Make Some Noise

BRIEF Sound is just fast wiggling

Every sound you have ever heard is air wiggling. Wiggle it 440 times a second and you hear the note A. Wiggle it faster, the note rises. Your kit has two little speakers called buzzers, and your board can wiggle them at any speed you ask. Which means today you build a siren, then program an actual melody, note by note, and finish with a machine that plays it on demand.

Time: 45–60 minutes · Difficulty: 2/5 · You need: Lesson 03 done (buttons).

KIT What you need

• R3 board with USB cable
• Breadboard
• Both buzzers, they look like twins but are not (see below)
• 1 push button
• Jumper wires

BUILD Wire it

Unplug the USB. Start with the passive buzzer (the open-back one), it is today's star. Buzzers have a + marking on top; the + leg is often longer too.

From	To	Why
R3 pin 8	Passive buzzer + leg	The wiggle wire
Passive buzzer − leg	R3 GND	Loop complete
R3 pin 4	Button leg · other leg to GND	The play button, like Lesson 03

CODE Program it, siren first

// GAMERIFT Beginner Kit, Lesson 08: Make Some Noise
// Part 1: the classic rising-falling siren.

const int buzzerPin = 8;

void setup() { }

void loop() {
  for (int f = 400; f < 1200; f = f + 10) {  // pitch climbs...
    tone(buzzerPin, f);
    delay(5);
  }
  for (int f = 1200; f > 400; f = f - 10) {  // ...and falls
    tone(buzzerPin, f);
    delay(5);
  }
}

Upload. Siren. Enjoy it for exactly as long as your family allows. Now the real music, replace everything with:

// Part 2: a melody, note by note, on the button.

const int buzzerPin = 8;
const int buttonPin = 4;

// Frequencies for one octave (C D E F G A B C)
const int notes[8] = {262, 294, 330, 349, 392, 440, 494, 523};

// A tune as positions in the scale: change these and you change the song!
const int tune[]      = {0, 0, 4, 4, 5, 5, 4};
const int beats[]     = {1, 1, 1, 1, 1, 1, 2};
const int tuneLength  = 7;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
  if (digitalRead(buttonPin) == LOW) {          // pressed: play!
    for (int i = 0; i < tuneLength; i++) {
      tone(buzzerPin, notes[tune[i]]);           // look up the note
      delay(300 * beats[i]);                     // hold it for its beats
      noTone(buzzerPin);                          // tiny gap between notes
      delay(40);
    }
  }
}

1. Upload and press the button. Recognise it? (It is the opening of "Twinkle Twinkle", which is also, sneakily, the alphabet song.)
2. Change the numbers in tune[] and press again. You are composing.

BREAK IT Now break it on purpose

1. Swap in the active buzzer and run the siren. Instead of a smooth wail you get a strangled stutter, the built-in musician fights your wiggling. Right part, wrong job. Swap back.
2. tone(buzzerPin, 40), then tone(buzzerPin, 15000). One is almost too low to hear, one almost too high (ask the nearest adult if they can hear 15000, they probably cannot, your ears lose the top notes with age).
3. Delete the noTone() line. The notes now smear into each other like a robot slurring. Those 40 milliseconds of silence were doing more work than you thought.

REMIX Make it yours

• Compose: program a tune you actually like, 10 to 15 notes. Hint: hum it slowly and work out whether each note steps up, steps down or repeats.
• Alarm clock voice: three urgent beeps, pause, repeat, the universal "get up" sound. You will use this in Lesson 11.
• The unignorable doorbell: button plays your melody, but each press picks a random note order. Chaos doorbell.

LOG IT Show and tell

Record your composition for your lesson log (sound on, obviously). Stuck? Contact us with a photo and we will listen for the problem.