What is the best way to get 0 or 1 input from 9 piezos? That isn't multiple, only 1 at a time. But the problem is I have to use only the analog pins (6 here in arduino uno). I am doing that in some ways, but any good ways to that with some safety wiring ?
What's triggering/activating the piezos?
I am doing that in some ways
What would that be? Can we see a schematic?
but any good ways to that with some safety wiring?
What do you mean by safe? A piezo usually won't hurt you or the Arduino.
A piezo isn't digital... It's an impulse or AC... It cannot hold a logic-1 or logic-0 state and the voltage depends on the amount of impact/vibration.
OK... If you're getting 5V out of it that's a (momentary) logic high... Like I said, it won't hold logic-high, but if you're 'polling' the input in a fast-loop you can read it, or if you set-up an interrupt you an detect the state-change.