Build Your Own Magnetic Levitator

Here’s a great magnetic levitator build. [Scott Harden] dug up the link after seeing that awesome rotating globe this morning. This version hangs objects below an electromagnet but it has a sensor system to provide a constant distance between magnet and object even if the payloads are a different weight. This is done with a couple of infrared sensors. One acts as a reference detector, always viewing an IR LED in order to get a baseline measurement. That measurement is compared to a second detector mounted slightly lower. The circuit adjusts the electromagnetic field, making sure the object is always breaking the lower beam but never interrupting the reference beam. No microcontroller needed, this is handled with a couple of OpAmps. See it in action after the break.


34 thoughts on “Build Your Own Magnetic Levitator

  1. I actually have some of those ratiometric hall effect sensors on order from mouser as I was planning to do something like this soon. I was worried optical sensors might be more difficult to implement, but now I think I had it backwards. Very nice hack.

  2. i was looking into using op-amps to build a PID controller of sorts for this kind of thing, but maybe that would have been overkill… this is pretty sweet. next step: put a small AC signal through the coil to measure a drift in inductance? then you wouldn’t need any external sensors at all, right?

    1. @Spork,
      Though we do delete comments that are offensive or completely off topic, I don’t show any other comments from your IP since the 26th. None in the trash, none in the spam box. I don’t know what happened to your comment.

  3. Yay I contributed to hackaday! I saw this hack and thought it was awesome hacker spirit. I especially love how it’s all made from crap lying around the house. Legos, nuts, wood from a dumpster probably! The only thing cooler would be a LED blinking on and off, which could be accomplished by adding an Arduino… [/evil]

  4. I have an (fairly obvious) idea how to extend this into even more awesomeness:

    1) make two coils and use them to move object from beneath one coil to beneath the other coil, and back again.

    2) Make several coils in line and use them to zip levitating object from one end of the “path” to another and back.

    3) Make a circular path and … you get the idea, basically a magnetic merry-go-round (like a stepper motor)!

  5. I did this exact same project (seriously, identical) for a lab in a college Feedback and Control class. It worked surprisingly well once I tweaked it a little. You could touch the object a little and cause it to oscillate back and forth for awhile inside of the “sweet spot”. It was also fun to rotate the object and see how long it would keep spinning.

  6. or you could gut a few dead 5 1/4″ floppy drives, also some toshiba vcrs (now useless after the switchover) have three linear hall sensors with +/- gauss outputs under the capstan motor and another on the drum motor..

    another worthwhile place if you can solder smd is any old brushless motor from an ODD, these use 4 pin variations on the toshiba sensors.

    for rotation sensors look in old cd changers, they use them in the drive to locate the number of steps moved and look like an 8 pin SOIC.

  7. This is great, but how about this???
    How big would the coil have to be to levitate… say a 150 pound human?

    That human would be wearing a harness strapped to a helmet contraption. The helmet would be covered with rare earth (hard drive) magnets of course.

    This sounds very possible.

    And the real question is, what would it feel like?
    Would you feel weightless?

    I’m kind of joking, but not really. :)

    I’m sure someone here could suspend a human easily with a large enough coil.

  8. Would be neat to levitate a person, or something much larger. But lets hope the person doesnt have any piercings or electronic implants of any form, pacemaker, defib box. You get the idea.

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