Cathode as h.d.d activity light

[dowmace]

Ok I'm unsure if this would work, I want to use a cathode as my hdd activity light right? well what if I pulled the +12v from a molex and the negative came from the mobo header? would that work or would there not be enough ground in the mobo to hold the voltage? thanks for any help:)

[DaveSauce]

The light headers put out a little more than 2-3v......take a voltmeter to it and test for yourself. This will differ depending on your mobo....my Epox 8RDA+ puts about 1v on the power LED, and it puts a varying amount on the HDD light...i would say from 0 to 3 or 4. The best way would be to test it with a voltmeter.....I know my power led does about 1 because ive tested it....

anyhow, I originally tested it because my nice blue LEDs that I replaced my old ones with won't work on the power for my epox. they worked on my asus, but not on this mobo. Reason is they're 4.5 or 5v blue LEDs. I know the old ones from my antec case will work, because I tried them....but my new ones don't. My HDD light works, just not the power.....heh.

Anyhow, I don't think you could power a CCFL off that. First, I dunno how many amps the mobo headers can handle (you don't want to short anything), and second I know they don't provide enough voltage to power a CCFL. They put out max 5v or so (untested)....you'd need a small transformer between the inverter and header, or you would need a custom inverter (which I have no idea how to make, hehe).

It might be possible, but you'd have to find out the limitations of the mobo header....

[Dc5e]

if you hooked up +12 from PSU and Ground from Mobo, wouldn't that mean the mobo is reciving 12 or so volts? i'm not exactly sure. You might be able to use a transistor as a switch like a relay. That might work, but i'm not exactly sure what the wiring diagram would look like.

http://metku.net/index.html?sect=view&n=1&path=mods/sahkooppi/index_eng#transistori This might work, where the left side of the diagram is hooked up to the motherboard, and the right side is hooked up to the cathode instead of all the LED's, if you do this, make sure the motherboard isn't getting the 12v

http://metku.net/index.html?sect=view&n=1&path=mods/vilkkuvalot2/index_eng
Also, you might want to try using that opto-isolator (TIL198), i'm not sure how it works, but i guess it will protect your system.

[Flewdefur]

could there be some way to take a sound activated CC and instead of the mic wire up the power from the Hard drive activty light? i dunno how all this works though...

[Cyberwiz01]

A CC flashing like that would probably give you a seisure :P

[pby5cat]

The HDD light header on the mobo only puts out 2-3v when active. So defenitly use an opto-isolator, to proctect mobo, and replace the speaker from a sound activated with the outputs of the opto. Though i don't see why that won't work, im not an expert in electronics, i'm going of the Electronics class i took 3 years ago in my freshman year of high school.

[Captain Slug]

A) You'll need to use an optoisolator for that.

You could use this diagram
http://www.bit-tech.net/images/article/58/circuit.jpg

But ignore all the stuff on the right and replace the first 10k resister with the CCFL inverter and it'll work.

B) I don't think the CCFL will be able to strobe but it will react to the changing input enough to pulse. The inverter is sinking too much current to be responsive to fast changes in input.

[Dc5e]

do you happen to know where i can get one, or do you know the part number? i'm having a hard time finding one

[pby5cat]

Cpt. Slug: if u place the inverter into the circuit and connect the 12v to 12v the ground to pin 5 of opto, that will not work. there needs to be a ground. thought if u hook the cathode to 12v and ground like normal, and replace the microphone with pins 5 and 4 that should work.

opto-isolators should be a most local electronics shops and its usually one size fits all, just ask for an opto-isolator.

[Dc5e]

whats the difference between these two? http://www.allelectronics.com/cgi-bin/category.cgi?category=search&item=4N27&type=store

and http://www.allelectronics.com/cgi-bin/category.cgi?category=search&item=4N26&type=store

One just says (photo-trans) is there any difference??

[Captain Slug]

Originally posted by pby5cat
Cpt. Slug: if u place the inverter into the circuit and connect the 12v to 12v the ground to pin 5 of opto, that will not work. there needs to be a ground. thought if u hook the cathode to 12v and ground like normal, and replace the microphone with pins 5 and 4 that should work.

opto-isolators should be a most local electronics shops and its usually one size fits all, just ask for an opto-isolator.

I was trying to show something like this. Which should work, right?
http://members.aol.com/captainslg/temp/ccfl_hdd.jpg

[Posidon42]

I would have to agree that I don't think you are going to get the effect out of this you are looking for. The CFL will not have the response time that an LED does and it will probably end up looking more like the inverter is failing than a cool effect. But if you get it working make sure you let us know how it turns out.

[PunkRawk911]

I was thnking about this and had an idea.
Instead of using something to switch on-off the power to the inverter, how about putting a solid state realy between the inverter and the CC. That way the inverter will always have power, and will be able to supply you with the necessary response time for a cool effect. You'd need to connect the relay to one of the lines in between the cc and the inverter, and hook up the HDD activity header to the other terminals of the relay. This way, when power goes from the mobo through the HDD light header into the relay, it will cause the relay to switch to the on position, and allow power from the inverter to get to the CC.


Just a suggestion, I don't know much about electronics.

[pby5cat]

I don't think that will work Cpt. Slug. the opto's pins 1,2 are the inputs, pins 5,4 are output, and pin 6 is a bypass. the way u have it connected your just bypassing the hdd signal.

PunkRawk has a good idea. insted of the sound activated idea, just connect pins 5,4 to a relay and the other side of the relay put the 12v wire on one pin going in and run the wire from the out to the cathode, leave the black wire alone.

thought Posidon is also right.

[Jewfro]

I too understand little or circuitry, but all that I know points to that being a genius idea o_o.
Problem: Don't CCFL inverters send about 500volts through the line?

[KILLorBE]

Have a look in this (http://forum.oc-forums.com/vb/showthread.php?s=&postid=2033044#post2033044) thread.

[Jewfro]

Can you put that post in plain english o_O
Or give us a link that explains the terms and symbols used? Thanks!

[KILLorBE]

Welcome to the forums Jewfro

I can't make it much easier, I could upload some pics of the components used tho:p

T1 = Transistor = BD139, B stands for Base, C stands for Collector and E stands for Emittor.
R1, R2, R3, R4, R5 = Resistor.
The red, blue and green symbols are diodes (In this case they're LED's = Light Emitting Diode).
The optocoupler is an IC (Integrated Circuit) which has a build in LED and PhotoTransistor.

Connect the + wire of the Inverter to +12V as you normally would, and connect the - wire of the inverter to the Collector of T1.
HDD+ goes to the positive lead of your MOBO HDD Activity header, and HDD- to the negative lead.

I made the schematic so you can hook up more LED's to your MOBO HDD activity header, but as I said you don't need the LED's and resistors (except R2).

BD139, It can handle upto 1A, if you want to hook up 2 CCFL's you'll need some passive cooling.
http://diyaudio.8m.com/Bebet/BD139.gif


Optocoupler, Pin1 is where the dent is, to know where other pins are just count counter-clockwise.
http://www.buxcommco.com/page3/4n32.gif

[Jewfro]

Hehe thanks for the welcome and the dumbing down =)
E-mail me the other pic and I can put it up on my host.

The thing is it's not really the diagram that was messing me up, but those funky triangles with the arrows that aren't connected. Can you just explain those to me? Thanks again.

[repilce]

Wouldn't it just be easier to have a selenoid to do the work.. you could use the power from the mobo header to power on/off the selenoid and it can just realay the power to the light..?? i dont think you could use any old selenoid but i think (in that thereroy) would be the easiest way.. just like a car selenoid is set up..

[Jewfro]

Erm...but selenoids/solenoids work by using a magnetic field = bad for case mods. Plus it seems to me they might not switch fast enough since they rely on wire moving on a coil (note: all of this is from research in the past 10 minutes, before then I'd never heard of solenoids/selenoids).

ED: Here is an example of a diagram I can understand =)
http://www.jewfro.jhindu.com/stereo%20led%20diagram.bmp

[daemoslives]

wouldnt it be possible to just use a simple relay?
run the HDD light circuit through the switching circuit of a relay, and have that actuate the CCD?
Considering the basic property of a relay circuit is to use a low current control circuit to make or break an electrically isolated high current circuit path. I think a relay would fit this application perfectly, and it produces a minimal electromagnetic field, something of which cant be said for soelonoids.

A single pole throw relay is all that would be needed, providing you can find a relay that actuates on the 2-5v that the HDD activity light provides. And to prevent inductive kickback ( electricity generated when the relay is released from active to neutral, providing a reverse current ) a diode installed into the relay itself would help to prevent damage to your motherboard.

This site provides a great explanation as to how relays work
www.eatel.net/~amptech/elecdisc/relays.htm (http://www.eatel.net/~amptech/elecdisc/relays.htm)

The only drawback I've noticed so far is, finding a relay where the coil is actuated by 2-5v. I checked radio shacks website, and their relays go as low as 12v on the actuator coil....

Edit: The other drawback would be the clicking of the relay... that may get mighty annoying, especially when defragging, or running another program that accesses the HDD frequently and rapidly

[Dc5e]

also, relays may make a slight delay, thats probably not much of a problem, but i'd say an Opto-Isolator is the best choice. I'm planning to buy some soon, so i'll see how it goes

[daemoslives]

gad, i feel like a moron, i just noticed the prior reply about using solid state relays... duhhhhhhhhh :rolleyes: