#define piezoPin A5 // select the input pin -- analog 5
int ledPin = 13; // select the pin for the speaker
int val = 0; //store value from piezo
void setup() {
pinMode(ledPin, OUTPUT); // declare the ledPin as an OUTPUT
Serial.begin(9600);
}
void loop() {
val = analogRead(piezoPin); //read value from piezo
if (val > 500) //you need to find the value for this
{
digitalWrite(ledPin, HIGH);
delay(100); //about how long the LED will stay on.
}
else
{
digitalWrite(ledPin, LOW); //turn off if value isn't high enough
}
Serial.println(val); //debug
}
how to wire the piezo to the arduino

basic, but should work

i know what you mean by example. needed the same thing when i was more of a newb.