tone-stream

Overview

A simple node.js tone stream library.

You can specify frequencies to be played by adding items in the format:

  [NUMBER_OF_SAMPLES, FREQUENCY]

or DTMF tones:

  [NUMBER_OF_SAMPLES, 'DTMF:ID']

You can add multiple of such tones and they will be enequeued and played in order.

Installation

npm i tone-stream

Sample usage

Playing some musical notes:

const { ToneStream } = require('tone-stream')

const Speaker = require('speaker')

const sampleRate = 8000

const format = {
  sampleRate,
  bitDepth: 16,
  channels: 1
}

const ts = new ToneStream(format)

const s = new Speaker(format)

var ns = 0
ns += ts.add([1000, 261.63]) // C4
ns += ts.add([1000, 296.33]) // D4
ns += ts.add([1000, 329.63]) // E4

var duration = ns / sampleRate * 1000

ts.pipe(s)

setTimeout(() => {
  console.log("done")
  process.exit(0)
}, duration)

Playing some DTMF tones:

const { ToneStream } = require('tone-stream')

const Speaker = require('speaker')

const sampleRate = 8000

const format = {
  sampleRate,
  bitDepth: 16,
  channels: 1
}

const ts = new ToneStream(format)

const s = new Speaker(format)

var ns = 0

ns += ts.add([1000, 'DTMF:1'])
ns += ts.add([500, 's'])
ns += ts.add([1000, 'DTMF:2'])
ns += ts.add([500, 's'])
ns += ts.add([1000, 'DTMF:3'])
ns += ts.add([500, 's'])

var duration = ns / sampleRate * 1000

ts.pipe(s)

setTimeout(() => {
  console.log("done")
  process.exit(0)
}, duration)

Using some helper function to add miscelaneous tones

const { ToneStream, utils } = require('tone-stream')

const Speaker = require('speaker')

const _ = require('lodash')

const SAMPLE_RATE = 8000

const format = {
        sampleRate: SAMPLE_RATE,
        bitDepth: 16,
        channels: 1
}

const ts = new ToneStream(format)

const s = new Speaker(format)

const tones = _.flatten([
    utils.gen_dtmf_tones("1234567890abcdef", 100, 100, SAMPLE_RATE),
    utils.gen_morse_tones("Be yourself; everyone else is already taken", 880, 70, SAMPLE_RATE),
    utils.gen_music_scale("C5 D5 E5 F5 G5 A5 B5 C6", 100, 0, SAMPLE_RATE),
])

console.log("Inspecting tones:")
tones.forEach(tone => {
    console.log(tone)
})

ts.concat(tones)

ts.on('empty', () => {
    console.log("Got event 'empty'. Reversing tones and playing again.")
    tones.reverse()
    ts.concat(tones)
})

console.log("Starting playing tones")
ts.pipe(s)

Events

The stream emits events:

• 'empty': when there are no more tones to be played in the queue (it happens when the queue of tones is found empty)
• 'ended': when all tones in the queue were generated (it happens when the consumer tries to read data from the stream and there are no more tones to be generated)

More examples

See here.