This adds a plugin for pocketsphinx, this is the fallback mycroft wake word engine and is supported out of the box by core, however I have some issues with the official implementation that I try to solve with this

• does not require setting phonemes, this plugin will guess them automatically
• allow setting your own acoustic model, mycroft-core only bundles the english model
  • to change language you need to modify mycroft-core
  • core wont take PRs for new language models
  • by default this package uses english model from speech_recognition package, which is a requirement of mycroft-core
  • mycroft-core bundles it's own model which is unnecessary
• allow overriding recording of wake words time, this is derived from number of phonemes and sometimes inadequate

The "plugins" are pip install-able modules that provide new engines for mycroft

more info in the docs

pip install ovos-ww-plugin-pocketsphinx

Configure your wake word in mycroft.conf

 "listener": {
      "wake_word": "andromeda"
 },
 "hotwords": {
    "andromeda": {
        "module": "ovos-ww-plugin-pocketsphinx",
        "threshold": 1e-45
    }
  }
 

Advanced configuration

You can get acoustic models from sourceforge

NOTE: it might be useful to use an acoustic model from a language that is not your own and set phonemes manually, eg, spanish model works just fine for portuguese

 "listener": {
      "wake_word": "dinossauro"
 },
 "hotwords": {
    "dinossauro": {
        "module": "ovos-ww-plugin-pocketsphinx",
        "threshold": 1e-20,
        "phonemes": "d i n o s a u r o",
        "hmm": "/path/to/sourceforge/es-es/hmm/",
        "expected_duration": 2
    }
  }
 

• threshold defaults to 1e-30, there is no good default value and this is arbitrary, to increase the sensitivity, reduce the threshold. The threshold is usually given in scientific notation.

• hmm path to your own acoustic model

  • you might need to change lang if using your own model
  • you might need to set phonemes manually if using unsupported languages

• lang override language, by default the global lang set in mycroft.conf is used

  • this value is used to guess phonemes
  • if lang is not english, you need to set hmm because no model will be loaded
  • if phonemes is not set and lang is unsupported, an exception will be raised

• phonemes the phonemes corresponding to the wake word. If your wake word phrase is more than one word, remember to include a period (.) between words.

  • this plugin uses the phoneme_guesser package to set phonemes
  • most of the time you only need to set the phonemes to improve accuracy, especially for out of vocabulary words (not present in the .dict files)
  • the number of words in keyword (split by " ") must match the number of words in phonemes (split by ".")
  • lookup phonemes by inspecting the .dict files for similar words
  • phonemes depend on acoustic model used, there are several Notational Systems

• expected_duration defaults to 3 seconds (max value), this is the time used for saving wake word samples