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Bi-color LED on prop1

Started by RobertB, May 02, 2010, 05:51:53 PM

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RobertB

Jon,

Regarding the bi-color LED post of October 2009, I'm still lost.

I want to use a bi-color LED simply to indicate if a trigger event has occurred.

I have a red/green LED wired up with a 470 ohm resistor to use on the 12v output terminals 4 and 5. 
How do I wire the thing up?  Should I use the 12V outputs at all? 

My test code is adapted from the "What's a Microcontroller" book page 61 (written for a prop2):
Main:

HIGH 4           'send the current one way
LOW 5
PAUSE 1000

HIGH 5            'send the current the other way
LOW 4
PAUSE 1000

GOTO Main

-Thank for any help you can give me. 

JonnyMac

You cannot use the 12v outputs for bi-color LEDs.  The reason is that you need one pin to "push" (be positive) and the other to "pull" (be negative).  This means you'll need to use two of the 5v Px.W outputs.  When one is HIGH and the other LOW the LED will be lit; when both are at the same level it will be off.
Jon McPhalen
EFX-TEK Hollywood Office

RobertB

That's the conclusion I was coming to. 

Just wanted to ask before I tore apart the LED circuit I built.

Thanks Jon.

JonnyMac

I don't know that I've ever seen them, but if you had a 3-lead, common-anode LED then you could use the OUTx terminals.  If you happen to come across such a beast make sure you use a current-limiter in both circuits as both could be on at the same time.
Jon McPhalen
EFX-TEK Hollywood Office

JackMan

Another simple option is to just use two normal LED's of different color if you have room on your board.

RobertB

So, using a TWO conductor, bi-color LED, throw a 100 ohm restistor on the positive lead, split the positive lead, and connect like:
as in the diagram from http://www.efx-tek.com/php/smf/index.php?topic=1299.0

I don't see how this would work.

RobertB

Never mind, I got it working.  Put a 100ohm resistor in the loop and connected the LED between p4 White and p5 White.

Deathtouch

I actually am doing that for my fcg.  I am using a relay to switch it.  It works pretty good.