Godot Note Pitch Detector Addon ♪

Adds a NoteDetector node that emits signals when it detects musical notes from the microphone.

Useful for creating musical games, interactive toys, visualizers, etc.

Prerequisites

Enable the addon in the project settings:

Project Settings > Plugins > Enable 'Note Pitch Detector'

You also need to enable audio input:

Project Settings > Audio > Driver > Enable Audio Input

Make sure to select the audio input device you want to use. By default, the addon selects the system's default audio input device (device 0).

# Get a list of strings representing the available audio devices
# You can put this in a UI to allow the user to select the input device
var devices = AudioServer.get_input_device_list()

# Set the audio input device
AudioServer.input_device = devices[0]

Usage

Place a NoteDetector node in your scene and connect the signals to your own logic.

@onready var note_detector = $NoteDetector

func _ready() -> void:
  note_detector.detect_note_started.connect(on_note_started)

func on_note_started(event: NoteDetectEvent) -> void:
  print("Note detected: ", event.note_name)

Detection Algorithm

Note detection is always monophonic, meaning it only detects one note at a time.

The addon uses autocorrelation by default. This is a fast and simple algorithm that works well for most instruments, but may pick up silence and noise as notes. You can optionally use YIN, which might be better for voice, wind instruments, etc.

PitchDetectorServer.algorithm = PitchDetectorServer.Algorithm.YIN

Read more: https://www.hyuncat.com/blog/yin/

API

Node Properties

• threshold: The duration (in milliseconds) a note has to be sustained before the detection signal is emitted.
• release: The duration (in milliseconds) a note has to be released before the detection signal is emitted.
• grace_period: The duration (in milliseconds) a note can be "not detected" during buildup before the buildup is cancelled.
• transpose: The number of semitones to transpose the detected note.

Signals

• detect_note_started(event: NoteDetectEvent): Emitted when a note is detected.
• detect_note_stopped(event: NoteDetectEvent): Emitted when a note is no longer detected.
• detect_started: Emitted when the note detector starts detecting notes (after silence).
• detect_stopped: Emitted when the note detector stops detecting notes (silence).

NoteDetectEvent

• note_name: The name of the note (e.g. "C", "C#", "D", etc.).
• note_full_name: The full name of the note (e.g. "C#3", "D4", etc.).
• note_index: The index of the note (0 = C0, 1 = C#0, 12 = C1, etc.).
• note_octave: The octave of the note (0 = C0, 1 = C1, etc.).