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Hard Drive Stepper Motor - with high speed spin-up circuit - Page 2 — Parallax Forums

Hard Drive Stepper Motor - with high speed spin-up circuit



  • Heater,
    Are you thinking of something like this project?
    It uses reaction forces, but the idea is similar;
  • Heater.Heater. Posts: 21,230
    I love the reaction wheel idea but that is not what I had in mind. That is a beautiful demonstration by the way.

    What I was thinking was to make the actual giro sensor out of a spinning hard drive motor and it's platters. Twist a spinning disk around an axis at right angles to it's axis of spin and it will produce a torque reaction about the axis perpendicular to both of those. So we only need to mount the thing on a "hinge" and confine it's movement with springs. Then the rate of twist will produce a proportional movement against those springs. We can measure that with some inductive motion sensor or even just a pot.

    That is how gyros were made before we had MEMS chips to do it for us. See this nice model helicopter gyro picture:

    It is actually a very different idea. The spinning masses are the sensor not the actuator.
  • Heater,
    OK, I get it.
    In that inverted pendulum spike project you could have the spinning gyroscope acting as the motion sensor to control the reaction wheels.
    At the moment the motion sensor is an IMU chip.
    Pretty cool, 3 spinning wheels on a spike!
  • This is a nice toy.
    307 x 500 - 17K
  • Heater.Heater. Posts: 21,230
    This an even better toy:


    Bit spendy but I want one.
  • TorTor Posts: 2,010
    Nice. I want one too.
  • Heater.Heater. Posts: 21,230
    Yes, and the motor and gimble kits for it. Might have to be my Christmas present to myself.
  • MikeDYurMikeDYur Posts: 2,176
    edited 2016-10-29 13:02
    Heater. wrote: »
    This an even better toy:

    I want one too, but haven't checked the price yet.

    EDIT: 85 pounds sterling, sounds pricey without knowing the conversion. Hook that up to a brushless hard disc motor, may go for over an hour.
  • Heater.Heater. Posts: 21,230
    Yeah but they already have a motor add on for it that connects to it neatly.

    I want it all !

  • I came up with $70.00 US, and that seems quite reasonable for a precision instrument.
  • TorTor Posts: 2,010
    Start it, remove the little motor, it runs for 25 minutes. That's not cheaply made..
  • User NameUser Name Posts: 1,451
    edited 2016-10-30 03:50
    @MikeDYur: The US price is $88.99. For some reason (no VAT?) they're giving gringos a break, because £85 is $103.62 atm.

  • MikeDYurMikeDYur Posts: 2,176
    edited 2016-10-30 12:18
    User Name wrote: »
    @MikeDYur: The US price is $88.99. For some reason (no VAT?) they're giving gringos a break, because £85 is $103.62 atm.

    Thanks for the correction, I got my info from a Google app. Still a good price for a quality product.
  • I pulled this from an old HD, and I'm not sure how the motor was applied now. But the weight of the platters combined with significant speed would make a decent gyroscope. Manufacturers put a lot of expence in the blossoming technology.
    1280 x 720 - 442K
    1280 x 720 - 369K
    1280 x 720 - 270K
    1280 x 720 - 310K
  • garagengineer65garagengineer65 Posts: 1
    edited 2022-08-31 13:39

    Hi All,

    I built this circuit in 2016, here's a video of it working:-

    I actually removed 2n3906 and 2n3904 transistors, and put a 10k variable resistor on the gate of the mosfet to output pin 6 on 741 op amp, to control the speed, works a treat.

    recently I have gotten back into project building and found a use for the cct, there are other ways to spin hdd motors but i think this cct is still neat
    here are some latest pics:-


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