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Main => Main Forum => Topic started by: coasternuts on January 29, 2007, 11:07:24 am

Title: Run LED's off of +5V on Opti-wiz?
Post by: coasternuts on January 29, 2007, 11:07:24 am
Is this possible or is that going to cause problems with the Opti-wiz?

Is it possible with only a couple, if several will cause problems?

The reason I'm asking is that I have one button that I'm lighting up on one panel,
and 4 on another panel.

Thanks.
Title: Re: Run LED's off of +5V on Opti-wiz?
Post by: ChadTower on January 29, 2007, 11:13:16 am

1 and 4 shouldn't cause any problem at all. They draw practically zero current.  Now, if you wanted to add 25, maybe, but that few should not be an issue.

Note that does not apply to light bulbs, just LEDs.
Title: Re: Run LED's off of +5V on Opti-wiz?
Post by: Buddabing on January 29, 2007, 12:33:14 pm
Four LEDs may not work if they are wired in series. Depending on the LED, the voltage drop across each LED is approximately two volts.

Also, you should ask Randy how much current can be drawn. LEDs require roughly 20 milliamps, give or take. I'm guessing this will not be a problem.

I don't think it would break anything if you tried wiring it up, the LEDs should just dim or not work at all if the voltage or current is insufficient.

Don't forget a small resistor in your circuit to protect your LED(s). Not having a resistor may destroy your LED.
Title: Re: Run LED's off of +5V on Opti-wiz?
Post by: ChadTower on January 29, 2007, 12:35:10 pm
Four LEDs may not work if they are wired in series. Depending on the LED, the voltage drop across each LED is approximately two volts.

I did assume he was going to wire in parallel in my answer.  Good to point this out.
Title: Re: Run LED's off of +5V on Opti-wiz?
Post by: ultrageek on January 29, 2007, 02:06:16 pm
I have done exactly this and it seems to work ok.  I hooked the LedWiz to the +5V from the OptiPac and hooked 2 Led's up in series to the first 2 ports on the Wiz. NO JOY!
Changed the hookups to parallel and they glow like..well... things that glow! ;)
I did put a 15 ohm resistor in line with each Led.
Now, if I could just find a good way to control them...
-Lee
Title: Re: Run LED's off of +5V on Opti-wiz?
Post by: coasternuts on January 29, 2007, 02:09:59 pm
Excellent.  I have one panel which will only have two, so I figured that would probably work.

But the other panel I intend to do 4 buttons (2 LED each) in this configuration.

http://led.linear1.org/led.wiz?VS=5&VF=1.9&ID=20&N=8

My concern was that it would interfere with the Opti-wiz operation.

Thanks for the info.
Title: Re: Run LED's off of +5V on Opti-wiz?
Post by: RandyT on January 30, 2007, 06:19:57 pm

My thoughts on this one are as long as you don't pull more current through the USB / PS/2 port than it it is able to deliver, you should be fine.

With non-powered USB ports, this is up to 500 ma (before any devices are factored in.)

So I don't see any problems with 2, 4 or 8 LED's being powered from the 5v line on the interface, unless you have an LED-Wiz on the same port with a bunch of LEDs being powered by it.

As mentioned before, make sure you use the correct resistors for your LEDs or else LEDs = junk  :)

RandyT