hakoru-tuner-two ⚡ Real-time tuner module for React Native (Expo) apps.

Uses native AudioRecord + YIN pitch detection. Supports calibration (A4=440Hz etc.) Emits pitch + note + cents info live to JS. Currently supports Android only.

Installation npm install hakoru-tuner-two

⚠️ Requires a custom Expo dev client build. Setup for Expo

Add the module to your project: npm install hakoru-tuner-two

Add microphone permission to app.json: { "expo": { "android": { "permissions": ["RECORD_AUDIO"] } } }

Create a custom dev client: eas build --platform android --profile development

Run your app with the dev client: expo start --dev-client

Permissions This module requires the RECORD_AUDIO permission. You can request it using expo-av (recommended for Expo SDK 49+) or expo-permissions: // Using expo-av import { Audio } from 'expo-av'; const { status } = await Audio.requestPermissionsAsync();

// Using expo-permissions (for older SDK versions) import * as Permissions from 'expo-permissions'; const { status } = await Permissions.askAsync(Permissions.AUDIO_RECORDING);

Usage import { Audio } from 'expo-av'; import { start, stop, onPitchDetected } from 'hakoru-tuner-two';

async function startTuning() { const { status } = await Audio.requestPermissionsAsync(); if (status !== 'granted') { console.log('Microphone permission denied'); return; }

const subscription = onPitchDetected(({ freq, note, cents, isInTune }) => { console.log(Frequency: ${freq}Hz, Note: ${note}, Cents: ${cents}, In Tune: ${isInTune}); });

try { await start({ a4: 440 }); } catch (error) { console.error('Failed to start tuning:', error); }

// Later, stop tuning // stop(); // subscription.remove(); }

startTuning();

API

start(options?: { a4: number }): Promise - Starts the tuner with optional A4 frequency (default: 440Hz). stop(): void - Stops the tuner. onPitchDetected(callback: (data: PitchResult) => void): { remove: () => void } - Subscribes to pitch detection events.

PitchResult interface PitchResult { freq: number; // Detected frequency in Hz note: string; // Note name (e.g., "A4") cents: number; // Cents offset from the target note isInTune: boolean; // Whether the note is in tune (within ±5 cents) }

Notes

Ensure you have a custom Expo dev client for Android. Microphone permission is required for the module to work. iOS support is not yet available.

License MIT