signal to the correct leds that is in a 12x12 matrix. I need about 80 of these boards to cover a 10x8 foot area on the wall. Any ideas?

I would love to have this on SFE considering everything else I need is there.

[lyndon]

SPI, TWI, I2C, RS232

Lots of ways for standard microcontrollers to communicate.

[Mee_n_Mac]

Any ideas?

Yes but probably not a good one !

Instead of using 80 of your matrix boards, you could use 180 of these (or really just the backpack portion) and arrange them in a 15 x 12 matrix, where each backpack controls an 8x8 set of RGB LEDs (as opposed to your 12x12 set). I believe each backpack can be daisychained though I've not bother to work out what the timing would be to update 180 of them. You might have to divide that task up. Of course the cost in now at least 2X what it could be if you had a 12x12 controller ... but you did ask for any ideas.

FWIW I doubt enough of your 12x12 matrices would be sold to justify the investment by SF. But that needn't stop you from mutating the design above into what you need.

[Lefty4000]

I'm not exactly looking for a communication, I can figure out the comm out, its the microcontroller i need to figure out. I need one that can handle that kind of load.

[leon_heller]

XMOS devices are used for large LED displays:

http://www.xmos.com/applications/led-signs-and-displays

[lyndon]

Doesn't seem that hard to do it with a single MCU and a bunch of shift registers.

You want to control 80 12x12 matrices of LEDs. If you use two 8-bit shift registers each for row & column addressing on each board, and two 8-channel source and sink drivers on on the rows & columns, that's only a total of
80 x 32 = 2560 bits for each update. If you are using high efficiency LEDs you may not even need the drivers.

Assuming you update all the LEDs at a 24Hz rate to avoid flicker, then that's 24x2560 = 61.4kHz update rate. You can bit bang that with a 1MHz microcontroller. A 75Hz rate would be even better and it's still doable in software. I'd consider using a synchronous serial output to avoid having to bit-bang, but that's an implementation detail.

[edit]
corrected my math.

[Lefty4000]

what is bit bang?

[skimask]

Manually toggling bits...i.e. doing serial communications by twiddling bits high and low and calculating the timing "manually" vs. using a built in UART module.
http://en.wikipedia.org/wiki/Bit_banging
Amazing...

[Lefty4000]

Oh, I think tahts all I know how to do. haha