The swatches I made this year use conductive yarns to create pressure sensors around threadbare garments. The sensors can be connected to an Arduino or Pure Data circuit (see below, add pull-up/down resistors from the input if needed), and the feedback used to create musical or dance scores that are based on the worn areas.
I’ve been using the “Light_Tempreture_Multi_Oscil” sketch from the Mozzi synth library for Arduino. Download the library and examples here: http://sensorium.github.io/Mozzi/
I’ve also used the sensor for MIDI input using Pure Data, I adapted an Arduino patch using this tutorial: https://spencerdixon.wordpress.com/2010/12/15/how-to-build-a-midi-controller-with-the-arduino-firmata-and-pure-data/