Detect a touch to the threads

Hello. I have a lot of threads stretched vertically. I want to detect the touch them. So that you can then play them like a guitar for example).

What is the easiest way to do it (detect touch, not to make a guitar)? What kind of sensors could you recommend for that?

This may give you a few ideas

http://www.instructables.com/id/Touche-for-Arduino-Advanced-touch-sensing/

and here

http://www.arduino.cc/playground/Code/CapacitiveSensor

Are your threads conductive? If they are then it is relatively simple using the high impedance of a cmos logic gate. If not then it is much more difficult. Attaching the threads to springs and measuring the displacement of the string might work. Capacitive sensors will not.