Controlling 105 RGB leds with arduino?

well, i got an arduino... and i saw the post for the led table... i would like to make one, with 105 rgb leds... how can i control it with one arduino duemilanove

First you would go through the post about the 112 led table real well and get an idea of how it was made and programmed.

Then you would make the same thing with 15 columns instead of 16.

Hope that helps. ;)

What sort of LEDs, single colour or RGB? Do you want to be able to dim the LEDs? If so signally or in groups?

I would recommend relegating the actual multiplexing to a hardware chip like the MAX6954. That can handle up to 128 LEDs and dim them in groups of 16.

im using 105 common negative rgb leds... a total of 315 leds in theory... i want all controlled by one atmega328... I have no idea where to start... how do i program an atmega328 with arduino enviornment... not an arduino, but just the chip... can i do it with an arduino mini adapter? this: and this:

im using 105 common negative rgb leds

If you haven't bought them yet, you should really consider getting common anode: most of the low-cost solutions are designed for them.

a total of 315 leds in theory

In practice too. ;)

not an arduino, but just the chip... can i do it with an arduino mini adapter?

Yes, basically you need some sort of header that you can put your TTL level serial signals into. Also put a capacitor between the DTR and the reset line and pull the reset line to +5 through 10K.

yeah, im going to get common annodes, but i still need to control it

i have figured out that i can use tlc5940's... can they be used for negatives as well?

can they be used for negatives as well?

Not directly (assuming that by "negatives" you mean "common cathode"): the TLC5940 has current-sinking outputs. You'd need to use those to control high-side drivers to power common-cathode LEDs. It's do-able, but wasteful.

how should i do it? i want to do rows and colums... i forget the term... anyways, common annode or cathode? and what chips?

i made my own LED matrix 8x6 and i bought 500 ultra bright blue leds it dose not matter the type just as long as there all the same. that would be the easiest way to make the led matrix of any kind and of any size i went through about 10 to 20 be fore i got the soldering and board configuration down. once you have the led matrix of awesome size then its up to code im using the arduino mega and just 14 digital pins i can make it do just amazing things its really fun and i plan on going large scale and making a hole 6' x 7' wall of RBG LEDS. use the max chip that uses serial of just 4 pins and can connect manny other max chips in a line to carry the info to one after the other to the other so only 4 pins and one arduino and a lot of max chips would work.

hmm... if you think about it, i will need 4 tlc5940's... how do i hook them all up to one arduino?

i will need 4 tlc5940's

More like 20. Or 21, since you'll probably find it convenient to group the LEDs into equal-sized subassemblies.

Since the TLC5490 is much like a shift register with attached logic and drivers, you can daisy-chain them just like the 74HC595s used in many of the examples in the Playground and the forums.

thats what i origionally thought... are you saying i should control every pin of every led? i was thinking of the rows and colums thing...

are you saying i should control every pin of every led?

Yeah, but I could be wrong: I figured the high volume of data (12 bits per LED) would rule out multiplexing with TLC5940s, but I see that there's an experimental version of the library intended to allow it.

It's not clear how much you can mux, though: you need to get some advice from someone with experience doing it to determine that.

i was thinking of the rows and colums thing.

You can multiplex the TLC9540 chip with a bit of software, look at this project:- But you loose brightness and I wouldn't go any more than a four row multiplex.

first of all, ut lucky! i want a mac... anyways...

its stupid to lose bightness on high brightness leds... so i guess ill wire each, and try to organise the rats mess

does anybody know anything cheaper that a tlc5940, because theyre like 4 bucks each, and that $80 before shipping...