Hello,
I have the Arduino duemilanove.
What I want to create is 16 RGB led bars and I want them to randomaly pulse to different colours.
Could I connect the colours (i.E red) to a seprate board and then connect that board to the arduino, I only would only use 4 pins.
I don't want to change indiviual colours, I only want to controll all of them at the same brightness and the same time to pulse.
I am a complete beginner so please any comments would be welcome. :-[
I think the Arduino might not be able to source the current required. So you might have to use a transistor/driver circuit which will be driven by the arduino. You would need to make some calculations on the current required to drive the leds by looking at their datasheet and choose a suitable transistor/driver circuitry accordingly.
Cheers,
Prakash
Take a look here for some inspiration:
Thanks,
I did see that site before MikMo, but he does it with a knob to change
colours as I want to do it by itself. No worries that's programming.
My issue was have these 16 bar/strips that have 8RGB LEDS per strip connect. I can get a different power source I'm just wondering when I connect the Bars do I make other circuits.
For example when all the bars come to connect I have all the Red connecting together(and the blue with the blue and so on...) Then have
the red connected with a Pin to the arduino.
Which should use only 4 pins.
Is that correct?
Can I do this?
Or does it even make sense :-?.
lol
So if i understand it correct, you have 16 bars, each with 8 RGB LED's and you want to control all The R's G's and B's together so all 8 bars would have the same color at any given time ?
If that is the case you could do as the link above, but of course expand the wiring so all the "R terminals" on the 8 bars are connected togetger to one suitable transistor, the same with the G's and the B's. Each ransistor could be driven by one PWM pin on Arduino.
The IC he is using is basically just 7 Darlington transistors (he is using only 3). But in your setup you will probably need something that can handle more current than the 2003 IC he is using.
You should calculate how much current all the red LED's will ned, and find a transistor that can handle it. same thing for green and blue.
You should also figure out if your LED bars have built in current limiting resistors or not. If not you need to add them.
I would start with a setup controlling just one LED bar, figure everything out, and then add the other seven.
Thank you, ;D
That's the kind of answer I was looking for.
I haven't made the LED bars yet, but I will have resistors within them.
I will add the curents up and see where I can go.
If I can get them go at the same time then I can use it for lighting my room, should look good. 
It's almost like this:
Mine is brighter and I want them to act the same.
;D You get the picture.
You should seriously consider the RGB LED strips from Dealextreme, you cen get them in lengths up to 5m (around 15 feet) that can be cut into smaller sections, they are reasonably cheap, and come with free world wide shipping. they have the resistors built in and are easy to control with Arduino.
Seems good.
I think I would still have to attach them to transitors?
The Leds I've got are a lot brighter.
One LED lights up half my room. 
One LED lights up half my room
If you have high power LEDs then it is not sufficient to just use a transistor and resistor to control them. You need a constant current supply.
In fact here are the LEDs I got,
http://cgi.ebay.co.uk/10X-PIRANHA-RGB-5mm-LED-Lamp-8Kmcd-COMMON-ANODE-/290385238470?cmd=ViewItem&pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item439c4f19c6
Also it came with it's own resitors
Ok these are not high power LEDs so you are fine with just using resistors.
Ok,
I found this.
He uses the same LEDS as mine. I don't want mine to react with the music. Only to randomaly cycle through colours in a slow and calm manor ;D