In previous lessons, we learned how to control a buzzer to produce different sounds. Now, can we combine these notes by adjusting their frequency and duration to create a complete melody? In this project, we will use a buzzer to play music and learn how to create header files (.h files) to import pre-written note table.
When programming with the Arduino IDE, each project file is called a "Sketch". A Sketch can contain multiple code files. To avoid having an overly long and unreadable program, you can write the main logic of the program in the main file and store independent functional modules in other files for easier management and maintenance. This approach not only improves the readability of the code but also facilitates the reuse and expansion of functionalities.
COMPONENT LIST
HARDWARE
Connect it according to the following wiring diagram, pay attention to the positive (+) and negative (-) pins of the buzzer. The pin marked with + is connected to digital port 8, and the other one is connected to GND. The positive and negative of the buzzer can be checked through the + symbol on the cover.
fig 1 Melody Buzzer Circuit
CODE
Sample code - Main Sketch():
//Project - Melody Buzzer
#include "pitches.h" //include a header file
int melody[] = {
NOTE_C4, NOTE_G3, NOTE_G3, NOTE_A3, NOTE_G3, 0, NOTE_B3, NOTE_C4
}; //sequence of notes in the melody
int noteTypes[] = {
4, 8, 8, 4, 4, 4, 4, 4
}; //type of each note: 4 = quarter note, 8 = eighth note
void setup() {
for (int thisNote = 0; thisNote < 8; thisNote++) {
int noteDuration = 1000 / noteTypes[thisNote];
//calculate the note duration: 1 second / note type
tone(8, melody[thisNote], noteDuration);
//play the note on pin 8
int pauseBetweenNotes = noteDuration * 1.30; /*calculate the pause time according to the note duration to make the melody sound more natural*/
delay(pauseBetweenNotes); //pause between the notes
noTone(8); //stop the tone playing on pin 8
}
}
void loop() {
// no need to repeat the melody
}Create a new header file. Click the button below the Serial Monitor, select 'New Tab', enter the filename pitches.h.
pitches.h：pitches.h：pitches.h：pitches.h：pitches.h：itches.h：
#define NOTE_B0 31
#define NOTE_C1 33
#define NOTE_CS1 35
#define NOTE_D1 37
#define NOTE_DS1 39
#define NOTE_E1 41
#define NOTE_F1 44
#define NOTE_FS1 46
#define NOTE_G1 49
#define NOTE_GS1 52
#define NOTE_A1 55
#define NOTE_AS1 58
#define NOTE_B1 62
#define NOTE_C2 65
#define NOTE_CS2 69
#define NOTE_D2 73
#define NOTE_DS2 78
#define NOTE_E2 82
#define NOTE_F2 87
#define NOTE_FS2 93
#define NOTE_G2 98
#define NOTE_GS2 104
#define NOTE_A2 110
#define NOTE_AS2 117
#define NOTE_B2 123
#define NOTE_C3 131
#define NOTE_CS3 139
#define NOTE_D3 147
#define NOTE_DS3 156
#define NOTE_E3 165
#define NOTE_F3 175
#define NOTE_FS3 185
#define NOTE_G3 196
#define NOTE_GS3 208
#define NOTE_A3 220
#define NOTE_AS3 233
#define NOTE_B3 247
#define NOTE_C4 262
#define NOTE_CS4 277
#define NOTE_D4 294
#define NOTE_DS4 311
#define NOTE_E4 330
#define NOTE_F4 349
#define NOTE_FS4 370
#define NOTE_G4 392
#define NOTE_GS4 415
#define NOTE_A4 440
#define NOTE_AS4 466
#define NOTE_B4 494
#define NOTE_C5 523
#define NOTE_CS5 554
#define NOTE_D5 587
#define NOTE_DS5 622
#define NOTE_E5 659
#define NOTE_F5 698
#define NOTE_FS5 740
#define NOTE_G5 784
#define NOTE_GS5 831
#define NOTE_A5 880
#define NOTE_AS5 932
#define NOTE_B5 988
#define NOTE_C6 1047
#define NOTE_CS6 1109
#define NOTE_D6 1175
#define NOTE_DS6 1245
#define NOTE_E6 1319
#define NOTE_F6 1397
#define NOTE_FS6 1480
#define NOTE_G6 1568
#define NOTE_GS6 1661
#define NOTE_A6 1760
#define NOTE_AS6 1865
#define NOTE_B6 1976
#define NOTE_C7 2093
#define NOTE_CS7 2217
#define NOTE_D7 2349
#define NOTE_DS7 2489
#define NOTE_E7 2637
#define NOTE_F7 2794
#define NOTE_FS7 2960
#define NOTE_G7 3136
#define NOTE_GS7 3322
#define NOTE_A7 3520
#define NOTE_AS7 3729
#define NOTE_B7 3951
#define NOTE_C8 4186
#define NOTE_CS8 4435
#define NOTE_D8 4699
#define NOTE_DS8 4978CODE REVIEW
In this project, we created a new header file and copied a piece of code into it. From Project[Temperature Alarm], we learned that different frequencies produce different pitches. The code we copied is a note table originally written by Brett Hagman, which includes the frequencies corresponding to all typical notes. For example, NOTE_C4 represents middle C, corresponding to a frequency of 262 Hz. With this note table, we can write melodies by using the names of the notes.
In the program, we first created two arrays to store the melody and note types.
int melody[] = {
NOTE_C4, NOTE_G3, NOTE_G3, NOTE_A3, NOTE_G3, 0, NOTE_B3, NOTE_C4
};
int noteTypes[] = {
4, 8, 8, 4, 4, 4, 4, 4
};
The array noteTypes[] defined above specifies the duration of each note using a simplified representation, where the numbers represent the "type" of the note rather than the exact milliseconds. For instance, 4 stands for a quarter note, and 8 represents an eighth note. The actual duration will be calculated within the setup() function.
An array is a collection of variables, and its elements can be accessed using an index number. As we can see, the array we created has 8 elements. Arrays are indexed starting from 0, so the index numbers of the 8 elements in the array are 0 to 7.
The melody will only play once, so we write the code to play the notes in the setup.
Using a for loop to iterate through each element in the array, the variable thisNote represents the current element's index.
for (int thisNote = 0; thisNote < 8; thisNote++) {
int noteDuration = 1000 / noteTypes[thisNote];
//calculate the note duration: 1 second / note type
tone(8, melody[thisNote], noteDuration);
//play the note on pin 8
int pauseBetweenNotes = noteDuration * 1.30; /*calculate the pause time according to the note duration to make the melody sound more natural*/
delay(pauseBetweenNotes); //pause between the notes
noTone(8); //stop the tone playing on pin 8
}
Calculate the note duration. Since a quarter note is 1/4 of a measure, its duration is the measure time (1 second here) divided by 4.
The tone() function is used to set the pin, frequency, and duration to play the note.
There needs to be an interval between each note to distinguish them clearly, so a delay is needed between the notes. Using noteDuration * 1.30 will give a good effect. You can also try setting a fixed delay of delay(200) to see how the effect differs.
Use noTone to stop the sound.
HARDWARE REVIEW
The Arduino board is typically equipped with a Reset Button, which is highly useful in various aspects, especially during programming, debugging, and restarting the Arduino. The primary function of the Reset Button is to reset the state of the microcontroller (such as the ATmega series) on the Arduino board, analogous to a reboot operation on a computer but specifically targeting the microcontroller itself.
The Reset Button on the Arduino UNO is usually located at the top-left corner of the board, as shown in Fig 2, near the USB port or other I/O interfaces. It is a small button with the word "RESET" marked on it. Additionally, you can also use the Reset Button on the Prototyping Shield to restart the program running inside the Arduino.
fig 2 Arduino's Reset Button
fig 3 Prototyping Shield's Reset Button
EXERCISE
Do you have any familiar melodies that you'd like to play using the buzzer? For example, 'Twinkle, Twinkle, Little Star' or 'Mary Had a Little Lamb'? Try changing the notes and rhythms in the arrays. Don't forget to adjust the number in the for loop!
Melody_Buzzer_English.zip 
