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Floating/Rotation above computer fan

  1. Oct 5, 2012 #1
    I made this video a while back:

    The black box is a bitcoin miner (irrelevant) with a fan that blows upwards just underneath the holes.
    I was trying to make the piece of paper float. I think this should be possible since the air velocity is higher on the outsides of the fan than in the center. I seem to recall air "guns" that could float a light-weight ball in the air.

    Is that actually possible or am I overlooking something?
    Last edited by a moderator: Sep 25, 2014
  2. jcsd
  3. Oct 5, 2012 #2


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    or a better looking version..
    Last edited by a moderator: Sep 25, 2014
  4. Oct 5, 2012 #3


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    Staff: Mentor

    Welcome to PF!

    Why would you think the velocity would be higher on the outside
  5. Oct 5, 2012 #4
    Thanks :)
    The center of the fan is where the actuator is located, which means there's a column in the center that's not blown on directly. Perhaps the air there will still move due to a drag effect, but I don't know how strong that effect would be.
  6. Oct 6, 2012 #5
    I never knew people did bitcon on their OWN hardware.

    *cough* think about that the next time your CPU load spikes on a webpage with odd banner adverts :-)
  7. Oct 6, 2012 #6
    Haha, although I can't deny that there are probably botnets mining Bitcoin, the large majority is actually people's own hardware. The main reason for this is that mining on a CPU is simply practically useless. GPUs are about a factor 100 faster at it, and botnets tend not to have very fancy GPUs.
    The hardware shown in the picture is an FPGA (Field programmable gate array) miner, which is about a factor 5 faster than GPUs. Then there have been at least a million USD in preorders for ASIC miners, which are, again, a factor 10 better than FPGAs. They're due to be shipped somewhere in the next few months. Soon running a botnet for Bitcoin won't even be worth finding bots for.
  8. Oct 6, 2012 #7
    I bought some for experimentation ages back when they were sub $1 then sold them when they went up. I haven't been back into bitcoin. It's going to be huge one day though.

    Are those FPGA boxes what the bank R&D boys are using? I know some of them are looking at bitcoin.
  9. Oct 6, 2012 #8
    I don't know any bank people that are actively mining. In fact, banks and such are only starting to get interested now.

    But as for people who have huge amounts of mining power, yes, the FPGAs are what is most commonly used at the moment along with GPUs. "The masses" still use only GPUs since they have those in their computer anyway.
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