See: http://en.wikipedia.org/wiki/Memory_wire

The nickle-titanium alloy probably has the best properties. One use is for frames for glasses that don't easily take a set. Another is in small actuator for model airplanes. John

 

yeah, i had read through that first,
but i couldn't see how it might apply,
so i thought there must be something else about it ...

But now i think that it won't do quite what you think it does.
Unless ive got it wrong. Which wouldn't be the first time.

It seems that if it gets distorted,
its supposed to return to its intended shape by heating it up a bit.

I don't think it can be made to bend and un-bend,
by repeatedly heating and cooling.

However,
the notion of using heat is a good one,
a length of wire could be used in that way, to move mechanical pixels.
That need not be very expensive per pixel.

It probably wouldn't be very fast either.
But good enough for an interesting display.

John

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It is not as fast as a servo in the applications I have read about, but it is sufficiently fast for control of indoor model airplanes. The advantage I see is that you could use a grid and get heat at the X-Y intersections. It would seem to be a lot easier to build a 25X25 grid than connect up 625 servos. John

 

I'm curious what sort of mechanical device would move something at a X-Y intersection of muscle wire. It's also far too slow for a matrix with real time updates like the wooden mirror.

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

Hi,

JPANHALT:
I've been reading up a bit on these "memory wires",
and you are correct, they can be made to 'bend and un-bend" repeatedly
by heating and cooling.
And yes, they are used as actuators in some model aircraft.
So they could possibly be used in a similar way to operate a wooden
pixel as part of an array.

BLUEROOMELECTRONICS:
Yes, it would be a bit slow but if the movement required was short then
it could be fast enough to produce interesting results.

As to the intersection ...

I don't think that jpanhalt meant that the X and Y wiring would be "muscle wire",
that would be ordinary wire, the "muscle wire" would be fed from the intersections.

The wooden 'pixels' would just be pivoted on pins, and they would take very little
effort to change angle, the actuator could be positioned so that a small
movement caused a significant change of angle of the 'pixel'.

A lot of trouble to make an array of even 100 X 100, but i would think possible.

Regards, John

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That is essentially correct. I was thinking that heat transfer from a hot node would allow more flexibility in design; however, I would not rule out the muscle wire as being at least one and many both of the conductors.

One would need to know more about the physical design to go further on the muscle wire design. Flipping parallel to the X or Y axes would yield something similar to the original work d'art and the project as described by the OP.

Perhaps, just to be contrary, one could rotate on the perpendicular (Z) axis. That could lead to a different mechanical arrangement, and I think it might even present a more interesting effect to the observer.

John

John