If the circuit is closed, it says: 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
If the circuit isn't closed, it says: 0,0,0,1,1,0,1,0,0,0,1,1,1,1,0,0,1,1,1,0,0,0,1
What circuit? Quit waving your arms and post a schematic, a picture, or, at a minimum, a description of what is connected where. Post your code.
What you describe sounds like a floating pin condition, caused be lack of pullup or pulldown resistors.
Sorry, but how can I do this?
Using digitalRead().
Can you give me an example, please?
I don't know what your circuit looks like. I'm assuming that your piece of plastic is holding a switch open, and that removing the plastic allows the switch to close.
If that is correct, then one end of the switch goes to a digital pin, and the other end goes to ground.
Then, in setup:
pinMode(somePin, INPUT);
digitalWrite(somePin, HIGH); // Turn on the pullup resistor
Then, in loop:
int state = digitalRead(somePin);
if(state == LOW)
{
// The plastic piece is gone. Raise a squawk.
}