basic microphone for nodejs (linux)

README.md

Requirements

• arecord: sudo apt-get install alsa-utils
• lodash: npm install lodash

Usage

const Microphone =  require('./path/to/microphone');
const mic = new Microphone();
mic.pipe(someWritable);
setTimeout(() => mic.stop(), 5000);

microphone.js

// @flow
'use strict';
const PassThrough = require('stream').PassThrough;
const spawn = require('child_process').spawn;
const _ = require('lodash');

type Options = {
  channels?: number,
  sampleRate?: number,
  endianness?: 'LE',
  byteRate?: 16
};

class Microphone extends PassThrough {
  _proc: Object;
  constructor (options?: Options) {
    super();
    options = _.defaults(options || {}, {
      channels: 1,
      sampleRate: 16000,
      endianness: 'LE',
      byteRate: 16
    });
    this._proc = spawn('arecord', [
      '-q',
      '-c', options.channels,
      '-r', options.sampleRate,
      '-f', `S${options.byteRate}_${options.endianness}`,  // S=signed, 16bits, little-endian,
      '-t', 'raw'
    ], {
      stdio: [ 'ignore', 'pipe', 'ignore' ] // pipe stdout only
    });
    this._proc.stdout.pipe(this);
  }

  stop () {
    this._proc.kill();
  }
}

module.exports = Microphone;