32x32

-Programmer tries hardware.

How would you suggest connecting the arduino to a 32x32 led matrix?

-This means independent control of 1024 LEDs.

( How do I power them? Do I need to if I use a multiplexer?)

Should I use the MAX7219 or the 595. Can someone identify the main difference? Pros\cons with each?

I'm also a little concerned in the memorycapacity on the Arduino, is there a way to add some memory? (think this scetch will become large)

Use 16 MAX7219's (I think). They multiplex so at any one time only 1 LED per chip is on. It makes it use less power.

As for program size, I believe the ATmega168 keeps program memory separate to the data memory so unfortunately you cant do any really cool tricks to increase capacity. The best way is to make your Arduino dumb and make a computer do all the hard work.

I have actually decided for 595, because I believe it would've been to much delay changing all 1024 LEDs, this is not a static display.

But, how do I power them? Still a n00b at electronics, so if someone could show me some easy understandable charts, or even better: images of the real deal, I would've been most thankful.

How many 595's are you using?

Well.

32x32 becomes 1024 and a 595 can control 8 LEDs, that becomes 128 à 595. One hell of a mess as well ::)

I hope I'm wrong, or that there is another way of doing it, but equally "hardcore" 8-). Do not want a premade matrix, that's booring.

Looking forward to this.

I hope I'm wrong, or that there is another way of doing it, but equally "hardcore" 8-). Do not want a premade matrix, that's booring.

I'm planning something similar. 8x8 but with RGB LEDs. I might do 32x32 RGB afterwards. ;D

If I were you, I'd use multiple processors. Maybe one per 16x16 block which means 4 processors plus one to control them. I doubt one ATmega168 could give a decent refresh rate with 1024 leds.

Sounds like a great idea, but I have no clue how to do it. How to get the arduino to control four other processors...

Hmm, this sounds very interesting indeed.

The refresh rate will be fine, using 595's and you won't need to worry about alternative power source, the LED's will power straight off the board.

I've got stacks of them here but no time to wire them all up, they do incredible things though, and very simple to setup - a little bit of a mess but you could draw custom boards that might tidy things up a little.

Make sure you post pic's as you go :)

Do you think the Arduino can handle almost 1000 LEDs at any one time?

Hmm.

It's not the quantity that is relevant, remember with the 595's only one pin's on at a time in very quick succession, 1,000's completely doo'able

It's not the quantity that is relevant, remember with the 595's only one pin's on at a time in very quick succession, 1,000's completely doo'able

I think your mixing up the 74HC595 with the MAX7219/21. :P The 595 doesnt multiplex so every single LED is on all the time. And if AlphaBeta wants animation at a decent FPS, one Arduino probably wont cut it.

AlphaBeta can you give us more information about the setup you were wanting? E.g. computer controlled or standalone, what fps is desired, etc...

Oh btw with that many LEDs you will need a good power supply. Your looking at 20.5 amps. Time to find a old computer power supply to modify. ;)

I forgot. This is supposed to become a wallmounted picture, rather than a screen. So preferred fps? 1 would do ;)

(Some alterning between images, but not fast animations)

Anyways, I am very interrested in the 'adding processors' idea.

And when I find a power supply, how do I hook it up to the LEDs? (And for my later projects, how did you calculate the amps?)

Summary: 1* I wonder how to extend the processing capabilities, more than happy to see some easy-understandeable diagrams. 2* How to power LEDs?

It's not the quantity that is relevant, remember with the 595's only one pin's on at a time in very quick succession, 1,000's completely doo'able

I think your mixing up the 74HC595 with the MAX7219/21. :P

Nope, the pile of chips I've got here definitely say "74HC595"

I've only spent 2 months working with them, and hundreds of mcd10,000 LEDs & stacks of relays piled on top of the LEDs - and just the arduino, no external power source.

So maybe I've got a feaky arduino, you think?

The 595 doesnt multiplex so every single LED is on all the time.
)

erm - the 595 is a multiplexer, 3 inputs - 8 outputs. :wink:

So maybe I've got a feaky arduino, you think?

You've been powering the equivalent of 1000 leds off a single usb port? Thats more along the lines of a freaky usb port. They usually only provide 100 - 200mA with the maximum being 500mA.

erm - the 595 is a multiplexer, 3 inputs - 8 outputs. ;)

Well technically one input, a clock and a latch. :P

Am I using the right M word? I forget. The point is the 595 keeps all the LEDs on at the same time while the 7219/21 switches them on and off rapidly since they are arranged in a grid.

So maybe I've got a feaky arduino, you think?

You've been powering the equivalent of 1000 leds off a single usb port? Thats more along the lines of a freaky usb port. They usually only provide 100 - 200mA with the maximum being 500mA.

erm - the 595 is a multiplexer, 3 inputs - 8 outputs. ;)

Well technically one input, a clock and a latch. :P

Am I using the right M word? I forget. The point is the 595 keeps all the LEDs on at the same time while the 7219/21 switches them on and off rapidly since they are arranged in a grid.

3 to 8, that's a multiplexer by any definition.

No, they get switched on and off in quick succession.

I had 5 595's wired up but have been ripping things apart for another project, right now I've got 3 595's, 24 x 10,000 mcd LED's, and 5 relays stacked on top of 5 LED's - the LED's alone, by your definition, are drawing 600mA - which isn't possible, right?

5 595's and 40 LED's is as bright as 3 595's and 24 LED's, so I must have a freaky Arduino - I'll post a video of the set up and a close up of the board, it's an off-the-shelf NG :)

oh yeah, here's the first two I posted a while back, they were standard green's - I promoted those to the high bright and bought 10 extra 595's from a local electronic's shop.

Added into that, is a parallax RFID reader - so that's 3 595's & 24 10,000's, 1 x 7021 with 8 input switches, 1 parallax RFID reader, and 5 relays - not bad for a 500mA micro :)

I was under the impression that only the MAX7219 flashes on and off, in a rapid succession. An as for the 595, leaves the LEDs on or off until changed.

And I do agree thet they both multiplex. I assume any object that allows different signals, to different outs, in same conductor is a multiplexer? -but hvat do I know?

?

Anyways, how do I connect Power?

Its the 595 that does that, or I've got a mutant board.

Here's a tutorial for the 595

http://www.arduino.cc/en/Tutorial/ShiftOut

Connect power? - to the LEDs or the board?

Here's the rig at the moment, the last 595 board is connected using a reasonably heavy duty extension cable, and has LED's riding over the top of the relays.

To the right is the parallax (with a coil extension).

Center top is the "CD4021B" (not 7071) with 8 switches.

At the bottom, the two original 595's with 10,000 mcd's rather than the standard greens from the first pic.

And that is all I require for my current project.

I do have another smaller BB with a 595 and 8 more LEDs wired, when I get a moment I'll add that in and post an updated pic - with it plugged in and creating such an intense light field, it's almost impossible to look at directly.

I've seen that tut, but thanks anyways.

How to connect power to the LEDs, or can I connect power direct to the Arduino? (Does not sound like a thing I dare, 20+ A is quite alot.)