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  1. #1
    n00b
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    Looking for muffin fans...

    But NOT the typical 12VDC units. I'd like to find them in 5VDC or 6VDC - maybe 3VDC, but 5 or 6 will be easier for me to work with.

    I spend a lot of time in libraries, reference sections. They're usually stuffy. I want to make some small portable fans (so I don't have to carry that foot-tall tower job with me to plug in...) that I can make run on batteries or wall warts. I'm thinking that I'd probably put a rechargable battery in it, have positions for CR123As (which I use elsewhere - I buy those several dozen at a time from SureFire, the power density there is excellent!) and have a barrel plug to plug in a 5V or 6V wall wart, if the batteries are shot.

    I'd like to find something 3"-4" across - this will allow me to put it in a fairly small box (to hold the batteries and wiring as well,) but should still move enough air to matter. Doing the sheetmetal work/plastic work to customise the box is no trouble for me, neither is the hardware (or soldering, or wiring, or anything else.)

    I've just been getting stuck finding muffin fans that are:
    - A useful size (3-4" across)
    - Not 12VDC (6VDC preferred, 5VDC or 3/3.3VDC will be workable)
    - Run rather quiet (I do plan to use these in libraries. Most people may elect to make noise in libraries, but I'm too old for that &***)
    - And hopefully not overly damned spendy


    I'll be putting these into smallish boxen (I plan to make three or four of them,) and I'd like to keep the weight down as well (the electronics don't pose a problem, and nearly anything will be lighter than the tower fan I now carry around.)

    This is a project I want to tackle before I buy/build a cellphone jammer (I don't understand why people can't read the signs - what part of "Put your cellphone on silent or turn it off" is so difficult to understand? I figure either a jammer to knock the calls off the air, or a HERF gun to just smoke the phone...)

    Any ideas?

  2. #2
    n00b unixdude's Avatar
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    check out digikey ; I found http://search.digikey.com/us/en/prod...CR043-ND/42793 ;

    I understand you're trying to minimize noise and maximize battery life - might be more difficult than you think. The above fan is low noise, compared to others they sell, but only runs 2.2 watts @ 12v. The spec's show it will accept 6 - 12v and only 0.180a's.
    -unixdude
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  3. #3
    Administrator TDSP's Avatar
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    If you are wanting 3-4 inches across, I'd almost go with a "silent", low RPM bathroom ventilator fan from a hardware store. If you are gonna be carrying this thing around, a squirrel cage might work out better anyway. They put out about the same CFM as a car vent and will run off an incredibly small amount of juice (though it's typically A/C). You can also use a simple TRIAC rheostat to control speed that way...

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  4. #4
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    Quote Originally Posted by unixdude View Post
    check out digikey ; I found http://search.digikey.com/us/en/prod...CR043-ND/42793 ;

    I understand you're trying to minimize noise and maximize battery life - might be more difficult than you think. The above fan is low noise, compared to others they sell, but only runs 2.2 watts @ 12v. The spec's show it will accept 6 - 12v and only 0.180a's.
    I am more concerned with reducing noise than with extending battery life - I plan on designing the thing to be flexible for power needs (one-shot cells, rechargables, wall wart.)

    The idea being reducing voltage was to reduce battery mass - not so much to reduce battery life. Battery life isn't as critical for this application, simply because I plan to use this thing in civilisation - it's not "mission critical" and going to be used out where endurance and weight are critical factors.

    I simply wanted to keep the voltage requirement low because this thing will be carried about in an "office bag" - I didn't want it to take up too much space - and that allows me to reduce battery bulk (and, therefore, package size.)

    Does this make more sense?

    As far as going with an AC squirrel cage - I don't always have AC power available when I'm working (not all libraries run AC power to the work tables,) which is why I wanted to stick with DC power insofar as possible.

    WRT air volume - I don't need a great deal, I'm not trying to feed an engine or an air compressor. I simply want more local air circulation - I have chronic sinus problems (that are improved with circulated air!) and my wife - who tries to help me from time to time - is asthmatic and sensitive to "stale air."

    - ON/OFF modes are fine.
    - If I have to pillage around to figure out a decent 12V setup, fine - but I do prefer lower voltage for reasons stated.
    - I'd like this to be as self-contained as possible. It's useful to be able to plug in a wall wart to make it work, but if I don't have power I want to be able to pull this out of my bag and switch it on - problem solved.
    - Since we're using these in libraries, we're obviously doing paperwork. A "hurricane" fan isn't needed with paper - I'd like to keep my work on the table! It's just circulating air to help us work.

    I honestly didn't think very many 12VDC fans would provide useful airflow with reduced voltage input - if they do, that brings them back up as an option. I'll have to check out the datasheets on that Digi-Key fan in a bit. Are those prices per each, or for a quantity box, tho? I only need three or four of the things...

  5. #5
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    Quote Originally Posted by unixdude View Post
    check out digikey ; I found http://search.digikey.com/us/en/prod...CR043-ND/42793 ;

    I understand you're trying to minimize noise and maximize battery life - might be more difficult than you think. The above fan is low noise, compared to others they sell, but only runs 2.2 watts @ 12v. The spec's show it will accept 6 - 12v and only 0.180a's.
    I am more concerned with reducing noise than with extending battery life - I plan on designing the thing to be flexible for power needs (one-shot cells, rechargables, wall wart.)

    The idea being reducing voltage was to reduce battery mass - not so much to reduce battery life. Battery life isn't as critical for this application, simply because I plan to use this thing in civilisation - it's not "mission critical" and going to be used out where endurance and weight are critical factors.

    I simply wanted to keep the voltage requirement low because this thing will be carried about in an "office bag" - I didn't want it to take up too much space - and that allows me to reduce battery bulk (and, therefore, package size.)

    Does this make more sense?

    As far as going with an AC squirrel cage - I don't always have AC power available when I'm working (not all libraries run AC power to the work tables,) which is why I wanted to stick with DC power insofar as possible.

    WRT air volume - I don't need a great deal, I'm not trying to feed an engine or an air compressor. I simply want more local air circulation - I have chronic sinus problems (that are improved with circulated air!) and my wife - who tries to help me from time to time - is asthmatic and sensitive to "stale air."

    - ON/OFF modes are fine.
    - If I have to pillage around to figure out a decent 12V setup, fine - but I do prefer lower voltage for reasons stated.
    - I'd like this to be as self-contained as possible. It's useful to be able to plug in a wall wart to make it work, but if I don't have power I want to be able to pull this out of my bag and switch it on - problem solved.
    - Since we're using these in libraries, we're obviously doing paperwork. A "hurricane" fan isn't needed with paper - I'd like to keep my work on the table! It's just circulating air to help us work.

    I honestly didn't think very many 12VDC fans would provide useful airflow with reduced voltage input - if they do, that brings them back up as an option. I'll have to check out the datasheets on that Digi-Key fan in a bit. Are those prices per each, or for a quantity box, tho? I only need three or four of the things...

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