Digital Keyboard with Sound Output using Arduino

Published August 28, 2025 © MIT

Build an Arduino Keyboard that Plays Real Notes

This project creates a simple digital keyboard that uses push buttons to play musical notes through a piezo buzzer with Arduino.

BeginnerFull instructions provided1 hour138

Build an Arduino Keyboard that Plays Real Notes

Things used in this project

Hardware components

Breadboard (generic)

Arduino UNO

USB-A to B Cable

Amazon Web Services Push Button

Resistor 10k ohm

Resistor 1M ohm

Resistor 330 ohm

Buzzer, Piezo

Software apps and online services

Arduino IDE

Fritzing

Hand tools and fabrication machines

Amazon Web Services Arduino Starter Kit

Story

Digital Keyboard with Sound Output using Arduino

1. Detailed Project Description

This project demonstrates the design and implementation of a simple digital keyboard with sound output, using an Arduino microcontroller, a piezo buzzer, and four tactile push buttons. The main objective of the exercise is to build a small musical instrument that generates different tones depending on which button is pressed. This approach allows beginners to understand the concepts of analog signal reading, sound generation, and user interaction with microcontrollers in a very practical and engaging way.

2. How the System Works

The push buttons are connected to the Arduino through resistors, which form a voltage divider network. Each button produces a different voltage level when pressed, and this voltage is read by the Arduino’s analog input pin (A0). Depending on the analog value detected, the Arduino determines which button has been pressed and triggers the corresponding frequency on the piezo buzzer.

The buzzer is connected to a digital output pin (pin 8), and when a note is selected, the Arduino uses the tone() function to play the correct frequency. When no button is pressed, the noTone() function is called, stopping any sound output.

3. Circuit Description

• Arduino Board (Uno or Mega): The central controller that reads the analog signals and produces sound output.

• Breadboard: Used for prototyping the circuit without soldering.

• Four Push Buttons: Each button is assigned to a specific note (e.g., C, D, E, F).

• Resistors (10kΩ, 1MΩ, 330Ω): Used as pull-down resistors and to create distinct voltage levels for each button.

• Piezo Buzzer: Outputs the generated tones based on the pressed button.

• Jumper Wires: For connecting all components.

• USB Cable and Computer: For powering and programming the Arduino.

Figure 1. Implementation of the circuit on a breadboard with Arduino Mega, four push buttons, resistors, and piezo buzzer

Figure 2. Top view of the digital keyboard circuit showing the connection between Arduino Mega, push buttons, resistors, and the piezo buzzer

Figure 3. Circuit diagram of the digital keyboard with Arduino Uno, push buttons, resistors, and piezo buzzer created in Fritzing

4. Software Implementation

The program reads the analog input value from pin A0 and uses conditional checks to map each range of values to a specific frequency. A small array of notes {262, 294, 330, 349} corresponds to the frequencies of common musical tones. When a button is pressed, the program selects the correct note from the array and sends it to the buzzer.

This method is efficient because only one analog pin is required to handle multiple buttons, instead of using one digital pin per button. It introduces students to the concept of analog multiplexing and voltage division to expand input capabilities.

5. Educational Value

Through this project, students learn:

• How to read and interpret analog signals with Arduino.

• How to use conditional logic to trigger different outputs.

• How to generate sound and tones using the tone() function.

• The importance of resistors in controlling voltage and current in circuits.

• The process of designing an interactive prototype that responds to user input.

6. Conclusion

This simple digital keyboard project successfully demonstrates how microcontrollers can be used to create interactive electronic systems. By pressing the buttons, different musical notes are generated, providing both a fun and educational experience. Exercise is highly valuable for beginners in electronics and programming, as it combines theory with practice and encourages creativity in building new musical or interactive systems with Arduino.

Schematics

Code

Code for Digital Keyboard with Sound Output

int notes[] = {262, 294, 330, 349};

void setup() {
  Serial.begin(9600);
}

void loop() {
  int keyVal = analogRead(A0);
  Serial.println(keyVal);

  if (keyVal == 1023) {
    tone(8, notes[0]);
  } else if (keyVal >= 990 && keyVal <= 1010) {
    tone(8, notes[1]);
  } else if (keyVal >= 505 && keyVal <= 515) {
    tone(8, notes[2]);
  } else if (keyVal >= 5 && keyVal <= 10) {
    tone(8, notes[3]);
  } else {
    noTone(8);
  }
}

Credits

Rexhep Mustafovski

2 projects • 3 followers

An Officer and a Teaching and Research Assistant at the Military Academy "General Mihailo Apostolski" - Skopje.

Build an Arduino Keyboard that Plays Real Notes

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Digital Keyboard with Sound Output using Arduino

Custom parts and enclosures

Digital Keyboard with Sound Output using Arduino

Schematics

Fritzing Circuit Diagram – Digital Keyboard with Arduino

Code

Code for Digital Keyboard with Sound Output

Credits

Rexhep Mustafovski

Comments

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Build an Arduino Keyboard that Plays Real Notes

Build an Arduino Keyboard that Plays Real Notes

Things used in this project

Hardware components

Software apps and online services

Hand tools and fabrication machines

Story

Digital Keyboard with Sound Output using Arduino

Custom parts and enclosures

Digital Keyboard with Sound Output using Arduino

Schematics

Fritzing Circuit Diagram – Digital Keyboard with Arduino

Code

Code for Digital Keyboard with Sound Output

Credits

Rexhep Mustafovski

Comments

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