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how to build a 3 8 cm fan Answered

I was wondering if you could help me on how to build a 3 8 cm fan (taken from a laptop cooler) with usb double power and 4 female usb ports (2 female for each of the usb wires), with a switch for the 3 fans. I though that, if I supply energy from both of the wires, the 3 fans would be faster. Both of the usb wires are independent, but I take energy from both of them



5 years ago

All right, I wasn't sure about how would affect the voltage and the current to the fans and the computer. And I wasn't sure about series and parallel wiring. I'm not sure about this project, and for that, I'm trying to find and buy cheap 5V fans, whatever they are.

Thanks for your answer, I only want to build a USB fan, with a wire like an external DVD drive for netbooks

If you're using 3 5V fans, then wire them in parallel to one USB port.
I don't know what that will do to your battery of your laptop or to the efficiency of the fans, but it's worth some easy experimentation.
You also want to make sure that you aren't frying your USB port. Normally USB ports only take one fan, one flashdrive, one external hard drive, etc. so that is what those devices are rated for. If you wire a bunch of stuff together, even in parallel, the USB port might not be so happy.

I took this pictures from a broken laptop cooler (I'll try to find out it's problem and fix it). Now I know how to do it. But, can I do the same with the female usb ports?

I think that I'll use only 1 usb wire, I don't know...


P.D.: Do you know where I can buy 5 V fans? I can't find them...

Thank you

Aren't those 5V fans? (Honestly I don't know/can't tell.) If they say somewhere on them that they are, you could just use those. Just find the + and - terminals on your USB female port, get a male USB connector and wire the + and - of the fans to the corresponding + and - from the male from the + and - from the female. :)
I'm sure a quick eBay search could yield a lot of results. Also check Craigslist or your local computer/hobby/junk/electronics shop.

Yes, they are. But I prefer to try to repair it. If I can't, I'll use them. If I repair it, I'll buy some. Is it possible to make a hub usb without a printed circuit board, solding? Only for another female usb.

Hub USB? You don't need a circuit board, but you do need soldering. And a multimeter.
You are powering this off a computer right?
If you are, get a USB male connector - a broken iPod charger, flashdrive end, etc. You can buy those cheap too. Plug it into the female port on your computer. Use your multimeter to find the two little prong things that read 5V on the multimeter. Take the male USB connector out. Solder the two wires from the fans (corresponding to + and -) to the pins on the male USB connector.
I think that's what you're looking for....

Yes, I agree, but I mean, imagine the UBS wire, without the fans.

Is it possible to have 1 male connector and 2 female connectors, solding each of the little wires? Can it have problems in the future?

Thank you very much for your help, really.

I'm really not sure what you mean.
1 male on one end and the 2 female on the other?
1 female on one end and a male and a female on the other?
Your computer has a female port. That needs to get power to the fans.
If you put a male USB connector on the ends of those positive and negative (the red and black, respectively) wires to the fans so that power runs through them from the correct female USB port terminals, then the fans will run.
Having two USB female ports supplying your 5V fans (even if there are three of them) will give them too much voltage and burn them up. They might go faster for a little bit, but that is until parts inside the fans start to melt.
Three fans wired in parallel to one male connector, when plugged into a USB port, will work.
By the way.... what are you making this for?

I mean, something like the picture, solding. Just for fun, I'd like some outside fans for me, not only for my laptop, hehe. I had some idea about how to do it, but I didn't (and I don't) know if I was doing it wrong

sorry, I though that the file was uploaded: http://www.subirimagenes.cl/HMw

No it was! But is that what you're actually making? Is that a "work-in-progress" picture? If it is, then you're basically done. All you need is 5V to run through it and the fans will go. (Instructables hint: If you need to put in a link in a comment, highlight the text you want to be linked, click "Rich Editor," find the little thing with the world and a chain, and click that. Input the URL in the little box and click OK!)

OK, I had problems with this image uploader, but the only problem now is, solding, the four little wires, Can it have problems in the future? Beacuse there isn't a control circuit. I know that it will be slower than any hub usb, but, well, I want it 100% home-made.

Why are there four wires? I thought you had two coming off the fans.....

yes, you know, I need all of them for the 2nd female usb

This might help. The little humps in the drawing are the wires "jumping." They don't actually connect to that wire.

3 fans.png

Do you understand the difference between Series and parallel wiring?

If not then learn about it.

First thing that i need to point out is the fans probably run off 12V. Thenshould have labels indicating the voltage on them. If they are 12V fans the 5V from the USB connections won't power them. Wiring a pair of USB connections in series will give you 10V. If you wire all 4 in series then your giving the fans 20V and will burn them out. Assuming the 3 fans combined won't over load whatever USB connections your trying to use to power the fans.