Electric longboard uses DIY hub motors

As a student of MIT, [Jed Storey] has access to a ton of machine tools, so he decided to build an electric longboard with hub motors by hand.  He wound up re-doing a lot of his project, so we can commiserate with him on the trials of R&D.

Inspired by the BWD scooter, [Jed]‘s longboard uses hub motors – the wheel is the motor. The rotors were fabricated in-house, and off-the-shelf stators were wound by [Jed] by hand. There’s a lot of work that went into this build, and the build log is really fascinating in this regard.

The board is controlled by a pistol-grip R/C controller that had been modified to include a dev board and an XBee. For power, an aluminum enclosure was fabricated, strapped underneath the deck, and filled with LiPo batteries. While the build is mostly done, [Jeb] is thinking about scrapping it and moving onto version 2, the HeavyBoard. Check out the video of the board in action.

Comments

  1. Alex says:

    Very cool, but I sure hope they can get it going faster when they take it outside.

    • Jamo says:

      That will be no issue at all. Calculations from back EMF show a top speed of 30mph. After mechanical losses hes still getting 15-20 mph, which is still tons faster than I would like to go on a hands free EV ;)

      He has some great pictures in his build logs. Good work Jed!

  2. vasskk says:

    Looks like the batteries hit the ground if you try to lean into corners…

  3. APE says:

    First link=404.

  4. Too Freaking Cool! Wish I could have gone to MIT ;-)

  5. Wotan says:

    Awesome. A little bit high apparent turn radius, but based on the fact that the board is 4WD I suppose that differential steering is included in the short term to do list..

    /W

  6. MyL177l3Pwny says:

    Been working on something similar off and on for the past year. Never even thought of how it would affect the turn rate. Well back to the drawing board.

  7. crow1170 says:

    I know the intent of this project was probably to have a powered ride, but I think the real advantage here is “Accio Longboard!!”

  8. Jed Storey says:

    The turning radius is not affected by the fact that it is 4WD. The controllers use current control, so the motors automatically adjust their RPM in turns (outside wheels spin faster, inside wheels slower). It’s sorta like an electronic differential.

    The reason the turning radius sucks is because I used over an inch of soft rubber riser pads that don’t transfer the leaning torque into rotating the trucks…plus they are ancient MBS trucks, and are in pretty poor shape (they were what I had on hand when I was designing it).

  9. KillerBug says:

    Sounds like you have more custom fabrication to do…good thing you have all those pretty machine tools!

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