[Arduino Uno R3] The doremi sound by buzer.

You can control the buzer sound tone using delay and digitalWrite.
The buzer tone is controlled by vibration period.
Following is vibration period for doremi.
C - 262
D - 294
E - 330
F - 349
G - 392
A - 440
B - 494
High C - 523
...

Demo

Code

#define DX 12

int abc[] = {262, 294, 330, 370, 392, 440, 494, 523};

// the setup routine runs once when you press reset:

void setup() {

  // initialize the digital pin as an output.

  pinMode(DX, OUTPUT);

}

// the loop routine runs over and over again forever:

void loop() {

  for(int i = 0; i < 8; i++)

  {

    mtone(DX, abc[i], 500); // abc[i] tone sound for 0.5 second

    delay(50);

  }

}

void mtone(int dx, int hz, unsigned long tm)

{

  unsigned long t = millis();

  unsigned long ns = (long)500000 / hz;

  

  // Repeats for tm milliseconds.

  // Sounds for tm milliseconds

  while(millis() - t < tm)

  {

    digitalWrite(dx, HIGH);

    delayMicroseconds(ns);

    digitalWrite(dx, LOW);

    delayMicroseconds(ns);

  }

}

Description

millics() : The function to get past time by milliseconds since starting Arduino.
tone() : It's a function provide by Arduion which is the same as mtone. So you can change the code mtone -> tone.