[SOLVED] Need to know what these wires do on this led

AllanGH

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It's likely just an RGB LED.
V+ is the Common Anode connection. (Likely 5VDC....possibly 3.3VDC)
B is Blue Cathode connection (through a current limiting resistor)
G is Green Cathode connection (through a current limiting resistor)
R is Red Cathode connection (through a current limiting resistor)

DET appears to be a "Detect" input...."RX" would refer to a receiver signal of some type.

What is this a part of?
 
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zachholtzclaw

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It's likely just an RGB LED.
V+ is the Common Anode connection. (Likely 5VDC....possibly 3.3VDC)
B is Blue Cathode connection (through a current limiting resistor)
G is Green Cathode connection (through a current limiting resistor)
R is Red Cathode connection (through a current limiting resistor)

DET appears to be a "Detect" input...."RX" would refer to a receiver signal of some type.

What is this a part of?
Alien head led from my old alienware x51 r2
Is there a way to rewire the led plug to work with something on my motherboard.
http://download.gigabyte.us/FileList/Manual/mb_manual_ga-ax370-gaming5_e.pdf
 

AllanGH

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You could likely use it on a 5V RGB header, if you have one present on your MB. Unless you test it with a safe source of +12VDC, and find that it's fine at that voltage, I wouldn't dare pop it on a 12V RGB header. Of course, you'd probably have to cut-off the "DET" wire, and re-terminal the connector end to get it to mate properly with any RGB header you might have.

The principal of operation is identical to the 5050 RGB strip lighting that you see around (not ARGBs, mind you), but it has a single RGB element instead of many RGB elements.
 

AllanGH

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Test it with 12VDC, and if it survives....LOL....you could use it on the LED_C1 header. You'll just have to crimp some "Dupont" terminals on the wire ends, and load up a 4-position connector block in the proper order.
 

Karadjgne

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There's 3x lighting zones in Alienware x51 . Left panel, right panel and the Head on the front. That header is the one that goes to the Head logo and its light up eyes. My guess would be that it's a low side, common anode rgb with pwm to control pulse and other affects. Most likely it's 12v, most pwm is, but considering it's Dell, it's proprietary, so there's actually no telling. So the pins are likely B, G, R, pwm signal, V+
 

AllanGH

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Now that I think about what you've said, one could do the PWM as low-side switching on the R, G, and B cathode leads, with the DET wire serving as detection for the presence of the module on the header, or as PWM feedback for the driver.

Still, I'd like to know the value of at least the resistor in the red cathode circuit, as that would give a good idea of the design voltage.
 

Karadjgne

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Yeah, normally rgb switching is high side with a ground as 4th lead, but with V+, I'm thinking low side, which is better for control anyways. As far as resistors go, since it's not on a strip, but a measly 2x eyeball logo head, that's probably going to be stuck on the front side of that panel, connected to D11, unless D11 IS variable resistance controlled by the pwm signal coming from the Alien FX software. Hard to say, Dell always did do funky stuff, all in the name of brand protection. Is Proprietaryanism a word?
 

zachholtzclaw

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Now that I think about what you've said, one could do the PWM as low-side switching on the R, G, and B cathode leads, with the DET wire serving as detection for the presence of the module on the header, or as PWM feedback for the driver.

Still, I'd like to know the value of at least the resistor in the red cathode circuit, as that would give a good idea of the design voltage.
Test it with 12VDC, and if it survives....LOL....you could use it on the LED_C1 header. You'll just have to crimp some "Dupont" terminals on the wire ends, and load up a 4-position connector block in the proper order.
my mb only has 12v could i solder a resistor to voltage wire to drop it from 12v to 5v?
 

AllanGH

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my mb only has 12v could i solder a resistor to voltage wire to drop it from 12v to 5v?
You'd actually need to add current limiting resistors to each of the R, G, and B wires, instead of a single resistor to the V+ wire; and the resistors that are already there are probably low-balled for PWM, so we'll just ignore them for the moment.

Without putting the math in here, for red and green, use a 120Ω resistor on each wire. For blue, use a 110Ω in that one. That should get you in the ball park for directly driving them.

For any color you want to increase the brightness of, reduce the value of the resistor in that wire. If you want to decrease the brightness of a particular color, increase the value of the resistor in that wire.
 

zachholtzclaw

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You'd actually need to add current limiting resistors to each of the R, G, and B wires, instead of a single resistor to the V+ wire; and the resistors that are already there are probably low-balled for PWM, so we'll just ignore them for the moment.

Without putting the math in here, for red and green, use a 120Ω resistor on each wire. For blue, use a 110Ω in that one. That should get you in the ball park for directly driving them.

For any color you want to increase the brightness of, reduce the value of the resistor in that wire. If you want to decrease the brightness of a particular color, increase the value of the resistor in that wire.
Would these work ?
https://www.amazon.com/Parts-Express-Flameproof-Resistor-Pcs/dp/B000AYHAH2
https://www.amazon.com/Resistor-Carbon-Film-110-Watt/dp/B00CHTKTGM
 

AllanGH

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Yup.....That would be my first attempt at hooking it up.

After that, take note of the brightness of each element (it should light-up as nearly white with all leads connected), and adjust the resistances to meet your tastes.

An alternate approach that I didn't think of, before, would be to use 3 - 150Ω to 200Ω trim pots--one in each lead--to adjust the color mix on the fly.

If you haven't already ordered the resistors, then that might be the way to go.
 
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zachholtzclaw

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Sep 30, 2017
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Yup.....That would be my first attempt at hooking it up.

After that, take note of the brightness of each element (it should light-up as nearly white with all leads connected), and adjust the resistances to meet your tastes.

An alternate approach that I didn't think of, before, would be to use 3 - 150Ω to 200Ω trim pots--one in each lead--to adjust the color mix on the fly.

If you haven't already ordered the resistors, then that might be the way to go.
shouldnt i be able to change it with my mother board's rgb software (RGB Fusion) since its on a led header ?
 

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