[Lab] how to control several RGB LEDs with Arduino

[Jaime Yu]

Hey,

Try Charlieplexing (https://en.wikipedia.org/wiki/Charlieplexing &
http://lmgtfy.com/?q=charlieplexing). My brother used this for one of his
projects. Its a pretty neat analog circuit.

You can also multiplex the LEDs to get you a bit more 'outputs', but not as
many as charlieplexing. But it is safer since you're not driving as much
current as charlieplexing.

--
Sincerely,
Jaime Yu
B.Eng in Computer Engineering, System Hardware
Software Developer III at Juniper Networks

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On Fri, Aug 1, 2014 at 8:59 AM, Olaf Baumann <olaf.baumann at pobox.com> wrote:

> Hey Lab,
>
> I got some RGB LEDS to play with but when I count the number of pins I
> need, it doesn't look like I can drive very many.
>
> The UNO has six PWM output pins and each RGB LED needs three.  As the
> saying goes, twos company, but I want a crowd!
>
> With regular LEDs, I used cascading shift registers to allow me to control
> 24 of them.  A great success in my temporarily blinded eyes.
>
> Is there an analog analogue to the digital shift register?  It seems that
> PWM is a hack for a voltage level, would a steady voltage be better?  SPI
> or I2C would be bonus--maybe I could use an ATtiny85.
>
> thanks,
> Olaf
>
>
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