Drop Light - IO Coincidence

Drop the ball to turn the light on and off.
https://www.youtube.com/watch?v=9DUadJ-OBf0
A drop is detected by an analogRead on the piezo speaker. After some experimentation I came to a fairly low threshold (10) to recognize soft drops.  I think I could have weighted the ball more to increase reliability and get more sizable readings.
 
I didn't do much coding of my own on this one.  Mostly re-using the knock sensor example to gather input from the piezo speaker.
 
/* Knock Sensor

 * ----------------

 *

 * Program using a Piezo element as if it was a knock sensor.

 *

 * We have to basically listen to an analog pin and detect

 * if the signal goes over a certain threshold. It writes

 * "knock" to the serial port if the Threshold is crossed,

 * and toggles the LED on pin 13.

 *

 * (cleft) 2005 D. Cuartielles for K3

 * edited by Scott Fitzgerald 14 April 2013

 */

 
int ledPin = 11;

int knockSensor = 5;               

byte val = 0;

int statePin = LOW;

int THRESHOLD = 10;

void setup() {

 pinMode(ledPin, OUTPUT);

 Serial.begin(9600);

}

void loop() {

  val = analogRead(knockSensor);
  Serial.println(val);  

  if (val >= THRESHOLD) {

    statePin = !statePin;

    digitalWrite(ledPin, statePin);

    Serial.println("Knock!");

  }

  delay(300);  // we have to make a delay to avoid overloading the serial port

}