Sunday, 27 June 2010

A cheap usb desktop fan ... ...

How to make a cheap usb desktop fan, I know you can buy them, but where's the fun in that ? and this one costs between £1 and £2, and takes about 10 minutes to make.
(and this time I took pictures :-))

Firstly a short rant, well not a rant, more a grumble. It seems to me that things have taken a turn for the worst in terms of how people view things, by things I mean appliances, furniture and just about everything in between, and when I say " a turn for the worst " I mean that no one seems to build anything themselves any more (well some people do)
Since we moved to our current house we have become more and more independent, how you ask ? well for a start we have more garden, and both my wife and I enjoy growing things (doesn't really matter what, as long as it's edible) so we set about turning some of the garden into production of fruit and veg, this in itself meant designing raised beds and such like, and of course building them, but again in this day and age we could have just gone to a diy shop and bought a raised bed kit, but we chose to recycle some wood and do it our selves, which worked out cheaper in the long run and only took a small amount of time.

So why don't we build or make things (or even fix anything) any more ? if you ask me we don't because it's easier just to buy it, obviously building a washing machine isn't going to be easy, but if your washer breaks what do you do ? When I first met my wife she had a washing machine, shortly after we got together it started to go wrong (nothing to do with me) so I decided to fix it (I can remember the look of panic in her eyes) I won't go into details but it was easily fixed, how many people would have just bought a new one ? the washer has since died, but it lasted nearly 6 more years (and had to be fixed a few times in the end) I agree that some things cant be fixed, and certain things shouldn't be messed with if they go wrong, but if it can be fixed, then why throw it ?

I heard a report a few years ago that a large percentage of children leaving school had no idea how to put up a shelf or change a fuse even, when I was at school (which wasn't that long ago) we got taught all kinds of things, we built coffee tables, with real joints, not just screwed together like the flat pack stuff you can buy, hell they even showed us how to apply veneers to it !
come on putting up a shelf is so easy, and it would only take 20 minutes maybe half an hour to show a room full of kids how to do it, but I guess they are too busy with sat's and such like (which I personally think are a waste of time, but we home educate so I generally feel most school based learning is a waste of time)

Anyway back to the usb fan.

As the weather has been hot for a change I decided I needed a little cooling on the desk, so I set about making a fan to run of the usb ports of my pc, this is how I did it.

Firstly I should point out that I take no responsibility for any breakages, this shouldn't cause any problems, it hasn't for me, so try it at your own risk.

Okay, stuff you will need -

Here's a picture

Stuff you will need.


  1. - a soldering iron is recommended, but you might get away with not using one.
  2. - a cheap battery powered fan, the sort you can get from pound shops that run on a couple of "aa" batteries.
  3. - some solder, again recommended.
  4. - if like me you use the kitchen table for this, then a bit of scarp wood will protect the table top and stop your better half worrying your going to damage it :-)
  5. - an old usb lead, mine was from an old mobile phone, but any type should be fine, if you don;t have one then you can buy cheap leads from the pound shop when you get your fan.
  6. - some pliers for cutting wire.
  7. - a screw driver to dismantle the fan, I used a philip's screw driver.
  8. - a sharp knife to cut the outer casing of the usb lead, or wire striper's if you have them.
  9. - and although it's not in the picture you may also want some insulation tape.
To work, firstly you need to cut the end of the usb lead, make sure you don't cut the end off that goes into the pc, then you need to strip back the casing and anything else to expose the 4 coloured wires.

    Here's another picture

    4 coloured wires.
    And another 

    You only need the red and black wires.


    Once you have got this far it's time to get into the fan, mine had 4 screws on the bottom, but yours maybe different, it may not have screws.

    Here's what mine looked like

    I had to remove these 4 screws to get into it.

    Now as the fan was meant to run on a couple of batteries I thought I would try and preserve this, so that if needed the fan can be run on batteries if no usb ports are available, a word of caution, I wouldn't leave batteries in it when you run it from the usb ports.

    It's a good idea before you start wiring everything up to think about where the cable is going to exit the fan, so seeing as the fan you use will be different then where you put the hole for the cable is up to you, luckily mine already had one, this is most likely because it was meant to have a cable, or whoever made it used some standard components they got from somewhere, making the hole should be easy with a drill bit the same size as the usb cable.
    guess what ? it's picture time again.

    Here it is
    Cable entry hole.

    Once you are into the fan you need to find out how it's wired up, if your fan has a switch (which is a good idea, so if you can get one that has a switch, or you can put one in yourself) when I looked inside mine it had a sliding switch, basically a piece of metal attached to a plastic slide, so pretty simple.

    Yes you guessed it, another picture :-)

    The switch.

    As you can see the way the switch works is just by contacting one of the battery terminals, so this is where I decided to solder my wires, this way the wiring doesn't get in the way of the battery terminals, and the fan will run on batteries and usb.

    So with soldering iron in hand I set about attaching the wires, now I tend to solder everything I do like this,and I would recommend getting an iron if you don't have one, I have 3 2 gas powered (they use butane, the same stuff you put in cigarette lighters) and a standard electric one, either type is fine, and you can bug them from loads of places, here's some on Amazon as you can see they are pretty cheap, and very handy for jobs like this. You can just twist the wires from the usb lead onto the terminals, but there's a good chance that the connection won't be that good and movement my make the wires come loose, so I recommend soldering the wires on. 

    Picture time :-)
    Soldering the terminals.
    As it says on the picture, make sure you get the wiring right, otherwise the fan will run backwards, the motors in these are pretty simple, so it shouldn't hurt if you do get it wrong, but you don't want to run the thing backwards anyway. I then placed a piece of insulation tape over the usb lead to hold it in place, then I put it all back together, and that was it, it took about 10 minutes to do and now I can keep cool while I'm messing around on my pc :-)


    Okay some things to note, the usb voltage is about 5v give or take and the motors in these little fans are about 3 volts give or take, so they will spin pretty quickly and as a result they will be a touch noisy for some people, it doesn't make a difference to me, I have kids and they normally drown out any noise with their own.
    Also if you are worried about hurting your motherboard (this is what the usb ports are connected to) It should be okay, the first one I tried, the prototype if you like died on me (the motor was dodgy) and it hasn't hurt my system.

    Other things to think about, ways to improve the fan ? well you could adapt the usb lead method to make it more portable, this way it will have a lead, but if you wire up a usb port to the fan, so that you can just plug the lead in when you are at your desktop, and when you want the fan else where you just unplug and use batteries, I'm talking about a port kind of like you get in mp3 players and digital cameras, these should be easy to fit into the plastic casing.

    Hopefully you have found this useful ? and the other things I have planned to put on here, I don't drive so I use a bicycle to get about, this is okay, but you can't really carry much, so I built a trailer for mine out of some bits and pieces, I am making some plans to put on the blog for others to look at and maybe get inspired by. I have loads of other ideas and small projects as well, which people may find useful.

    Thanks for reading.







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