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using silent fans to build myself a...

Posted: Thu Nov 10, 2011 4:45 pm
by mzimmers
...room ventilator.

I smoke cigars (yes, I'm one of those disgusting people) in my den. Currently I use a Vornado fan to exhaust the smoke. It works, but it's loud enough that my ears ring when I shut it off.

So, I was toying with the idea of getting, say, 4 120mm fans, and a small PS, and building a thin box to put on my window sill for the same purpose. How incredibly dumb is this idea?

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 9:14 am
by Deucal
It does seem that all household fans are designed only with moving air and no thought for noise pollution.

I'd say go for it. I would also think about a speed control for the fans.

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 12:08 pm
by CA_Steve
Don't know if the cfm would be high enough to make a difference. Are you using one of these things?

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 12:13 pm
by mzimmers
Steve -

No, the model I'm using is out of date, but it's more like this one:

http://www.vornado.com/product.aspx?Cat ... be00b4a9ee

And, I'm sure I can't match the CFM, but I don't have to. If I can just get some decent flow, that'll be enough.

My concern is whether mounting fans in a 2x2 pattern will somehow result in an airflow pattern where one fan disrupts another, but I'm willing to try it.

Any idea what would be a good PS that would have connectors for four fans?

My four fan block

Posted: Sun Nov 13, 2011 5:55 pm
by Zolishoru
Here's my similar build which I made a few years ago, and still using it on (almost)daily basis(as you can see, they are pretty dusty :lol: ).
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The switch in the middle of the block change the voltage of all four fans, between 7.5/15V(the fans are connected in two groups, each group with two fans in parallel; the switch change between the parallel/serial mode of the groups to 15V); the on/off switch is on the cable.
The power block(15V/3A) is from an old laptop, the fans(120X120X38mm) are coming from old rear-projection LCD TV's.
At 15V, it sound like hurricane, as expected, but it moves a LOTS of air; at 7.5V is pretty much silent.
The the fans are most efficient(move the most amount of air) mounted on a stand away(>10") from all surfaces, standing on surface(desk) are not that efficient.
If I would build a similar unit today, I would use Scythe Kaze Ultra 3000RPM fans, and I would build on a speaker stand with weight at the bottom, and OC, use the half/full switch. As power supply, I would use a 12-15V/3-5A brick.

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 6:11 pm
by mzimmers
A few questions:

1. what is "OC?" You don't mean overclocking, do you?
2. what do you mean by a "speaker stand?"
3. I'm sort of a power supply novice: will I find one with 4 connectors that will match those Scythe fans?

Thanks.

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 7:19 pm
by CA_Steve
Heck, you might try the one I linked. Claims to be as quiet as a desktop pc :) Instead of really loud fan to exhaust the smoke, use a quieter one to filter the crap out.

If you go the build a fan route: Consider looking through your pile of no longer used wall warts. Find one that has 9V or 12V DC out at enough mA to run your four fans. (Should be in the fan's spec). Get a Fan Mate 2 to dial in the rpm/noise and go MacGyver it together.

wall wart output -> fan mate -> 4 fans.

Scythe Kama Flow 120mm show 0.3A @ 12V. Then again, that's $60 for the fans, $9 for the fanmate 2. So $70 plus a wall wart that can put out 1.2A.

I really think you ought to look for one of those specialized smoke filtration dealies that can sit next to the ashtray. Solve the problem at the source. Or het some nicorette gum :D

Or, maybe one of these honking big 250mm fans will work.

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 7:44 pm
by mzimmers
Wow...that 250mm fan looks ideal; I didn't know they made case fans that big. And, it seems pretty damn quiet, too.

It says it uses a 4-pin power connector; but I don't think that's definitive (more than one kind of 4-pin, right?)...so, what kind of PSU would you use with that?

This could make this project *really* easy.

And, I hear what you say about using a filter instead, but I'd prefer to just exhaust it to the outside. Plus, the Czonka Smoker Cloakers are a lot more money than going this route.

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 8:10 pm
by cordis
They do make external 4 pin power supplies, you see them sometimes for external hard drive setups. Here's one I found with a basic google search: http://www.ebay.com/itm/External-Power- ... 0170366699
One of those would be the obvious way to go, with a fan controller in the middle, of course. But a dc supply from someplace might also work, if you're willing to do some wiring.
As far as the big fans go, I've tried a few and most aren't completely quiet at full speed, I'd definitely go with fan control to keep it as quiet as you like. A block of four may be more flexible, but I'm not sure if it would move more or less air than a single big fan. Eh, could try both ways and see. Have fun!

Re: using silent fans to build myself a...

Posted: Sun Nov 13, 2011 8:59 pm
by Zolishoru
mzimmers wrote:A few questions:

1. what is "OC?" You don't mean overclocking, do you?
2. what do you mean by a "speaker stand?"
3. I'm sort of a power supply novice: will I find one with 4 connectors that will match those Scythe fans?

Thanks.
1. Of Course
2. Something like that: http://www.sanus.com/ap/en/products/spe ... eater/HTB3 or http://www.futureshop.ca/en-CA/product/ ... 61851.aspx
3. Use a power supply* something like cordis linked in the previous post, and use the included(with the fans) molex-3pin fan adapters(you can daisy-chain them) to connect the fans, if you don't want to tinker with soldering iron and heat-shrink ;) ; the same can be applied to the 250mm fan case(pun intended)
The main question is, how much airflow do you need? And how much noise do you accept for that airflow?

*If you choose to go with that specific model, it doesn't drive directly the fans, because of the missing ground connection; mod needed.