magnets!

Discussion in 'The Projects Forum' started by capnray, Sep 6, 2011.

  1. capnray

    Thread Starter Member

    Jul 3, 2010
    59
    2
    I have a project using Hall Effect sensors, I have been unable to find magnets suitable for the design. I would like the diameter to be .25", thickness <.25" and the magnetic density in the neighborhood of 300 - 1000 gauss. Digikwey has the size in 10800 gauss, not acceptable. any help is greatly appreciated.
     
  2. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Have a look on ebay, there are a few sellers with good selections.
     
  3. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
  4. ElectroDFW

    New Member

    Sep 2, 2011
    15
    1
    No info on the gauss strength, but Harbor Freight has 10 piece Rare-Earth Magnets 5/16 x 1/8", Item #67488

    Also, the magnets found in audio/mp3 earbuds sure seem strong to me...and tiny to boot.

    Regards,
    --Electro--
    aka David M
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,145
    3,055
    Menards often gives away (after rebate) magnetic tool-holder armbands, and these contain a number of powerful disk magnets.
     
  6. vrainom

    Member

    Sep 8, 2011
    109
    19
    http://www.dealextreme.com/p/super-strong-rare-earth-re-magnets-8mm-20-pack-4248 I have bought some of these a couple of times, supposedly made of neodymium. They are quite strong but since they are thinner I suppose they should be milder that the ones at digikey; I haven`t made measurements though. Still at that price it's great value.

    Also you've got to take into account that the measured magnetic flux density is affected by angle, distance and temperature so if you want to use a hall effect sensor to determine the distance of an object, just put it further apart and it'll do the trick
     
    Last edited: Sep 11, 2011
  7. capnray

    Thread Starter Member

    Jul 3, 2010
    59
    2
    Thanks, am trying every magnet I see.
     
  8. capnray

    Thread Starter Member

    Jul 3, 2010
    59
    2
    I used Hall devices in the mid '80's, know the "quirks", thanks for the reminder
     
    Last edited: Sep 16, 2011
  9. capnray

    Thread Starter Member

    Jul 3, 2010
    59
    2
    I checked out the site and the magnet offer. Since they are neodymium I suspect they are very strong. A footnote concerning packaging has me ordering 100 with no shipping charge, the price cannot be beat, thanks again. I need south poles for shaft speed, north poles can be used interposed to regen the battery.
     
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