Pre-defined songs for musical organ. More...

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Functions
void	play_twinkle_little_star ()
	Plays "Twinkle Twinkle Little Star" melody.

void	play_imperial_march ()
	Plays "Imperial March" (Darth Vader's Theme) from Star Wars.

Detailed Description

Pre-defined songs for musical organ.

Author: Roybel Carbonell Camejo

Date: 2026-04-29

Version: 1.1

Declares functions to play pre-programmed songs via USART commands. Songs are triggered by numeric keys (e.g., '1' for Twinkle Star, '2' for Imperial March).

Available Songs

Key	Function	Song Title	Duration
'1'	play_twinkle_little_star()	Twinkle Twinkle Little Star	~10-15 sec
'2'	play_imperial_march()	Imperial March (Star Wars)	~30 sec

Usage

#include "pre_defined_songs.h"
 
// In main.c serial command handling
switch(receivedChar) {
    case '1':
        play_twinkle_little_star();
        printString("\r\nPlaying Twinkle Twinkle Little Star\r\n");
        break;
    case '2':
        play_imperial_march();
        printString("\r\nPlaying Imperial March\r\n");
        break;
}

Definition in file pre_defined_songs.h.

Function Documentation

◆ play_imperial_march()

void play_imperial_march ( )

Plays "Imperial March" (Darth Vader's Theme) from Star Wars.

Blocking function that plays the iconic Imperial March theme composed by John Williams for Star Wars: The Empire Strikes Back (1980). Associated with Darth Vader and the Galactic Empire.

Composition Details

Composer: John Williams
Movie: Star Wars: Episode V - The Empire Strikes Back (1980)
Key: E minor (Em)
Time Signature: 4/4 (march tempo)
Original Tempo: ~104 BPM
Duration: ~30 seconds (complete main theme)

Musical Structure

The piece follows this structure:

* Intro (4 bars) | Main Theme A (4 bars) | Main Theme B (4 bars) |
* Bridge (4 bars) | Main Theme A (4 bars) | Build-up (3 bars) |
* Climax (5 bars) | Resolution (4 bars) | Coda (6 bars)
*

Melody (C major scale)

* G3 - G3 - G3 - (G3 D#3) G3 | G3 G3 G3 D#3 G3 |
* C4 C4 C4 G3 C4 | A#3 A#3 A#3 F3 A#3 |
* [Pattern repeats with variations]
*

Trivia & Cultural Impact

One of the most recognizable film themes in cinema history
Often used in popular culture to denote villainy or impending doom
Has been performed by numerous orchestras worldwide
Frequently appears in video games, memes, and parodies

Usage

// Play the Imperial March
play_imperial_march();
 
// Trigger with '2' in main.c
if (receivedChar == '2') {
    play_imperial_march();
    printString("\r\n*** Imperial March ***\r\n");
}

Note: Blocking function - no serial input accepted while playing; Triggered by pressing '2' in the main program (recommended); The theme uses notes from G3 to F4 (range: G3, G#3, A#3, C4, D4, D#4, E4, F4)

Warning

This is a blocking function - the microcontroller will not respond to any serial commands until the song finishes (~30 seconds)

Note durations are affected by global currentNoteLength variable

For authentic tempo, ensure currentNoteLength matches intended duration

Use Q (250ms) for faster, more dramatic tempo
Use H (500ms) for slower, more ominous tempo

Bug:: Current blocking implementation prevents interrupt during playback

Todo:

Implement non-blocking version using timer interrupts

Add ability to stop playback mid-song (emergency stop)

See also: play_twinkle_little_star() Another pre-defined song; playNote() Core function for note playback; scale16.h Contains note definitions (G3, C4, F4, etc.)

Examples: /home/luka/WORK/Programming/ARDUINO/AVR-Square-Wave-Organ/src/main.c, and /home/luka/WORK/Programming/ARDUINO/AVR-Square-Wave-Organ/src/pre_defined_songs.c.

Referenced by main().

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◆ play_twinkle_little_star()

void play_twinkle_little_star ( )

Plays "Twinkle Twinkle Little Star" melody.

Blocking function that plays the classic children's song "Twinkle Twinkle Little Star" through the buzzer.

Melody (C major scale)

* CC GG AA G - FF EE DD C - GG FF EE D - GG FF EE D -
* CC GG AA G - FF EE DD C
*

Song Information

Composer: Traditional/French folk melody (1761)
Lyrics by: Jane Taylor (1806)
Key: C major
Time Signature: 4/4
Tempo: Andante (~120 BPM with Q=250ms)
Duration: ~10-15 seconds (depends on note duration mode)

Note: Blocking function - no serial input accepted while playing; Triggered by pressing '1' in the main program

Warning: Note durations are affected by global currentNoteLength variable; If currentNoteLength = H (500ms), song plays slower If currentNoteLength = Q (250ms), song plays faster

See also: playNote() from organ.h for individual note playback; currentNoteLength in main.c for duration control; play_imperial_march() Another pre-defined song

Implements the complete Twinkle Twinkle Little Star song using fixed note durations (Q=250ms for eighth notes, H=500ms for quarter notes). The song has 42 notes organized in 6 phrases of 7 notes each.

Song Structure (42 notes, 6 phrases)

* Phrase 1: C4  C4  G4  G4  A4  A4  G4  (Twinkle twinkle little star)
* Phrase 2: F4  F4  E4  E4  D4  D4  C4  (How I wonder what you are)
* Phrase 3: G4  G4  F4  F4  E4  E4  D4  (Up above the world so high)
* Phrase 4: G4  G4  F4  F4  E4  E4  D4  (Like a diamond in the sky)
* Phrase 5: C4  C4  G4  G4  A4  A4  G4  (Twinkle twinkle little star)
* Phrase 6: F4  F4  E4  E4  D4  D4  C4  (How I wonder what you are)
*

Rhythm Pattern

First 6 notes of each phrase: Q (250ms) - eighth notes
Last note of each phrase: H (500ms) - quarter note (held longer)
Creates a "swing" feel typical of children's songs

Note Frequency Analysis

Note	Frequency (Hz)	Period (μs)	Timer Value
C4	261.63	3822	1911
D4	293.66	3405	1702
E4	329.63	3033	1516
F4	349.23	2863	1431
G4	392.00	2551	1275
A4	440.00	2272	1136

@complexity O(n) where n = 42 notes @performance Takes ~10-15 seconds to complete (Q=250ms, H=500ms)

Bug:: None known for this implementation

See also: play_imperial_march() Another pre-defined song; playNote() Core function that generates tones

Note: This function is blocking - no other code executes during playback

Warning: Do not modify the arrays while the song is playing (not possible anyway)

Array of notes for Twinkle Twinkle Little Star

Contains 42 note frequency values in sequence. Values correspond to C4, G4, A4, F4, E4, D4 from scale16.h.

Note: Stored in flash memory (const qualifier in global scope)

See also: scale16.h for note definitions (C4, G4, A4, F4, E4, D4)

Array of durations for Twinkle Twinkle Little Star

Each duration corresponds to the note at the same index in estrellita_notas[]. Uses Q (250ms) for short notes and H (500ms) for notes that should be held longer.

Note: Pattern: 6 short notes + 1 long note repeated 6 times

See also: scale16.h for duration definitions (Q=250, H=500)

Play each note in sequence

Iterates through all 42 notes and plays each with its corresponding duration. The loop is blocking.

Invariant: i always ranges from 0 to 41 @ensures All 42 notes have been played

Examples: /home/luka/WORK/Programming/ARDUINO/AVR-Square-Wave-Organ/src/main.c, and /home/luka/WORK/Programming/ARDUINO/AVR-Square-Wave-Organ/src/pre_defined_songs.c.

Definition at line 82 of file pre_defined_songs.c.

References A4, C4, D4, E4, F4, G4, H, playNote(), and Q.

Referenced by main().

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Functions

Detailed Description

Available Songs

Usage

Function Documentation

◆ play_imperial_march()

Composition Details

Musical Structure

Melody (C major scale)

Trivia & Cultural Impact

Usage

◆ play_twinkle_little_star()

Melody (C major scale)

Song Information

Song Structure (42 notes, 6 phrases)

Rhythm Pattern

Note Frequency Analysis