Help with home-brewed electronics

[Herr Rogers]

I'm building an external watercooling case, and need to power three 120mm high speed panaflo fans. I'm looking for some way to connect a circuit board to the wall outlets, then somehow wire my three fans (without molexes) to the circuit board. Is this possible?
For all you visual people:
http://img384.imageshack.us/img384/4209/plan7hf.jpg

[seadave77]

Sure it's possible, but if you don't know what you're doing you could kill yourself.

Basically you would have to convert the AC to DC and lower the voltage. Then you hook your fans up with some type of switch to the DC voltage.

There's some details I omitted but thats the basic jest of it. I won't recommend you do it though if you don't know what your doing. The voltage coming out of the wall can kill you.

[Herr Rogers]

I realize I could kill myself, but I /REALLY/ don't wanna have to shove a whole power supply into my external watercooling case and only use it's 4 pin molexes. Is there ANY alternative that isn't as big as a normal PSU?

[ErikD]

Hmm, all you are running is some fans and nothing to sensitive? You might want to look into using an external transformer, like that used by smaller electronic devices such as routers. If you find one that supplies the correct voltage it would remove the problems of voltage conversion and reduction. Then I would think that hard wiring the fans would be easy enough, or making a circuit board if you want to be fancy.

Of course I would have to agree that if you are really unsure of what you are doing you probably shouldn't be doing it. Not only can you hurt yourself, but you could damage the equipment, or burn the house down. Not that it has ever stopped me from messing around with things though. :bang head

[The_Jizzler]

Hmm, all you are running is some fans and nothing to sensitive? You might want to look into using an external transformer, like that used by smaller electronic devices such as routers.


thats what i did. just found one that did near an amp and all is well. i dunno about you but i somehow have little transformers all over the place. guess i never throw them away lol. so i just set my transformer in my ext. box, and used some female spade cons. to plug the wires from the wall to the prongs on the tranny. then the hot lead from the tranny to a rheostatto the fans, with the ground straight to the fans. works like a champ. however if i did it again id just find a lower voltage supply, instead of the rheo as i never adjust them.

[ƒÓÒl]

Gotcha an easy, and actually fairly cheap way to do it bud, without burning down yourself or your house.

First buy 3 of these fan extension cables HERE (http://www.directron.com/3pincable.html). Cut off the ends you don't need (ie, the motherboard end. Save the max ammount of cable on the end the fan plugs into).

Strip the Reds and the Blacks insulation 1/2" and twist each group together. The yellows won't be used, as they are for RPM monitoring and can't reach your computer ;).

Now buy 1 of these small 4.6 amp power supplies HERE (http://www.mpja.com/productview.asp?product=15900+PS) and remove it's coaxial plug and strip back about 1/2" of insulation.

Slip on 1" of heatshrink tubing onto the joined fan wires (one for black group and one for red group).

Twist the stiped psu wire to the black fan wires and solder. Slide the heatshrink over the joints and shrink it in place.
Do the same with the red fan wires and the unstriped (that's without a white stripe) psu wire.

Viola. One small (and externally mountable w/hot glue or velcro) psu with 3 fan connectors. That psu I linked is capable of powering most fans you can buy, up to 18 watts each, but I'd leave a little more headroom than that, sticking to say a maximum of 15 watts per fan.

Also to note, it's powered by a computer type cord, and most computer buffs have those around. It doesn't look to be supplied.

[ƒÓÒl]

Oh, thinking further:

Plug a fan in and run it before you solder. Once we assume that since nearly everyone on the planet marks the negative/ground/neutral wire with a stripe, be sure an engineer somewhere assumes otherwise.

You can use that psu to power a reobus so your fan's are controllable. Most of them already have fan plugins built in, and would only require adding the necessary plug to the psu's output wire. Usually a floppy plug which can be snipped off your main psu's line without harm (though voiding it's warranty).

Caution though, for busses with a display and lights on them, you'd need to factor in the ammount of power it takes, and adjust the fan maximum wattage accordingly so as not to smoke that little psu.

Being powered seperately from the PC, you'd need a switch to turn the fans on and off. Put it in the middle of the red wire's connection to the power supply.

As I pondered what I'd said earlier, hot glue may not be the best mounting method for it, as that little psu will get pretty warm and soften up it's mounting glue.

And finally, if you have a 12 volt pump, you might even use a second of those little power supplies (cheap enough eh?) to power it inside the external box. You'd have to check the pump's specs to make sure it's not too much power draw...I've never owned one. Keep in mind that it would NOT come on with the PC like an in-the-case one would.

[Caeberos]

well I am not sure what your budget is, but you can always buy 120v fans and use a light dimmer to control them

[Herr Rogers]

Oh, thinking further:

Plug a fan in and run it before you solder. Once we assume that since nearly everyone on the planet marks the negative/ground/neutral wire with a stripe, be sure an engineer somewhere assumes otherwise.

You can use that psu to power a reobus so your fan's are controllable. Most of them already have fan plugins built in, and would only require adding the necessary plug to the psu's output wire. Usually a floppy plug which can be snipped off your main psu's line without harm (though voiding it's warranty).

Caution though, for busses with a display and lights on them, you'd need to factor in the ammount of power it takes, and adjust the fan maximum wattage accordingly so as not to smoke that little psu.

Being powered seperately from the PC, you'd need a switch to turn the fans on and off. Put it in the middle of the red wire's connection to the power supply.

As I pondered what I'd said earlier, hot glue may not be the best mounting method for it, as that little psu will get pretty warm and soften up it's mounting glue.

And finally, if you have a 12 volt pump, you might even use a second of those little power supplies (cheap enough eh?) to power it inside the external box. You'd have to check the pump's specs to make sure it's not too much power draw...I've never owned one. Keep in mind that it would NOT come on with the PC like an in-the-case one would.

It sounds like you really know what you're talking about, but would you mind making a picture? I'm not even going to /try/ to comprehend electronic set-ups through words. Thanks!

[ƒÓÒl]

Sure thing BRB.

And 120 Volt fans isn't a bad idea, but I have yet to find a quiet one (if that's a concern).

[Herr Rogers]

I await the drawing, I hope it isn't too late to ask if you could make the lines color coded to the color of the actual wire.

[ƒÓÒl]

Here they are, two options. One using a fanbus/rheobus like a sunbeam fan controller, the other like I first posted (no fan control).

http://home.wmis.net/~jberg/RheobusPower.gif http://home.wmis.net/~jberg/RemoteBoxPower.gif

How's that for color coded with correct wire placement? :D

Forgot the white stripe in the first pic, it's going to the floppy molex's black wire. Sunbeam I'm told makes a nice rheobus, it's a simple fan controller using variable rheostats to change fan speeds. It already has the plugins for fans on the back of it, and is usually sized to mount in a CD bay.

The switch isn't included in the second one, but I showed where it would go.
This will only turn off the fans, not the power supply itself.

[stool]

As its external, go for the 120v AC fans. You'll save yourself an awful lot of time and effort.

[Herr Rogers]

Thanks fool. Awesome drawings.
If I just snip the yellow wires, couldn't I touch them and get electricuted?

[Herr Rogers]

As its external, go for the 120v AC fans. You'll save yourself an awful lot of time and effort.
too late.

[Captain Slug]

Thanks fool. Awesome drawings.
If I just snip the yellow wires, couldn't I touch them and get electricuted?
12V 1amp is a negligable load and can't hurt you.

[zebkoolindc]

You are running water tubes from your computer to this external box, right?

Why not run two wires with it also and save you from buying a new power supply when you already have one in your pc.

Just tie into a molex in your pc, and run 12v (yellow) and ground (black) out to external box. Then split it out like in Fool's pict.

[ƒÓÒl]

I don't think the yellows would actually carry a voltage. Since it's the fan's RPM indicator wire, I think they just connect to ground in pulses so that the motherboard can pick up an RPM from counting the pulses.
They can be shrink wrapped to the other wires also to prevent anything crazy happening.

As zebkoolindc pointed out, you can run extension wires from the PC along with your waterlines if you choose. There's some spiffy ribbed hose with an 1 1/4" diameter (kindof like a vacuum cleaner hose) that you could run it all in between boxes. Nice neat and snag free too. Some Krylon Fusion would make it any color you choose too.

Just some more ideas I'd thought of before, to do what you are. I chose instead to plug everything into a single powerstrip/protector, so one switch turns it all off for the night...pump, fans, computer, monitor everything. It is a heavy duty strip w/a 12 gage cord.

[RoadWarrior]

well I am not sure what your budget is, but you can always buy 120v fans and use a light dimmer to control them

Light dimmers should nevereverevereverever be used for controlling motors. They are designed purely for controlling non-inductive loads, such as for example, a light bulb. One can get ceiling fan speed controllers though, which are designed for running motors through. Inductive loads such as motors, and anything with a big coil in it, cause a surge current at startup and and a back EMF when power is removed. This is due to the coil "charging up" when powered and discharging when power is cut. Thus one risks the dimmer burning out or catching fire, possibly sometime when you're not expecting it to, like when you left things running and ran out to the store when there's a slight power glitch. Light dimmers may not even deliver regular AC and even a high rated light dimmer and a small motor may not work together, because it's not putting out the sinusoidal 60hz AC power the motor is designed to operate from.

So use light dimmers for dimming lights and motor controllers for controlling motors.

Road Warrior

[Herr Rogers]

I don't think the yellows would actually carry a voltage. Since it's the fan's RPM indicator wire, I think they just connect to ground in pulses so that the motherboard can pick up an RPM from counting the pulses.
They can be shrink wrapped to the other wires also to prevent anything crazy happening.

As zebkoolindc pointed out, you can run extension wires from the PC along with your waterlines if you choose. There's some spiffy ribbed hose with an 1 1/4" diameter (kindof like a vacuum cleaner hose) that you could run it all in between boxes. Nice neat and snag free too. Some Krylon Fusion would make it any color you choose too.

Just some more ideas I'd thought of before, to do what you are. I chose instead to plug everything into a single powerstrip/protector, so one switch turns it all off for the night...pump, fans, computer, monitor everything. It is a heavy duty strip w/a 12 gage cord.

I really thank your in-depth posts fool. You are awesome! Now that I think about it, running it from the computer really would be a better idea. The problem is though, that they don't sell very long extension cords, so could I cut the cord in half of one extension cord and just add more wire in there? WHich type of wire would I need? A picture of what I'm talking about:

http://img161.imageshack.us/img161/9012/untitled8qj.jpg

P.S. I was planning on using it's on powerstrip anyways. Good idea eh!?

Thanks again fool, and thanks zebkoolindc. My dad brought up zebkoolindc's idea and I immediately shot it down. Maybe I should listen to pops.

[ƒÓÒl]

Yes you can do that. But don't do it on a motherboard fan connector, use a molex like the CD drives use. The motherboard fan headers cannot handle the amperage draw of a single large fan, let alone 3 or 4 large ones. It will stop working quite quickly...maybe harming other things at the same time.

For a molex drive connector and the wires I linked, use this way: Fan red to molex yellow (that's the 12 volt line from a power supply...really!) Fan black to molex black.
As I understand it, most power supplies use a fairly standard 18 gage wire. AutoZone has the wire that would work in small spools on their rack, in different colors if you so choose, and the heatshrink tubing too. 16 gage is fine too (smaller number=larger wire).
In the remote watercase, you can still join all 3 fan cords together just like I illustrated.

Test before soldering to make sure you have them wired correctly. If they are wired backwards, the fans will not spin at all.

And Pops may well have been right. I'm a Dad too, my oldest is 13 ;)

[ƒÓÒl]

Another thing, instead of cutting off a molex connector and killing your PC powersupply's warranty, you can twist the incoming wire and solder it unattached to anything. Then you can use it as a solid pin inserted into the unmolested molex connector. A little electrical tape or a zip tie will keep it plugged in.

One thing I've learned is that it's handy to keep warranties alive...you never know what's going to happen.

[Herr Rogers]

Ok. This is what it's looking like so far.
http://img233.imageshack.us/img233/88/untitled5xk.jpg

Basically I need 4, 3 pin extension molexes. One will be used to carry electricity from the PSU to the external watercooling enclosure. The other 3 extensions are only used so that I don't need to modify the original fans' wires, and I can sell them whenever I'm done. Do I not need the yellow wires at all? I read what you said earlier about red to yellow, but I wasn't sure (again, I need pictures). The ends from all the extensions are cut off, and the reds and blacks are connected separately. Understand? Will that work?

[Navig]

Seems be a bit of confusion here, maybe I'll add more to the mix!

Yellow lines coming from a computer power supply typically denote the 12V line, Red the 5V line, and Black ground.

I suppose Yellow coming FROM a fan could typically be considered the RPM line. Most fans I know actually use blue wiring. I think it best to leave it without a specific color and just call it the RPM line.

Yes, you can just clip off the rpm line. Or you can pin and terminate it by itself, that way you can plug it into a motherboard header and monitor its rpm (even tho you are not powering from the header).

It seems you wish to run a cable from your computer power supply, a fair long distance, that will end up powering 3 120mm fans, external to the case.

This can be done in a variety of ways, perhaps the most blunt would be a wire that starts as a male 4 pin molex (to plug into an available female power supply 4 pin molex) and ends some distance later as a 3-headed 3pin termination to plug into each of the fans.

If you aren't comfortable rigging your own cabling plenty of places/folks would be happy to build you a custom cable (ie performance-pcs, or heck you can just contact me via pm).

If you want something with a little more versatility, you can pick up a molex pass thru pci slot device such as this:

Like this. (http://store.yahoo.com/directron/1132120.html)

and just get 3 pin extension cables to run to your fans.

Finally, the question you must ask yourself is: do you want these fans on a rheobus, so that you can control their speeds.

Wiring in a 5V/7V/12V toggle is fairly trivial, or you can get fancy with a variable device--there are plenty of front bay devices available, altho I've never seen a pci slot mount device.


navig

[Herr Rogers]

Okay. The thing is I need this to be done, and I need it done today. I want my rig to work by the end of this week, and I need to start bleeding and leak-proofing my setup. So....Maybe I should just make an easier to read diagram. BRB.

[ƒÓÒl]

That whole pic is correct except for the yellow power supply wire is the 12 volts and the red one is 5 volts.
Power supplies use different colors to denote different voltages, yellow=12 red=5 orange=3.3 etc..but DC fans use the old standby of red=positive black=negative no matter what DC voltage they run on.

Navig, I have several fans collected over the years, for the rpm line I've seen white, blue, yellow, green and even white w/red stripes used. I guess from the maker's point of view, there's only 3 wires so the third color isn't so important.
However on the extension cables I linked him yellow is the rpm wire, so that's what I was sticking with.

[Herr Rogers]

http://img223.imageshack.us/img223/1483/untitled8iv.jpg

newer, more updated pic. Just the 3 pin extension taht runs power from the case to the box will have some more wire added in to make it longer. This looks like it already does what it needs with the yellow. Notice that on the 3pin to 4 pin adapter, the yellow turns to red? These are all pics of the hardware I have sitting next to me, so this is how they woudl connect if you would use the molexes. Does it look right?

[juliendogg]

Why not just use an old AT PSU ? or even a microATX and wire the green wire and a ground to a 2 position switch for on/off ?

J.

[Herr Rogers]

Why not just use an old AT PSU ? or even a microATX and wire the green wire and a ground to a 2 position switch for on/off ?

J.

I was looking at those the other day. I will probably end up doing that later on, but I want to play with my computer this weekend and this is the easiest way to do that.