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?

Do you want to know hard hard they are touched or just that they were touched?

What are the strings made from?

How long are they?

What are the stretched between?