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Topic: big multiplexing tri colour led cube - will it refresh fast enough ? (Read 3 times) previous topic - next topic


doh!  I was hoping for something I could clip the chip into, which would then happily solder into a perf board....

guess I might have to look at using different chips then :o


Jan 23, 2012, 06:37 pm Last Edit: Jan 23, 2012, 06:39 pm by evanrich Reason: 1

doh... typed out a reply.... had an idea... went to google it... lost my reply :-(

Way off topic, but if you use firefox for your browser, stop what you're doing and go grab a plugin/addon called "Lazarus: Form Recovery".   I cannot tell you how many times I've been writing an email, filling out a form, posting a VERY LONG forum reply, just to have the site act up, my internet go out, get logged out.. whatever...just to find that when I can get back to the page, all my typing is gone.

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My first major project (looking for people who would like to help contribute) Bluetooth Sure 32x16 LED Displays!: https://github.com/evanric


Jan 08, 2013, 09:41 pm Last Edit: Jan 08, 2013, 09:43 pm by Ruffsta Reason: 1
@knighty.. you were right at saying bi-color if yer only using 2 colors..

and i thought my 400 tri color led multiplexing was a huge project..

i can't seem to the exact answers to multiplex 100 tri color leds at a time that i seek.. and you want to do 13k of them?

knighty, good luck with it.. would like to see how it comes out when yer done with it!


Jan 08, 2013, 09:49 pm Last Edit: Jan 09, 2013, 03:23 pm by CrossRoads Reason: 1
Well, knighty hasn't posted to the forum since
February 04, 2012, 03:54:59 PM
would not hold my breath waiting for a reply!

Its certainly possible to do more complex things, but likely more processing power is needed:
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.


I'm planning to build a really big tri colour led cube but I'm worried with so many LEDs the multiplexing will be too slow

if I use a TLC5951DAP as an led driver it will give me 24 outputs with 12 bit resolution for brightness control

I'm thinking of building a 24x24x24 cube (13,000 led's)

24x24x24 RGB LEDs is actually 41472 LEDs (24x24x24x3)

Whichever way you slice it, that's a lot of LEDs ... and a lot of input data.

It's definitely not going to work by updating LEDs individually.

Even if you only update one row of LEDs at a time you need to update it a 50kHz to get a usable frame rate (24x24x100) - simply not going to happen with an Arduino Uno at 16MHz.

The only way I can see it working is to divide it up into planes and have each plane controlled by a separate processor. That divides all your numbers by 24 and makes them sensible.

Each plane could be multiplexed in rows so your multiplexing ratio is 24:1. Each row has 72 LEDs so it could be driven with 5xTLC5940 (or whatever...), perfectly possible to do with an Arduino-class chip.

Physically supporting the LEDs as separate planes would be tricky. I suppose that's why most big cubes I've seen seem to be hung on wires - make gravity work for you, not against you.

No, I don't answer questions sent in private messages (but I do accept thank-you notes...)

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