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A LED Soldering project - Need some feedback

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Suppressor1137

Member
Joined
May 4, 2011
I'm looking to do some fun things with LEDs on my pc.

I have several unused 4 pin headers on my mobo that have smartfan utilities, such as tracking cpu temp or ambient case temp, Which adjusts the RPM of the attached fans.

I want to do this for a few LED strips, Or LED tape.

Is there a way to implement PWM functionality with LED tape so that they change brightness*or color?* based on the temps of your cpu/case? It would be pretty sweet to see the colors change as the temps start to crank up.*starts blue for 30-35c, then orange at the 36-40c range, and finally red at the 41-70c range* The second part is a bonus, if possible without another controller.

I'm Somewhat handy with a Soldering iron, Having used one to build a fpv drone and wing, so I'm okay with what needs to be done in that department, but I haven't got a clue on what is needed to accomplish this. I've only ever seen two lead LED tape for sale, + and -.

Would Rosin Core solder work fine?

Thanks :)
 

JrClocker

AKA: JrMiyagi
Joined
Sep 25, 2015
LED strips usually come with a controller of sorts.

You could build your own an run off the PWM signal. A PWM signal, run through an RC filter network will basically be a filtered DC signal from 0 to the max voltage.

Put the proper resistor in series and you can change the brightness.


 

bob4933

Member
Joined
Jan 3, 2014
LED strips usually come with a controller of sorts.

You could build your own an run off the PWM signal. A PWM signal, run through an RC filter network will basically be a filtered DC signal from 0 to the max voltage.

Put the proper resistor in series and you can change the brightness.

. Is there a way to manually tell the mobo what voltage signal to output? The only program I've seen that controls fan speed manually is SpeedFan software which is obnoxious as hell. I would think a solid state controller installed would far easier, but RGB strips come with one anyway, so whats the point? All that aside, changing color seems far easier than changing brightness of an led right?
 

JrClocker

AKA: JrMiyagi
Joined
Sep 25, 2015
Most motherboards have control where you can set the PWM signal by temperature.

Brightness is the easiest...the more current in the LED, the brighter it is.


 

bob4933

Member
Joined
Jan 3, 2014
Most motherboards have control where you can set the PWM signal by temperature.

Brightness is the easiest...the more current in the LED, the brighter it is.

Well, thats not the same with an RGB led. The PWM circuit would need a dedicated software to control it (I am not familiar with one). Also motherboard PWM circuits are WAYYYYYYYYY higher voltage than what is used on an LED like that. I'm just doin stuff in my brain, but doing this via motherboard PWM would be incredibly difficult, time consuming, and probably expensive. Probably a much easier solution out there.

edit : red voltage is under 2v, green is 2.5-3v, blue is 3.5v. Motherboards don't go down that far to my understanding, and go to 12v. That would fry an RGB led in a heartbeat. You'd need to install different resistors for each LED color, get it right, and THEN sort the PWM stuff on top of that.... or push a button on your remote? haha
 

JrClocker

AKA: JrMiyagi
Joined
Sep 25, 2015
If you read what I wrote:

- RC circuit on PWM output...filters PWM signal into DC
- a resistor in series with LED

Ohms law is your buddy to choose the resistor, and a single one is the easiest.


 
OP
S

Suppressor1137

Member
Joined
May 4, 2011
thanks for the replies, definitely some useful info! Yeah, a lot of work for sure. I thought i could be slick and use the pwm line on the mobo for automated brightness, similar to fan leds.
 

bob4933

Member
Joined
Jan 3, 2014
If you read what I wrote:

- RC circuit on PWM output...filters PWM signal into DC
- a resistor in series with LED

Ohms law is your buddy to choose the resistor, and a single one is the easiest.

Its not "one led", so "one resistor" wont work. Not starting a pissing contest here, I am just not seeing how your solution would work as OP wants.

- - - Updated - - -

thanks for the replies, definitely some useful info! Yeah, a lot of work for sure. I thought i could be slick and use the pwm line on the mobo for automated brightness, similar to fan leds.

I dont think you can vary the brightness of an LED with a PWM circuit
 

JrClocker

AKA: JrMiyagi
Joined
Sep 25, 2015
Yes you can.

And, yes you can. I'll draw you the simple schematic if you want to see.

OP asked if it was possible...it is. However, it is not the best way to do it.


 

bob4933

Member
Joined
Jan 3, 2014
Yes you can.

And, yes you can. I'll draw you the simple schematic if you want to see.

OP asked if it was possible...it is. However, it is not the best way to do it.

That may be a good visualization, because I am probably thinking of something entirely different here lol.