/* By pressing the pushbutton, a sound is generated, which is audible from
  the speaker
   https://github.com/ostad-ai/Arduino-Tutorial
*/
// when the pushbutton is pressed, a square wave is generated by tone() 
// function, which is heard from the speaker connected to a digital pin.
const int button_pin=12, speaker_pin=4;
int const pitch=262; // the frequency 
void setup() {
  // put your setup code here, to run once:
  pinMode(button_pin, INPUT_PULLUP);
  pinMode(speaker_pin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  int state=digitalRead(button_pin);
  if (state==LOW)
    tone(speaker_pin,pitch);
  else
  noTone(speaker_pin);
}