Arduino theremin like musical instrument

When I got my Arduino protoshield from sparkfun, I wanted to make something cool with it. And since I had seen a few Theremin projects before, and already thought about making some, I finally made one, using the Parallax PING sonar sensor. Here are some informations about how I made it. You can see all the pictures here

First, the schematics:

Here’s the commented code for the Arduino:

int pingPin = 7;
int buzzPin = 10;
int btnPin = 1;
int val;

void setup()
{
  pinMode(buzzPin, OUTPUT);  //set speaker pin to output
  pinMode(btnPin, INPUT);    //set pushbutton pin to input
}

int getPing()
{
  //send a 10us pulse to wake up the sonar
  pinMode(pingPin, OUTPUT);
  digitalWrite(pingPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(pingPin, LOW);

  //get the raw value from the sonar, corresponding to the
  //actual time of travel of the ultrasound waves
  pinMode(pingPin, INPUT);
  return pulseIn(pingPin, HIGH);  //return this value
}

void loop()
{
  if (digitalRead(btnPin) == HIGH)  //only play when the button is pressed
  {
    val = getPing() / 5;  //you can tune the pitch by dividing by a different number

    //generate the pulse
    digitalWrite(buzzPin, HIGH);
    delayMicroseconds(val);
    digitalWrite(buzzPin, LOW);
    delayMicroseconds(val);
  }
}

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