/* Program 2-6 send 440 Hz signal to the buzzer 
 *
 * This program uses Arduino function tone() to drive pin 8 at 440 Hz. 
 * Pin 6 is connected to the speaker buzzer.
 */
const int BUZZER = 6;

void setup() {                
}
void loop() {
    /* send 440 Hz signal to buzzer for a second */
    tone(BUZZER, 440);
    delay(1000);
    /* turn off output to buzzer for a second */
    noTone(BUZZER);
    delay(1000);
}