Newsgroups: comp.robotics
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From: sandler@gandalf.ee.udel.edu (Sandman)
Subject: Re: Nitinol Wire Qs?
Message-ID: <1993May19.040933.7971@udel.edu>
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References: <gleepC718pI.Gny@netcom.com>
Date: Wed, 19 May 1993 04:09:33 GMT
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In article <gleepC718pI.Gny@netcom.com> gleep@netcom.com (Steve McIntosh) writes:
>I've been playing around with some Nitinol Wire which a friend
>gave me.. Does anybody know if the contraction is proportional
>to the wires temperature, or is there some kind of snap point?
>
>Has anybody tried to control the amount of contraction by 
>controlling the temperature by using an on/off duty cycle
>on the voltage??
>
>Thanks in advance...

The wire contracts at a certain heat.  If you control the amount of energy 
you put in the  wire it will contract at different rates (You do need to
stretch it back into possition, it wil not shrink then grow.. unless you
have tension on it).

I only experimented with speed in trying to get it to heat fast not slow
and controled (I used relays hooked right to 9V batteries.  The battery
if left on too long (ms) would fry the NiTi wire.  This was faster than
connecting it through a transistor)



