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Wire/ribbon "Muscle" — Parallax Forums

Wire/ribbon "Muscle"

John R.John R. Posts: 1,376
edited 2005-12-24 05:06 in General Discussion
I've tried googling, and come up with everything but what I'm after.

Some years ago (over 10), I saw a wire or ribbon device that could be purchased on a "spool".· This "stuff" acted like a muscle, in that when you passed current through it, it would contract.· The more current (or voltage, don't remember which), the more it would contract.·

The application I saw this stuff on was to rock a "IR motion sensor" back and forth on a pivot so that it could see "stationary" people.· (by moving the sensor, the people seemed to be moving)· This was used as part of a "safety curtain" to make sure people were not in the way of a moving device.

Has anybody else seen this stuff?· More importantly, does anyone know what it is really called, and/or where I can get some?

Thanks;


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John R.

8 + 8 = 10

Comments

  • Paul K.Paul K. Posts: 150
    edited 2005-12-23 15:47
    I believe the stuff is called flexinol and Nitinol

    Paul
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-12-23 15:47
    Its called muscle wire (formally know as shape memory alloys (SMA)) (variations of it are Flexinol, Biometal, and Nitinol) and the main distributor is Mondotronics: http://www.mondo.com/shapememoryalloys.shtml

    Interesting stuff, but it does have some limitations/drawbacks.


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    ·1+1=10
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-12-23 15:57
    Limitations - IT is a bit slow to respond.
    Drawbacks - IT uses quite a bit of current to power it.

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    "When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • John R.John R. Posts: 1,376
    edited 2005-12-23 16:08
    Thanks guys, that's the "stuff".

    Another lmitation: It is not as "variable" as I thought, and this also would correspond with the application I saw it in. No current, rock left, apply current, rock right. There was no "proportional" control.

    This may work for some of the stuff I'm after. Speed won't be a problem, and I'm not looking at battery powered devices. This is for some animation on my model railroad.

    For others watching, they (http://www.mondo.com/shapememoryalloys.shtml) have a book and a range of starter kits. Variations of the stuff can also be "pre shapped" and then stretched (within limits) and brought back to original shape by heating (which may be done by passing electric current throught the shape).

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    John R.

    8 + 8 = 10
  • Paul BakerPaul Baker Posts: 6,351
    edited 2005-12-23 16:26
    Muscle wire is suprising like a muscle fiber in behavior, in that its an all or nothing thing, but just like many muscle fibers are combined to provide a full range of motion, some people are trying to create composite muscle wire structures to achieve similar results, Ive seen parallel bundles to provide additional actuation force, and they are trying to implement serial stacking to provide a range of contraction, but this is proving to be much more difficult.

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    ·1+1=10
  • YojimboYojimbo Posts: 40
    edited 2005-12-23 20:07
    I've heard about some rubber that contracts when a current goes through it, anyone have any info on this stuff? I heard about it being used with a toy fish tank where the fish were made out of this stuff and when current was applied, the fish would swim with no moving parts.
  • SN96SN96 Posts: 318
    edited 2005-12-23 20:56
    Muscle wires are perfect for bot hands that do not need to grip anything firmly. Like a small 5 finger hand for example, the wires are routable and not bulky unlike servos or electic motors. I was thinking of making a hand one day and it will use muscle wires.

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    Mike

    ·
  • pharseidpharseid Posts: 192
    edited 2005-12-23 23:05
    · I think the swimming fish was made with electrostrictive actuators. These are essentially capacitors with flexible dielectrics (and electrodes for that matter). The operating voltages for these devices is generally in the thousands of volts. The only manufacturer I know for these is Artificial Muscle Inc. and I don't think they've gone into full production yet. Well, now that I think of it, there are also electrostictive actuators made with crystaline dielectrics, but the % of contraction for these would be very small.

    -phar
  • kelvin jameskelvin james Posts: 531
    edited 2005-12-24 05:06
    www.imagesco.com/catalog/nitinol/index.html
    Air valves look interesting.

    kelvin
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