This little LED mod ... help and suggestions needed....

H

Hyper_Psycho

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Spencers stores had these goth skullhead thingies for sale (like 1 buck for a piece of metal. I got this skull and bones that I thougth would look badass as hell if it were to shine red light in front of my computer. The thing is that I dont know much about LEDs and how to exactly make one stay on without much modding. I heard that those oldschool cables that came with cd rom drives (4 pins, connects to sound card) could be use to have an always on LED. Would it be possible to have something like:

Motherboard --> cdrom/audio/oldschool cable --> front pannel with and LED in the center glued --> skulll ---> redness emitted from the LED

?
What voltage LED would I have to get? Can I get thee at a local radio shack?

Is there a alternative better way to hook up an LED. Perhaps using onboard fan connectors ? How many volts are those ?

I know that regular PSU power cables are 12v and LEDs with that support are huge or you have to have a transistor. So, I am not messing with that. As soon I get home I'll post pics to make this thread clearler. Please help me out.
 
Personally I have modded one of my cases with LEDs

I use the onboard fan connectors for my power, I just cut off the end of an old fan I didn't need and stripped it down.

Yes you can get these LEDs from just about any radioshack, that's where I got mine, you're going to want to get 12V LED's, the amperage won't matter.

When you go to hook it up, you're going to want a PARALELL CIRCUIT, not series. The more lights you connect in series the more dim your lights will be. Currently, I have over 25 LEDs all being powered from one source of the board fan connector in a parallel circuit, with no light loss.

So the way you're gonna want to do it is

keep in mind, there are 3 wires on the fan cord, you only need 2, the red for the Live (+) and the black for ground (-), yellow is for voltage montoring of fans, so you can just cap that one off.

Mainboard > fan connector > fan cord with no fan attached > leds

hope that helps :)
 
No, don't use the fan header. It supplies 12 volts, which is way more than you need for a simple LED. Using this as a power source would require a fairly hefty resistor and more trouble than it's worth.

LEDs typically require a voltage of about 3.3 volts. This can be tapped from any number of sources in your computer. Your idea to use the front panel header is perfect. Just go to your local electronics store and pick up an LED in the 3-4 volt range. If you pick a 5 volt LED, it may be dimmer than you like. Similarly, with a 1.5 volt LED, if you pick that, it will be too bright and probably burn out immediately or shortly thereafter. Something in the 3-4 volt range is usually ideal.

The rest of your plan looks good--have fun.
 
Hmmm ok... so something using the following

Dscn3440.jpg

Dscn3432.jpg

Dscn3435.jpg


would be possible ?

What voltage LED do I need to get ?
 
Pircio had it right. You either need to find a "12 volt" LED (one with resistor built in) or you can use 4, 3 volt LED's in series. I would go with the 12 volt simply because I have had bad experiences wiring LED's without resistors. If you find the right two pins on a fan connection stick with that for your 12 volt power source otherwise use one yellow and one black wire from a molex connector. As for the bundle of wires you had there LED's fit nicely in the little sockets assuming you can wire the other end with propper voltage. This lets you change the LED's whenever you want.
 
its pretty simple to work out the value of the resistor you need to use to drop the voltage down to something suitable for an LED.

Say youre using the 12v line of your PSU. The LED is going to draw around 2v (check the specs of the LED first) so you need to drop 12v-2v=10volts accross the resistor.
The LED will draw about 30mA (again check the specs of the LED you want to use, ultra bright ones draw more current)

Using V=IR, the resistor you need is given by R=V/I

= 10/0.030 = 333 ohms, so you would use the nearest resistor value to this.

Or you could do what eternal spire said and use enough LED's to use up all of the 12v wired in series- if the LED's need 2v you would need 6 of them to be safe with 12volts.

As regards the use of the CDROM audio cable, im not sure where you want to plug it into as the audio in on the motherboard does not supply any voltage to the cdrom through that cable. It is the same as the line-in mini-jack on the back of your case. I would use the fan headers on your mobo- although the audio cable might fit on those, then you would get a 12v supply.
 
Well I dont want to mess with the 12v stuff because its too damn compicated for me costs me more money too.

Is there anything from the motherboard that shoots out 3V that is suitable for a LED ?
 
Yes, there is a 3.3 volt line, found in the ATX connector. It's an orange wire.
 
Wow, give me that skull:D j/k. I found this in a Disney outlet store for $0.13. The eyes are blinking red LEDs, it's perfect match..hehe.

Sorry couldn't help with LED question, but just an idea.

T2.jpg
 
Originally posted by Steak
Wow, give me that skull:D j/k. I found this in a Disney outlet store for $0.13. The eyes are blinking red LEDs, it's perfect match..hehe.

Sorry couldn't help with LED question, but just an idea.
Click to expand...

haha thats pretty neat and very cheap !

Originally posted by xonik
Yes, there is a 3.3 volt line, found in the ATX connector. It's an orange wire.
Click to expand...

I really dont want to hack out a wire out of my connector ....
 
well those are pretty much your two options. Use 12 volt or split your 3.3 volt line. Nothing gets handed to you perfectly in electronics. You have to make it work.
 
Originally posted by eternalspire
well those are pretty much your two options. Use 12 volt or split your 3.3 volt line. Nothing gets handed to you perfectly in electronics. You have to make it work.
Click to expand...

Damn ... where could I get the transistor and the needed material

I dont have that machine that melts plastic over wires so I will have to make wires look ghetto as hell
 
Oh God... Why is everyone trying to make this so difficult.
A. Buy an LED and note its characteristics (ex. 1.5V forward drop, 20ma current draw)
B. Plug the variables into this equation: Resistor in Ohms = (Supply Voltage - LED Voltage Drop) / Current in Amps (ex. To use the LED in A on a 5V line, do R=(5-1.5)/.020=175 Ohms)
C. Buy the damn resistor (or ones that are close in value)

"its too damn compicated for me costs me more money too" is not an excuse. Being lazy *maybe*, but the damn resistors cost pennies (or like $.50 if you buy from RadioShack). Honestly it is dead simple.

-special [k]
 
Originally posted by specialk
Oh God... Why is everyone trying to make this so difficult.
A. Buy an LED and note its characteristics (ex. 1.5V forward drop, 20ma current draw)
B. Plug the variables into this equation: Resistor in Ohms = (Supply Voltage - LED Voltage Drop) / Current in Amps (ex. To use the LED in A on a 5V line, do R=(5-1.5)/.020=175 Ohms)
C. Buy the damn resistor (or ones that are close in value)

"its too damn compicated for me costs me more money too" is not an excuse. Being lazy *maybe*, but the damn resistors cost pennies (or like $.50 if you buy from RadioShack). Honestly it is dead simple.

-special [k]
Click to expand...

Alright ... I'll try to do this ... thanks on the info
 
Originally posted by specialk
Oh God... Why is everyone trying to make this so difficult.
A. Buy an LED and note its characteristics (ex. 1.5V forward drop, 20ma current draw)
B. Plug the variables into this equation: Resistor in Ohms = (Supply Voltage - LED Voltage Drop) / Current in Amps (ex. To use the LED in A on a 5V line, do R=(5-1.5)/.020=175 Ohms)
C. Buy the damn resistor (or ones that are close in value)

"its too damn compicated for me costs me more money too" is not an excuse. Being lazy *maybe*, but the damn resistors cost pennies (or like $.50 if you buy from RadioShack). Honestly it is dead simple.

-special [k]
Click to expand...

LOL

thats exactly what i said way back up there somewhere . . .

the resistor (not transistor, thats a completely different thing) that you need will cost you about 5 cents (if that) from radio shack or whereever you get stuff from in the states . . . its about the easiest electronics thing you can ever do- if your building and setting up whole computers this should be a peice of cake- otherwise you shouldnt be anywhere near them :D
 
Easy - Just take the front panel power LED wire and put a pair of LED's on it and place those in the eyes of the skull

Easy power, always on


OR you could use the hard drive activity LED's, that might look cooler when they are flashing
 
What about that fun vestigial 6 pin connector?
I know a lot of psus have it and it is very nice to use 5V 3.3v 3.3v Gnd gnd gnd

its that funny rectangle thing...
 
Originally posted by awdark
What about that fun vestigial 6 pin connector?
I know a lot of psus have it and it is very nice to use 5V 3.3v 3.3v Gnd gnd gnd

its that funny rectangle thing...
Click to expand...


Hmmm would that work ?
 
there's nothing wrong with using a 12 volt led, i really don't see what the big deal is, if you just run it off of ANY 12 volt connector on your board, you won't have to mess around with resistors or any of that if you don't want to. Finding a 12 volt LED and taking it right off of the onboard fan controller is quick, easy, and CLEAN, meaning no messy in-case wiring.
 
Originally posted by pircio
there's nothing wrong with using a 12 volt led, i really don't see what the big deal is, if you just run it off of ANY 12 volt connector on your board, you won't have to mess around with resistors or any of that if you don't want to. Finding a 12 volt LED and taking it right off of the onboard fan controller is quick, easy, and CLEAN, meaning no messy in-case wiring.
Click to expand...


thanks on the suggestion .... does radioshack have 12v LEDs ? I dont remember seing em
 
Originally posted by pircio
there's nothing wrong with using a 12 volt led, i really don't see what the big deal is
Click to expand...
At least 3 problems I can think of:
1. Price - compared to a single regular LED and a resistor you will invariably pay more for one with a built in resistor (which is what would make it a 12V LED)
2. Availability - I have seen 5V LEDs, but I have not seen 12V ones. Please post where one could buy them.
3. Ease of use - Ok, so maybe this isn't a problem, but it's not a big selling point. Considering how easy it is to buy a regular LED and a resistor from a local RadioShack (as opposed to the hard-to-find 12V variety), I would be surprised if you believed it would be a time saver.

Ohh... and egon_dude, you certainly did say that above! However, it seems like people don't realize how easy it is to do.

-special [k]
 
Originally posted by Grizzy
Easy - Just take the front panel power LED wire and put a pair of LED's on it and place those in the eyes of the skull

Easy power, always on


OR you could use the hard drive activity LED's, that might look cooler when they are flashing
Click to expand...
By far the simplest way out of everything, period. No muss, no fuss.
Originally posted by Hyper_Psycho
hmmm that might work ... but wouldnt 2 leds glow less because they are in a chain ?
Click to expand...
Not if you hook them up in a parallel circuit. Just google for the difference between parallel circuits and series.

The amount of misinformation/overcomplication in this thread is silly.
 
Originally posted by waddles
Not if you hook them up in a parallel circuit. Just google for the difference between parallel circuits and series.

The amount of misinformation/overcomplication in this thread is silly.
Click to expand...
You know, it is silly how much people think they know, which turns out to be mistaken. There will be a difference. Parallel and series circuits ARE different (for LEDs, with the same LEDs, for a parallel circuit, the forward voltage drop will be constant while the current draw will be the sum of the LEDs current draws, and for a series circuit, the forward voltage drop will be the sum of the LEDs' forward voltage drops and the current draw will be constant). However, you are assuming that the power LED is a constant voltage source, when in fact, motherboards have a resistor in series. Do the calculations, I don't have time...

-special [k]
 
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