Opodiphthera Incognita

by Matti Niinimäki & Emmi Pouta

[We are still hoping to get some better images or video from somewhere]

The Concept

Opodiphthera Incognita is a dress that changes its color and shape when the user feels threatened. It is not meant to be an actual method of self-defense, but more of a conceptual garment that plays with the idea of shape shifting and primal reactions.

Using Flexinol Wire

Flexinol wire – or muscle wire – is wire that contracts or goes back to a certain shape when it is heated. This effect can be used to create controllable linear motion by heating the wire with electricity. The muscle wire we used was Flexinol 0.010″ diameter high temperature wire from Robotshop. It needs to be heated to 90 °C to activate it.

The wire required about 1 A of current to contract. This meant that we had to use approximately 60 cm long pieces of the wire with our 11.1 V Li-Po battery.

We had a lot of problems trying to figure out the best way to attach the flexinol wire to actually get decent movement with textiles. Paper was much easier since it holds its shape better and can be guided to move in certain way by folding it.

In the end, a zig-zag pattern with tight stitches in the ends and loose stitches in between seemed to be the best way to do it. Although, we weren’t totally happy with that either and only managed to get two small moving pieces for the final dress.

Using Thermochomic Pigments

Usually, thermochromic inks are painted or printed straight to the textile surface, but we wanted to try something different. We painted some red silk yarn with the thermochromic pigment and then used the yarn to weave our own textiles. Black thermochromic pigment was mixed with some silk screen paste to create the ink. The black pigment did not actually come out as black when mixed with the red color of the yarn, but more of a darker red or purple. This turned out to be a nice accident since the dark red was quite beautiful.

We experimented with different kinds of weaving patterns.

We also wove some resistance wire into the fabric that was used as the heating element to change the color. We used resistance wire since we did not have the proper conductive thread with small enough resistance rating.

In the final dress, we had three color-changing strips of fabric with four loops of resistance wire embedded in them. Each length of resistance wire drew roughly 600 mA so in total the color-changing part of the dress drew about 2.4 amps. The total current consumption of the entire dress peaked at about 3.5 amps, so we weren’t really comfortable having anyone actually wearing the dress just in case something had gone wrong.

Muu Gallery Presentation

We had some bad luck when transporting the dress to Muu Gallery and the connections to the resistance wires broke. It seemed to be impossible to solder the resistance wire and the connections were made with some crimp beads. That seemed to work at first, but they actually broke when we took the dress of the mannequin. We were able to fix some of the connections, but in the end, parts of the dress did not change color at the Muu Gallery.

We also did not have time to finish the hood so that it could be moved and used to trigger the movement and color change. We had it set on a timed loop instead.

In the end, we did not quite reach our ambitious goal, but the dress itself looked very beautiful and still changed color and moved slightly. The materials we picked were very challenging to use, but we learned a lot while trying to figure them out.

Defensive Dress Progress

A little update on what we have been doing.

The first test of thermochromic textiles. We tried to test different materials as the heating element. These small patches were woven by hand with various metallic threads and silk thread dyed with the thermochromic ink.

Here is the actual thread we are going to use:

The picture below shows us measuring the length and type of resistance wire we can use. We had two types of wire: 0.3 mm and 0.4 mm. It seems that we need about 300 mA of current to heat the wire to a point where it reacts with the threads dyed with thermochromic ink.

The lengths of wire we can use with a 9V battery:

  • ~ 4 meters of the 0.3 mm wire
  • ~ 5 meters of the 0.4 mm wire

A 9V battery is not really the ideal option since it would drain out really fast when we use 300 mA., but we also need the higher voltage. I think we need to use a bigger LiPo or NiMH battery (7.4V or 11.1V).

Emmi working on the shape of the dress.
Materials:

Puolustuspuku – Defensive Dress

We (Emmi, Matti & Markus) are planning on creating a dress that changes shape and color when the wearer feels threatened. Normally, the dress would appear as any other black dress, but by squeezing the sleeves the dress goes into a defensive mode, where a protective/threatening fin-like collar rises up that also changes its color from black to red.

 

Inspiration

We were inspired by animals that change shape or color to intimidate predators, such as the frill-necked lizard:

And this octopus:

Technology

The movement of the dress is going to be done with shape memory wire (flexinol/nitinol/muscle wire). It is a material that “remembers” its original shape. The wire returns to this shape (or contracts) when heated.

We still have to do a lot of testing with this once we get the wire. We are not quite sure how much movement we can actually achieve with this technology.

A small example from xslabs:

The change in color is achieved with thermochromic inks that change color when heated. We are planning on weaving a material that combines threads dyed with thermochromic pigments and resistance wire for heating it.

A video of our initial testing with threads dyed with thermochromic ink.:

Materials/Shopping List (not final):