Nitinol

I've been having a lot of trouble attempting to get Nitinol wire working in my electronic textiles. I was wondering if anyone had any advice? This is really the only forum I could think of asking this on.
I have it controlled by a Lilypad Arduino, but I had to create another circuit to control high current loads (the arduino can't handle them) with a transistor, that grabs the power directly from the power source rather than the Arduino. I'm taking the power from the usb drive of my computer. The problem is, this still isn't enough power, all I can make move is about 2 inches of nitnol and this really isn't enough. I don't even know what I could use as a power source other than the USB, I don't think any of the batteries I'm using have enough current to cause the Nitinol to contract.
I'm not sure what I'm missing here, I don't have much background in electronics, just what I've taugh myself over the last few years while learning how to incorperate them into my textiles.
Any ideas? Any help would be really really appreciated.

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Permalink Reply by chris on March 2, 2009 at 1:02pm

Hi, you really need a lot of power to heat up the nitinol wire so that it will change. the power you need depends on many reasons (e.g wire diameter, electrical resistance,lenght ...) so i cant tell how much you need exactly. try a battery with a high current load, for example nimh-types with about 1A or lithium batt...

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Permalink Reply by Marisa on March 22, 2009 at 8:28am

I finally got a hold of a battery with a high enough current, that was definitely the problem. Thank you!

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Permalink Reply by Hillevi on March 24, 2009 at 8:37am

Hi,

How do you connect the wire to the battery? It looks to me that the wire itself doesn't have enough resistance to heat, which obviously can't be right. I've been using a 3 - 12V adapter.