Magneticaly Levitated Turntable Platform.

Discussion in 'Home Theater Projects' started by Brett DiMichele, Apr 5, 2003.

  1. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    I was sitting here thinking (as always when I do this I get
    myself into trouble but not before I smell smoke..)

    I have a bunch of very strong magnets that are a hair under
    1/2" Diameter I belive they are Alnico possibly Strontium.
    Whatever they are they are super smooth and extremely strong.

    As an example of how strong they are it takes everything I
    have just to pull 2 of them apart and it feels like it takes
    about 7 pounds worth of force to push them togeter.

    So I was thinking why not install 8 of these into 2 simple
    pieces of MDF and let magnetism float the upper platform.

    Seems like a simple and dirt cheap way to suspend a turn
    table or even a CD Player forget "absorbing" vibration if
    it's floating in the air you don't have to deal with it at
    all [​IMG]
     
  2. Jeff Hoak

    Jeff Hoak Stunt Coordinator

    Joined:
    Jun 26, 2001
    Messages:
    137
    Likes Received:
    0
    Trophy Points:
    0
    Great idea except for one little problem. At least in terms of turntables magnetic fields are a bad thing. You'd need to be able to shield or isolate the cartridge from any field generated by the magnets. I don't have any idea how easy (or difficult) that would be.

    As for using under a CD or other equipment it'd probably be fine so long as the equipment being "floated" isn't effected by magnetic fields.

    I actually played with the idea a couple of years ago. Getting the upper platform to float on the field was pretty easy. The hard part was alignment. In order to get the upper platform to be stable side to side and front to back I had to introduce mechanical connections that transmitted the very vibrations that I was trying to eliminate.

    I did ultimately figure out a way to maintain lateral alignment but it have required a bunch more magnets and I didn't at the time have access to any more.

    I was floating an 18" x 18" x 1" granite slab to use as a turntable base. I never did overcome the effects of the magnets on the phono cartridge. I considered a layer of some type of metal as shielding but abandoned the project before it got that far.

    I think that somewhere here I have my original notes and drawings if you're interested.
     
  3. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    Jeff,

    I appreciate your offer but it's just an idle experiment for
    me. My turntable is hardly anything high end so this is just
    an experiment with some scrap I have laying around the house.

    I was thinking the same thing about lateral alignments but
    there has to be a way to completely suspend it and align
    it with the magnets that are suspending the platform. The
    magnets have a natural set of poles and they always force'
    away from eachother's opposite poles so if you strategicaly
    apply the magnets they should essentialy try and force the
    table in all 4 directions thus ballancing eachother out.

    Wouldn't the opposing magnets cancel eachother out to where
    the fields wouldn't affect the item being suspended?

    I will give it a shot and see what happens.. Worst case
    scenario it doesn't work, I laugh and go back to pondering
    how to take over the world.. *noFf* [​IMG]
     
  4. Rich Kraus

    Rich Kraus Stunt Coordinator

    Joined:
    May 3, 2000
    Messages:
    209
    Likes Received:
    0
    Trophy Points:
    0
    seems to me that if you mounted the magnet pairs in all four corners on an angle it would make it self centering.

    bad keyboard art to explain:


    _________/

    _________/


    magnets in pairs on the slashes.

    did that make sence?
     
  5. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    Rich,

    Makes perfect sense I will have to try that..

    I cut two small pieces of MDF and drilled 1/2" holes in
    each corner the magnets fit perfectly in the holes.

    But alas I get the same problem Jeff experianced it wants
    to push off to the side.. I will try your suggestion.

    It seems pointless to me to make a levitation device and
    then have to rely on pins to locate the thing and therfore
    transfer the very vibrations you are trying to eliminate.

    Magnetism bites.. Why can't they have 4 poles [​IMG]

    Then Hoverboards could be a reality! (Woah BTTFII Flashback)

    [​IMG]
     
  6. ChristopherW

    ChristopherW Agent

    Joined:
    May 23, 2002
    Messages:
    36
    Likes Received:
    0
    Trophy Points:
    0
    Hey guys,

    This link my give you guys some ideas on your designs. I think this is similar to what you guys are trying to do. Let us know how it turns out!

    http://gr-research.com/levitator.htm

    Chris
     
  7. John Wes

    John Wes Stunt Coordinator

    Joined:
    Nov 23, 2002
    Messages:
    202
    Likes Received:
    0
    Trophy Points:
    0
     
  8. Frank Carter

    Frank Carter Screenwriter

    Joined:
    Mar 12, 2002
    Messages:
    1,187
    Likes Received:
    0
    Trophy Points:
    0
    If you visit the psaudio.com, go to toolbox, then tips & tricks, someone described the process they went through to do the same thing.
     
  9. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    Chris,

    Yes the Levitator is what I am trying to copy it seems a
    tad pricey to me.. [​IMG]

    Frank,

    Thanks for the linkage I am checking it out!
     
  10. Danny Richie

    Danny Richie Stunt Coordinator

    Joined:
    Apr 8, 2002
    Messages:
    171
    Likes Received:
    0
    Trophy Points:
    0
    For what it is worth.

    The opposing magnets cancel one anothers fields.

    You can set a Levitator right on top of a TV with no effect to the picture.

    The guide pins used to keep it aligned are not solidly locking the two platforms together. It floats on those as well, and it transmits very little from the bottom to the top from that contact.

    As for the price: The high powered Neo magnets are not cheap. The polished Acrylic top plate is not cheap either.

    There is another company in Italy that makes one similar to the Levitator that is also available in the US but it is $150. more, and its aligning mechanism does solidly lock the top and bottom plates together (transmitting more resonances).

    Compared to other mass loading systems the Levitator is cheap.

    But hey, if you can DIY your own have at it, and have fun.
     
  11. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    Danny,

    Thanks for the post!

    I realise that the Arcrylic isn't cheap I have worked with
    very thick pieces in the past and I know that 19" or so
    piece probably costs Dodd Audio $150.00 unless they are
    buying in real huge bulk alotments and even then there is
    not a whole lot of discount.

    The magnets are not that expensive you can order Neo 1/2
    magnets from some of the large machine trades catalogs for
    about 3 dollars each and the MDF isn't that expensive.

    I bought 12 Alnico's for a buck each (I think they are
    Alnico.. I dunno they are super smooth finish all around so
    they may be Neo I am not certain) but I do know they support
    a ton of weight. I tried out a small levitation platform
    yesterday (about 5" squared) with 4 magnets per piece of
    MDF and it supports my small Iron Anvil (7 or 10 pounds)
    with ease.

    I guess there is no way around it I will have to use 2
    locating pins but I will keep them as free floating as
    possible and yes the magnets cancel eachother out.
     
  12. Hank Frankenberg

    Hank Frankenberg Cinematographer

    Joined:
    Oct 13, 1998
    Messages:
    2,573
    Likes Received:
    0
    Trophy Points:
    0
    Brett, I recommend you use neodymium magnets for their strength. One souce I found is Bunting Magnetics. They've got an enormous quantity of magnetic products. Here's their neodymium listing:
    http://www.bunting-magnetics.com/rou...ID=mapinfo.htm
    The prices are for one each. I ordered a quantity of 1/4" x 14" nickel-plated neos and the net price each was almost half the one each price. Their tech help can probably recommend magnet strengths based on your load-carrying requirements.

    Buy enough magnets and you can go onstage as a magician and do body "levitating" tricks[​IMG]
     
  13. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    LOL Hank

    Thanks for the link [​IMG]
     
  14. Chris Carswell

    Chris Carswell Supporting Actor

    Joined:
    Mar 5, 2002
    Messages:
    598
    Likes Received:
    0
    Trophy Points:
    0
    Hank or anyone else who can answer this one. Looking at the Bunting Magnetics web page they have listed the Holding Force (in lbs.) for each magnet. If one magnet has a 20 lb holding force any idea what it's apposing force would be?(wt. required to push them together) Would it be close to the same weight???
     
  15. Jeff Braddock

    Jeff Braddock Second Unit

    Joined:
    Jan 26, 2002
    Messages:
    306
    Likes Received:
    0
    Trophy Points:
    0
    Brett or anybody else, could you use a few short lengths of string to keep the levitated platform in place? The way I am picturing it in my mind is attatching like 4 peices of string to the base on the edges and have them connected to the levitated platform on the edges. You wouldn't be able to have much if any slack, but I would think it would keep it centered with minimal vibration conduction. I don't have any idea if it would work, but tell me what you think.
     
  16. Brett DiMichele

    Brett DiMichele Producer

    Joined:
    Sep 30, 2001
    Messages:
    3,181
    Likes Received:
    0
    Trophy Points:
    0
    Jeff,

    It would be nice if that could work but the force of the
    magnets will push it off to one side. My test piece I used
    screws down through the top plate *free floating* and the
    holes have a little bit of slack to them and it still goes
    off kilter.. A precision machine process would make a much
    better final product.. Making the bottom out of 1/2" thick
    aluminum with 4 micron surface finish pins sticking up into
    a piece of arcrylic would yeild a much smoother piece.

    Unfortunatly it's sad you have to have a physical connection
    as IMHO this negates the positives of magnetic levitation
    completely.

    But I have not given up, I am going to do lots of research
    and see what I can come up with.
     
  17. Jeff Braddock

    Jeff Braddock Second Unit

    Joined:
    Jan 26, 2002
    Messages:
    306
    Likes Received:
    0
    Trophy Points:
    0
    RE: pushing it off to one side, that is what the string would prevent I would think. Have a piece or two of string on each of the 4 sides with little to no slack should keep it from going off to one side or another. Maybe I'm not visualizing the situation correctly or something, but why wouldn't it work?

    Also Brett, did I ever send you that article on how to build your own heatpipe?
     
  18. Dean Cooper

    Dean Cooper Supporting Actor

    Joined:
    Oct 23, 2000
    Messages:
    972
    Likes Received:
    3
    Trophy Points:
    0
    The solution to keep the plates aligned is to have two sets of magnets that are attracting each other with either 4 or 6 opposing sets. The attracting magnets hold it in place while the others lift the plate. The best place to get neodymium magnets is believe it or not Ebay and a good cheap magnetic shield is a plate of stainless or aluminum. Have fun [​IMG]
     
  19. Lee Carbray

    Lee Carbray Second Unit

    Joined:
    Oct 23, 2002
    Messages:
    308
    Likes Received:
    0
    Trophy Points:
    0
    According to
    this It is impossible.

    My idea is simmilar to Rick Kraus's. Except instead of having the sides of the top plate at angles keep them as perpendicular and put sides on the base. Kind of like an open box. Use some magnets on the bottom of the top plate to levitate it. To stabalize it mount some on the sides of the open box as well as the sides of the top plate.

    Don't forget to patent it once you do the impossible.Mmmmm royalties.
     
  20. Danny Richie

    Danny Richie Stunt Coordinator

    Joined:
    Apr 8, 2002
    Messages:
    171
    Likes Received:
    0
    Trophy Points:
    0
    Gary Dodd did build one that did indeed levitate without any contacts at all.

    It did use attracting magnets for alignment and even more repelling magnets.

    He said it looked real cool but would be a major liability.

    If the weight that you placed on top was not centered or if you bumped it just a little to hard (not hard at all) it would throw that platform across the room, or twist in a way that would allow the attracting magnets to slam together with a force that would break fingers.

    The attracting magnets also gave off a really big magnetic field.

    I believe Gary tried many different possibilities before settling on the configuration used in the Levitator.
    I can't see any better options myself.
     

Share This Page