[Robotgroup] Bicolor LED help

[Evan Harris]

There are more than one type of bicolor LED's.

If they have two leads, they are bipolar LEDs, meaning you have to drive 
them with current flow in one direction or the other to light the 
appropriate color, and only one color can be lit at a time.  (Though you can 
do persistence of vision tricks by switching back and forth very quickly to 
make it appear that they are both lit).

If they have three leads, then one lead is a common (either anode or
cathode), and the other leads can be used to individually control the
distinct colors, and both (or more for multicolor LEDs) can be driven at the
same time.

Most microcontrollers can only drive unipolar LED's, unless they have a
specialized bipolar driver of some sort, or you do other electrical tricks.

Evan

On Thu, 7 Dec 2006, Mohammad El-Abid wrote:

> Hello I just bought a bicolor green/red LED for my boe-bot and I thought
> their was a command to reverse the current somehow, but I think I must've
> been confused with the reverse method. Anyway can anyone help me with
> setting up a bicolor LED? I can go on one color just not the other.
>
>
>
> Thanks in advance,
>
> Mohammad.
>
> _______________________________________________
> Robotgroup mailing list
> Robotgroup at puremagic.com
> http://lists.puremagic.com/cgi-bin/mailman/listinfo/robotgroup
>