i need help wiring my case!

[dumass]

Ok, I have a 3 point switch (on - off - on2)

It is controlling my fan circuit, and I want the circuit to run on 12 volts, and be able to be switched on 5 volts (5volts = quieter when sleep)

If i connect it up as the pic i drew shown below, and have the line end up going to the black 12v wire of a molex conector, will this work when running the 5v line?

The fans = circle in square, and the circle and cross just equals two LED lights indicating which is switched on.

[surlyjoe]

as long as the current is not trying to run through the LED's to the fans it will work.(use a tap off the main,and a ground ,and U may need a resistor too)

[dumass]

now im more confused

(?)

[surlyjoe]

well. by your drawing it looks like you wanna try and put the LED's inline on the hot lead, you dont want all your power tryin to squeeze through the LED's.. what you want is a branch circut so the LED's light up when the fans are powered on. also I would wire it as 12v and 7v. 5 volts will barely spin the fan IMHO

[Áedán]

To do what you want to do with the LEDs means you'll have to change a few parts. The problem is that the LEDs only need a small current to flow otherwise they go pop! The fans require much more current to go around than the LEDs need to go pop.

If you connected it up the way you've proposed, you'd find that the LED that should be lit would go pop, and the fans wouldn't turn round either. Probably not quite what you want, unless you're looking to be hit by flying bits of sharp plastic from the LED!

You'd need a different switch, and a resistor in order to acheive it. I've thrown together a quick circuit diagram, but it's not the neatest I'm afraid.

AidanII

[surlyjoe]

THANX DOOD! Thank god someone stepped in before I had to try and draw something. lets just say I have a way of butchering even the most simple of drawings :P

[Áedán]

Originally posted by surlyjoe
THANX DOOD! Thank god someone stepped in before I had to try and draw something. lets just say I have a way of butchering even the most simple of drawings :P

Actually, I just used EAGLE Layout editor from Cadsoft. They do a freeware license for non-profit and evaluation. Check out Freeware EAGLE layout for more details. Needs a little bit of work on it's libraries for what I'm working on doing, but it'll handle schematics as well as board layouts.

AidanII

[dumass]

Ok, i think i got it figured out now.

What if i put the LEDs in parrallel, so they dont get so much current, I think that would work, but then would i have to still put a resistor in the parrallel bit of the LED so it doesnt blow up?

Also-

I would just use a 12v supply, and put a resistor in one of the options of the switch. That would alow less current to go through = slower fans = more quiet (did that make any sence?)does anyone know what types of resistor(s) i would have to use?

Here are what the following circuits will:

2x 120mm fans
1x 120mm fans
2x 80mm fans

Could i use the same type of resistor for all the circuits?

Thanks guys, i am hopeless at this (hence my name)

Attatched is a 'updated'fan circuit layout.

[B.A,Jinx]

Go to www.fanbus.com plenty of info and schematics

[surlyjoe]

Originally posted by AidanII


Actually, I just used EAGLE Layout editor from Cadsoft. They do a freeware license for non-profit and evaluation. Check out Freeware EAGLE layout for more details. Needs a little bit of work on it's libraries for what I'm working on doing, but it'll handle schematics as well as board layouts.

AidanII

thx man I'll try it!!

[Áedán]

Originally posted by dumass
Ok, i think i got it figured out now.
What if i put the LEDs in parrallel, so they dont get so much current, I think that would work, but then would i have to still put a resistor in the parrallel bit of the LED so it doesnt blow up?

Ahhh, I think a little bit of learning about electronics might be in order here! (; If I were you, I'd go and take a look at the link that was posted. In particular, take a look at this picture which is pretty much what you're looking at doing.

If you can make the time, it would be a very good idea to learn a bit more about electronics, as this would really help you work towards some pretty cool mods.

AidanII

[dimmreaper]

Awsome software Aidan! Thanx for posting that URL!

So like is there an internet resource that I can look the various component specs up with? I'd be able to set out and design a 1KVA ATX PSU then

[Áedán]

Originally posted by dimmreaper
Awsome software Aidan! Thanx for posting that URL!

So like is there an internet resource that I can look the various component specs up with? I'd be able to set out and design a 1KVA ATX PSU then

Erm, unless I've misunderstood you, you want to design an ATX PSU that can output 1KVA AC? :P

Perhaps 1KW worth of DC would be more useful? I'd recommend seperating the secondary supplies from the primary supplies unless you require serious output levels from the secondary supplies.

There's plenty of SMPS controller chips out there that'll do exactly what you ask. The most difficult part will be designing/winding the transformers for the sort of frequencies you're looking at using. Designs I've seen for homebrew high current SMPSUs generally have ended up using copper sheet to handle the current levels involved, rather than trying to use copper wire.

What I'd recommend doing would be designing a high current 5V switching regulator as a primary supply. The 5V regulator could feed into a 3.3V buck regulator for AGP/PCI cards, as the power levels will be much lower. The +12v, -12v and -5v lines can all come from a seperate switcher module as generally these lines are not such high power. The +12V would be a primary, and the -12v and -5v lines would be derived from the +12V line, as their loading is light.

This way, there is no interaction between the all important 5V and 3.3V lines and the auxillary 12V, -12V and -5V lines.

AidanII

[dimmreaper]

Originally posted by AidanII
Erm, unless I've misunderstood you, you want to design an ATX PSU that can output 1KVA AC? :P

That would be a typo What I meant to say is that I would be able to set out building a PSU using a 1KVA transformer

[dimmreaper]

Originally posted by AidanII
This way, there is no interaction between the all important 5V and 3.3V lines and the auxillary 12V, -12V and -5V lines.

Sounds like the way to go about it . . . could even disassemble an old AT PSU for much of the parts required for the 12V side of things.

[dimmreaper]

Originally posted by AidanII
There's plenty of SMPS controller chips out there that'll do exactly what you ask.

Ok, but were do I find out more info about 'em, spec sheets and the like? And equally as important, were do I purchase them?

[Áedán]

Originally posted by dimmreaper
That would be a typo What I meant to say is that I would be able to set out building a PSU using a 1KVA transformer

Whoa.. Hold on a second... You're telling me you've got hold of a 1KVA transformer. What kind of 1KVA transformer? Presumably you're talking about 60Hz magnetics here, rather than high frequency stuff?

If so, it's going to be interesting.... :P

AidanII

[dimmreaper]

Originally posted by AidanII


Whoa.. Hold on a second... You're telling me you've got hold of a 1KVA transformer. What kind of 1KVA transformer? Presumably you're talking about 60Hz magnetics here, rather than high frequency stuff?

Yeah, I got me a 1KVA transformer(It's like a 6" cube that weighs close to 30 pounds). But I'm pretty sure it won't work. It's only got a 4:1 ratio. It's for stepping 440VAC down to 110VAC. If you were to wire the primaries up to 110VAC you would get 27.5VAC naturally, which works out to like 37VDC when you rectify and filter it, which I think would be a bit too high for a 5V switching supply . . . . It might do for a 12V switching supply, it definately could make one hell of a 24V switching supply for big TECs.

[Áedán]

Originally posted by dimmreaper
Yeah, I got me a 1KVA transformer(It's like a 6" cube that weighs close to 30 pounds). But I'm pretty sure it won't work. It's only got a 4:1 ratio. It's for stepping 440VAC down to 110VAC. If you were to wire the primaries up to 110VAC you would get 27.5VAC naturally, which works out to like 37VDC when you rectify and filter it, which I think would be a bit too high for a 5V switching supply . . . . It might do for a 12V switching supply, it definately could make one hell of a 24V switching supply for big TECs.

You'd have a problem getting 1KVA out of it if you're wiring up 440VAC windings to 110VAC. If you do, you should find that you get 39V P2P out of it. There's no problem with that, as a switcher will work quite happily stepping down, and you'll get the same wattage out of the thing, unlike a linear regulator!

AidanII

[dimmreaper]

Hmmm . . . . maybe I'll use it then. I didn't pay for the thing though, so it's not like I'm in any hurry to use it.