Nitinol – Wearable tech – Jovana Ivanovic

SKORPIONS is a set of unique electronic garments which use the shape-memory alloy (SMA) Nitinol. By integrating Nitinol into textiles, it is possible to achieve shape changing, responsive fabrics create to move and change on the body in slow, organic motions. Unfortunately, the process is quite complicated and expensive, therefore there is a large lack of Nitinol-based shape changing garments.

These unique garments utilize electronic fabrics, soft electronic circuits, specially designed circuit boards, magnets, and Nitinol. As for the actual dress, the cut of the pattern and other construction details become an important component of the design. The SKORPIONS’ programming does not respond to sensor data, rather they are more like living organisms or moving sculptures that display characteristics such as control, anticipation, and unpredictability.

 

Nitinol, also known as muscle wire, is composed of nickel and titanium and has the ability to remember and adapt its geometry. In the recent years, application of Nitinol has increased steadily, especially in medicine, such as dental braces that exert a constant pressure on the teeth. However, they are not yet appropriate for robotics or articifical limbs due to energy inefficiency and slow response times.

During its relaxed state, Nitinol can be integrated into a soft fabric without disrupting its natural movement and flexibility due to it being extremely malleable and resistant. Once heated to its shape memory (or austenite) state, a Nitinol wire becomes stiff and it becomes impossible to shape the Nitinol after integration into the fabric. In order to control the specific shape-change, the Nitinol must be constrained into the desired shape, heated to 500ƒC and quenched in water, much like blacksmithing. The kinetic mechanisms utilized in the SKORPIONS utilize several custom shaped Nitinol wires and their integration with textile techniques like knitting, sewing, and hand stitching. Nitinol wire that has been previous shape-set can still be woven into a textile in its martensite state.

ELECTRONICS

To successfully merge textiles with electronics, a new method for making circuits was required. This process involved the use of conductive yarns, inks, and fabrics to allow the construction of soft electronic circuits. Sewing, weaving, embroidery, and knitting was used to combine the two. The use of snaps allows a durable and seamless connection between the flexible threads and the rigid PCB (printed circuit board). The snaps are soldered to the PCB, while at the same time sewn into the dress and connected to the conductive thread. The electronics are kept inside a small inside pocket , and this also allows for the board to be completely removed when necessary.

 

Nitinol is not only used to keep the desired shape change, but it can also, through resistive heating, produce the heat necessary for actuation. Two small rechargeable lithium polymer cells can power the dresses for a couple of hours and allows for interesting movements and actions.

Examples:

 

luttergill6
skwrath4
slofa5

 

enleon6
glutus2

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