I need to detect motion on a nylon (transparent) stringed instrument.
When the string is plucked, it would vibrate and I'd like to know what kind of sensor to use in order to detect the action.
Maybe a reflective optical sensor (visual detection) like the ones here? http://www.vishay.com/optical-sensors/reflective-outputisnot-16/
Or a tiny piezo element (detection by sound)? https://www.sparkfun.com/products/9199
I don't think piezo will work because there are more than one string to detect. The strings are close to each other, I guess the sounds will interfere with each other. Maybe using a treshold and computing/choosing the loudest emitter would be a solution. But I would prefer the cleanest way to achieve this.
At best, I do not want to paint the string thinking that it will damage the sustain and / or the color of the sound.