[Yaaarc] Conductive fabric, electronic clothing

[Paul Haas]

One of the things we discussed at the meeting was wearable electronics.

SparkFun electronics sells some electronics designed to be sewn into
clothing and other fabric projects.
http://www.sparkfun.com/commerce/categories.php?cPath=2_135

They were designed by Leah Buechley
http://www.cs.colorado.edu/~buechley/projects/e-textile_kit/e-textile_kit2.html

The conductive fabric is available from a site that seems to cater to
the tinfoil hat crowd: http://www.lessemf.com/fabric.html

Leah's site shows how to make switches entirely out of fabric
http://www.cs.colorado.edu/~buechley/diy/diy_e_sewing.html#switch

The resistance of the stretchy fabric varies with how much it is
stretched, so you can measure how much a joint is bent by making a
voltage divider out of the fabric, such that half of it stretches with
the joint. The nonstretched half will compensate for temperature and
increased resistance from washing. This can be fed directly into an
A2D port on an Arduino board. If you didn't follow the above links, a
couple of them point to Arduino boards designed to be sewn into
fabric.

The easiest things to make with conductive fabric are heaters.

The fabric is rated in Ohms per square.  Resistance per square is also
used to rate stuff like copper cladding on circuit boards.  If you
measure the resistance of a rectangle, the resistance will go up as
you make the rectangle longer. The resistance will go down as you make
the rectangle wider. If your rectangle is a square, those two effects
cancel out, so the resistance is independent of the size of the
square.

There are also some instructables about conductive fabrics and glues.
http://www.instructables.com/id/Conductive-Fabric-Make-Flexible-Circuits-Using-An/

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Paul Haas