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80-Cent Micro Gearmotors — Parallax Forums

80-Cent Micro Gearmotors

ercoerco Posts: 20,244
This seller is accepting 80-cent offers for these cute little gearmotors: http://www.ebay.com/itm/112314392085

Same diameter as an LR44 watch battery, they are designed to accept a single 357 battery, friction fits nicely in place. 9 mA no load at 1.5V means that in a pinch, you could carefully drive this directly from micro output pins with a few dropping diodes.

Comments

  • Buy a bunch, and if they last longer than a few minutes, we'll buy them from you.

    Signed, Mr. Lemming.
  • ercoerco Posts: 20,244
    Buy a bunch, and if they last longer than a few minutes, we'll buy them from you.

    $8.50 at ercoshop.con, I mean com.

  • Cluso99Cluso99 Posts: 18,066
    You could probably drive direct from a pair of prop pins, maybe with a small resistor to limit the start current. That way you could reverse too.
  • ercoerco Posts: 20,244
    Yup, two pins=poor man's H-bridge.
  • Cluso99 wrote:
    ... maybe with a small resistor to limit the start current. ...
    I'd be more concerned about the stall current than about the start current. Since the motor presents an inductive load, start current should be less than running current.

    -Phil
  • ercoerco Posts: 20,244
    Since the motor presents an inductive load, start current should be less than running current.

    Surely you jest, good sir.
  • Cluso99Cluso99 Posts: 18,066
    Cluso99 wrote:
    ... maybe with a small resistor to limit the start current. ...
    I'd be more concerned about the stall current than about the start current. Since the motor presents an inductive load, start current should be less than running current.

    -Phil
    That's why the old disc drivestook 40A to start and 8A once running ???
  • I guess I'm confusing DC motors with steppers. When you stop to think about it, with a DC motor, the starting current and stall current are probably pretty much the same. IOW, a motor that's first powered up (i.e. not turning) is the same as one that's stalled (i.e. not turning). :)

    -Phil
  • ercoerco Posts: 20,244
    See? You were testing us to see who's paying atttention. That was Saturday quiz #1!
  • ercoerco Posts: 20,244
    "These $2.66 metal gearmotors are also quite the dealio", said Uncle Rico to Napoleon Dynamite.

    http://www.ebay.com/itm/172367169254

    s-l1600.jpg



  • erco wrote: »
    "These $2.66 metal gearmotors are also quite the dealio"

    How many are you getting?

    How many do I need?

    Why do I need them?

    I have a feeling I need them but I'm having trouble figuring out why.

  • ercoerco Posts: 20,244
    Received two yesterday and tested, just ordered 4 more.

    Just order six and thank me later, Boss!
  • I wonder if the Pololu motor mounts (for their very similar/identical motors) fit this. With no mounting flange or holes of their own, it's down to strapping these puppies in.

    Give us the low-down when you've fully tested these. Be sure to use the new TPS report cover.
  • ercoerco Posts: 20,244
    With no mounting flange or holes of their own, it's down to strapping these puppies in.

    Bolts & straps, you're so funny when you pretend like you don't know about super glue!



  • ercoerco Posts: 20,244
    Another cheap new find is this $1.76 94:1 DC gearmotor: http://www.ebay.com/itm//252784806399

    Bigger, noisier and cheaper than some 48:1 gearboxes, but they have a few advantages. Twice the torque (half the speed) and the flatted steel shaft slides through and is easier to connect random things to.

    I make ~60-70 RPM with good torque at 1.5V. Worth hoarding ordering 4 units IMHO.

    s-l1600.jpg

    motors.jpg
    1920 x 2560 - 1023K
    motors.jpg 1022.9K
  • erco wrote: »
    With no mounting flange or holes of their own, it's down to strapping these puppies in.

    Bolts & straps, you're so funny when you pretend like you don't know about super glue!

    Well there's home brew and there's pro brewski. One you don't mind sharing with friends, the other you bring out when you're trying to impress someone.

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