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I was just hanging out at Al Lasher’s Electronics in Berkeley when the proprietor Bob showed me this little gizmo. It’s the creation of one of his customers and is definitely the simplest DC motor I’ve ever seen. An AA battery sits on top of a couple neodymium magnet, and a coil of wire balances on top of the positive pole of the battery. Once it’s set up the motor spins right up.

I can’t think of a motor that’s more simple and elegant than this one. Can you?

Michael Colombo

In addition to being an online editor for MAKE Magazine, Michael Colombo works in fabrication, electronics, sound design, music production and performance (Yes. All that.) In the past he has also been a childrens’ educator and entertainer, and holds a Masters degree from NYU’s Interactive Telecommunications Program.


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Comments

    1. Ahh super cool! And the same basic design. Thanks for posting.

  1. robtsou says:

    These are definitely fun to make and watch but since you’re shorting the battery terminals, be careful they don’t overheat.

    1. sparky3489 says:

      That’s the beauty of them, it’s not shorting the battery directly if it’s made right. It is only making brief contact with a random duty cycle,.

  2. John Gale says:

    I like this magnetohydrodynamic “salt and pepper motor” because you can demo it in a pub, if you happen to be carrying an AA battery and a neodymium button magnet: http://www.evilmadscientist.com/2006/mhd-i-demonstrate-magnetohydrodynamic-propulsion-in-a-minute/

  3. jon says:

    Somebody didn’t do a Google search before writing/posting an article… (or even do a MakeZine.com search!). Come on guys.

    By the way, you should do an article on this cool toy I saw where you attach a vibrating motor to a toothbrush head! Who would have thought it could be such fun? It’s crazy !

    1. Au contraire. I did, in fact, do a search for simple DC motors before putting this post up. The only one that is similar to the one I posted is the one linked to by sparky3489. And do you see the “related” section under the post? Those are hand-picked by the authors – I found other examples of simple DC motors that MAKE has covered and they’re not like the one I posted.

      1. I think Jon is referring to several posts you can find if you search for ‘homopolar’, which is the type of motor this is.
        It’s really funny that I just showed this design to some kids at the local children’s museum the other day, and then it resurfaced on MAKE. Thanks for posting. I made one as a desk toy and it is turning and bumping away right now. I like the sound of it as well as the motion.
        I use it to run down AAA batteries that are already too weak to be of much use before I dispose of them. You can stack up several neodymium magnets to make the motor more effective.

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