Multiplex 30 outputs from arduino to control RGB LEDs?

Does anyone have any recommendations for a chip (not SMD please!) that can multiplex a few arduino outputs to pwm 10 RGB LEDs? Also, where can I buy the chip in the UK?

The most popular chip is the TLC5940, you can control 16 outputs with one. So for 30 you would need two of these. They string together very well and there is a library to drive them.
You can get them from any of the usual suspects, Farnell and RS and perhaps even Rapid along with a number of small arduino distributors and resellers.

Thanks very much, sounds perfect. I'm sure I've heard of them somewhere. Are they the chips used in the RGB LED table project? Or are they just a popular chip?

Are they the chips used in the RGB LED table project

Don't know.

are they just a popular chip

Yes.

The 112 rgb table uses these chips.
http://arduino.cc/forum/index.php/topic,8664.0.html

Here is more info.
http://www.arduino.cc/playground/Learning/TLC5940

Best of luck

Sorry about the thread resurrection, but I didn't realise that TLC5940s sink current. Something I found out after I bought two... Anyway, do you know of a chip that can source current to control the 30 outputs, and is controlled via serial or I2C or something that doesn't use every pin on my arduino!

Thanks,
Singul4r1ty

Put an inverter on the TLC5940 outputs.
If you read its datasheet, I believe it says it needs to sink at least 5mA to work - so add 820ohm pullup resisters to the outputs, set the current limit to 5mA via software, and add an inverter/driver chip to source the current.
SN74AC240N, can source 24mA

Add current limit resisters as needed for your particular LEDs/color.

Is it not easier to buy a different IC? I'd prefer not to have to connect multiple ICs when there is probably a simpler solution. Thanks for the suggestion, though.

Singul4r1ty.

Simpler solution would be to buy common anode LEDs.

I might be going out on a limb here, but what about using a 74HC595 shift register chip setup?

I just started using several outputs, and it amazes me how easy the shift register is to set up and use, and once I need more outputs, I just connect one more to the previous one, and it doesn't need more outputs from the microcontroller.

You just need 3 digital outputs and you can chain like 40+ together, 8 output each.

but what about using a 74HC595 shift register chip setup?

Because you can't control the brightness it is just on or off. So with an RGB LED you only have 7 possible colours.

And the 74HC595 is not good for high current either. The 74AC240 can put out 20mA no sweat. The 595 only good for 6-8mA.

So what does the 74AC240 do? Is it an inverter chip?

It is a buffer chip, it gives you more current.
http://www.google.co.uk/url?sa=t&source=web&cd=1&ved=0CBcQFjAA&url=http%3A%2F%2Fwww.fairchildsemi.com%2Fds%2F74%2F74AC240.pdf&ei=KTMrTqDyJorMhAf-_8GqCw&usg=AFQjCNHYD8ZxnmC15UXaVoAynVY5FFs5PQ&sig2=E1PMo4EI7veoq945V807nw