After researching potential ways I could create an output from an sensory input, I decided to try to use an Arduino Magpie Microprocessor bought from Little Bird Electronics for the coding for my wearable.
As I have never done any electronics before, I started with some basic projects from the Freetronics Project Guide, and then followed some tutorials on how to program an arduino.
Nitinol During my internet research, I came across these experiments using Nitinol, a shape changing metal alloy that contracts when heat/current is applied to it. What interests me about this material is the architectural implications for a structure that may open/close or respond to the presence of a person. The following links are experiments other people have done using nitinol
Contraction and relaxation depend solely on the temperature of the nitinol alloy wire. Any method of heating and cooling the wire may be used. Nitinol wire has a high electrical resistance, approximately 1.25 ohms resistance per inch for the 6-mil wire. The resistance of the wire to the electric current quickly generates sufficient heat (ohmic heating) to bring the wire through its transition temperature. So many times an electric current is passed through nitinol wire to heat the wire electrically. When the material is allowed to cool, the wire can easily be stretched back it its original length.
Nitinol wire usually has a counter-force applied to it in the opposite direction of its contraction. The counter force resets, or stretches the wire back to its original length when in the low temperature phase. This is called the bias force. If the nitinol wire is brought to its transition temperature without a bias force it will contract, however, when it cools it will not return to its original length
Although it is possible to buy Flexinol pre-crimped, in most cases the hobbyist or student must crimp the wires themselves. The hair-thin nature of most Flexinol gauges makes crimping difficult, but it is certainly possible to get a good crimp with hand tools. There are many potential approaches. In the original Stiquito plans, Mills ties a small, loose knot in the wire and crimps with a section of 1/16 inch aluminum tubing. Roger Gilbertson, author of the Muscle Wires Project Book, recommends the N-scale rail joiners which are used to connect model railroad conductive track. Many builders will use standard solderless terminals from other electronics applications. A good and simple solution for a temporary crimp that can be repositioned is to use standard machine screws and hex nuts.
Flexinol in most applications uses electricity to generate the internal heat needed for transition. Proper control of the current is essential for satisfactory results. Too little current and the wire will fail to contract. Too much current and the wire will overheat, becoming stressed and losing its shape memory properties. In between too little and too much, variations in supplied current will affect the heating and cooling times. In the table reproduced below, Dynalloy provides some guidelines as to how much current is required to cause a Flexinol wire of a given gauge to contract in one second. Also provided is the approximate electrical resistance of the various gauges. Note that Flexinol has fairly high resistance compared with copper wire and other common conductors. In some applications it is possible to activate the wire without additional resistance in the circuit. A 0.005" diameter wire has a resistance of about 1.9 ohms per inch and needs about 320mA to reach its transition temperature - to heat a 5-inch length of 0.005" Flexinol will require about 3 volts which could come directly from two standard AA batteries. (Volts = Resistance in ohms * Current in amps.) Of course Flexinol is hungry for current and it would be easy to overload a wire. If above there were 2 inches of wire rather than 5, that same 3 volts would deliver 1.58 amps and likely destroy the Flexinol.
Wearable Creating a wearable electronic piece presents problems as the piece has to be first and foremost safe (not going to catch fire or electrocute the wearer), and presents further problems with how the electronics, battery components etc will be integrated into the clothing. Some links that look at wearable pieces are:
I started to think about my concept, and what my input and output could be for the project.
What interested me about my site is the juxtaposition between distance and proximity, and how one might sense distance - whether it is though sound, touch, smell, taste or seeing. The reason distance and proximity struck me as a potential input about my chosen site is that one of the elements on my site is the Ingham Multiplication farm. This consists of 56 sheds on a very wide plot composed of grass and rolling hills. The site feels very remote, but if one were to go inside the sheds, they would find a very closely packed space. The difference between the activity within the sheds and the amount of area each chicken is allocated, and the comparatively vast area of the plot, is something I could potentially investigate through my analogue.
Another more literal input could be the wind over the rolling hills. This strikes me as I think you could create something quite beautiful and poetic, and having something that responds to the wind by creating a sound or a light. Two such projects I have found online that has investigated the wind as an input, or sound or light as an output are:
Dandelion a wearable portable piece with spinning blades that generate electricity to power an LED in the center of each windmill.
The Story of the Wind, a project from the Copenhagen Institute of Interactive Design where,
"The dress has two main inputs. First, there is input from the movement when the user shapes the dress to capture the wind. The other input is the strength of the wind as it is captured by the fabric. As the user experiences the gentleness or forcefulness of the wind, they are also able to hear the wind in different way. We were able to achieve this system by using a Lilypad Arduino and conductive thread to connect sensors. With the intensity of the wind, data is collected by a piezo sensor that is then translated into sound. Depending on the shape that the user creates to capture the wind, data from tilt sensors also change the expression of this sound."
Wingsz is another project that while doesn't involve an input/output, the forms created by the wind and the relationship to the body are very poetic.
Another beautiful object that doesn't necessarily have an input/output are these kinetic wing jewelry by Dukno Yoon, where the movement of a persons fingers make the wings "fly".
A proximity responsive LED table by Graham Monahan Some initial brainstorming:
Privacy
All from this page, from a blog from the Carnegie Mellon School of Art for the course Electronic Media Studio 2. I like the devices above because a lot of them are quite playful and humorous, especially the voice activated blender.
