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stepper motor mount — Parallax Forums

stepper motor mount

JavalinJavalin Posts: 892
edited 2006-01-14 16:07 in General Discussion
Evening all,

Quick question.· Mounting stepper motors, obviously use the screws holes in the case to attach to the robot. But, how to you attach a wheel or similar to the shaft.· As far as I can see its not tappered (where it has a straight bit).

Also, am I correct in that you can drive a stepper motor to a fixed position repeatedly?· I.e. for a camera mount could you say power one pair of wires and it would jump to position X, or do you have to cause it to rotate and assume the angle?

Cheers

James

Comments

  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-01-12 20:54
    A stepper motor has only a fixed number of positions (deg./step).

    If you need to know that it's at some particular position then you'd make a "home sensor." (step, check, step, check,...)

    Shaft couplers (collets, set-screws.)


    Post Edited (PJ Allen) : 1/12/2006 8:58:12 PM GMT
  • JavalinJavalin Posts: 892
    edited 2006-01-12 21:02
    PJ,

    Thanks for the info!!

    james
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-01-12 23:17
    http://www.jameco.com/webapp/wcs/stores/servlet/CatalogSearchResultView?langId=-1&storeId=10001&catalogId=10001&searchType=k&searchValue=spider&categoryId=754015
  • JavalinJavalin Posts: 892
    edited 2006-01-13 10:37
    PJ,

    Thanks.

    James
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-01-14 15:06
    Connecting to a stepper motor shaft is an interesting question.

    For direct drive to a wheel, I have just kept the exisiting gear on and hot-glued the whell to the gear.
    I did drill a hole in the wheel hub that was the same size as the motor shaft. This elimanated any centering problems.

    If you have a blank shaft, much is dependent on size.

    The smallest of size seem to do best with a collet that fully grips their outside surface. These can be found in hobby airplane motor supplies as they adapt the shaft to a nut/bolt arrangement for various propellers.

    A bit larger shafts use a hub and set screw to connect a wheel. In this case, the torque of the motor is entirely dependent on the grip of one or two set screws. Often filing a flat side to the shaft will assure both a better grip and easier removal after the set screw digs a dimple into the shaft.

    Going up the scale, you begin to have shafts with a keyway and a square 'shear pin' in order to fully transfer the torque of powerful motors and to assure no eventual slippage or failure.

    Sadly, I don't know how to remove this messy crossout.·

    HELP!!!

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    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 1/14/2006 3:10:17 PM GMT
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2006-01-14 16:07
    Big K.,
    Kramer said...
    Sadly, I don't know how to remove this messy crossout.·
    · Doesn't the cross-out revert by high-lighting the crossed-out text and pressing the cross-out button?· Werx for me.
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