Lowwi - Lightweight openwakeword implementation written in C++.

Wakeword detector based on OpenWakeWord-cpp but faster, cleaner and more lightweight.

• Plain C/C++ implementation with minimal dependencies (ONNXRuntime)
• Runs on ARM as well (Tested on RPI 3,4 and 5)
• Written with performance in mind, < 3% CPU utilization on x86/64 CPUs

API Features

This library offers support for:

• Single-model wakeword detection
• Multi-model wakeword detection

Single-model wakeword detection

This is some example code for wakeword detection:

...
 /* Create new Lowwi runtime */
CLFML::LOWWI::Lowwi ww_runtime;

/* Create new wakeword */
CLFML::LOWWI::Lowwi_word_t ww;
ww.cbfunc = wakeword_callback;
ww.model_path = "models/example_wakewords/hey_mycroft.onnx";
ww.phrase = "Hey Mycroft";
    
/* Add wakeword to ww-runtime */
ww_runtime.add_wakeword(ww);

std::vector<float> audio_samples;
...

while(1) {
    ww_runtime.run(audio_samples);
}

Multi-model wakeword detection

Just create two or more Lowwi_word_t's:

...
/* Create new wakeword */
CLFML::LOWWI::Lowwi_word_t ww;
ww.cbfunc = wakeword_callback;
ww.model_path = "models/example_wakewords/hey_mycroft.onnx";
ww.phrase = "Hey Mycroft";
    
/* Add wakeword to ww-runtime */
ww_runtime.add_wakeword(ww);

/* Create new wakeword */
CLFML::LOWWI::Lowwi_word_t ww2;
ww2.cbfunc = wakeword_callback;
ww2.model_path = "models/example_wakewords/hey_jarvis.onnx";
ww2.phrase = "Hey Jarvis";
    
/* Add wakeword to ww-runtime */
ww_runtime.add_wakeword(ww2);

Example code

For a full example showcasing the API functions see the example code in example/LOWWI_demo_mic/demo.cpp.

Building with CMake

Before using this library you will need the following packages installed:

• Working C++ compiler (GCC, Clang, MSVC (2017 or Higher))
• CMake
• Ninja (Optional, but preferred)
• SDL (when using Lowwi mic example)

Running the examples (CPU)

1. Clone this repo
2. Run:

cmake . -B build -G Ninja

3. Let CMake generate and run:

cd build && ninja

4. After building you can run (linux & mac):

./LOWWI_demo

or (if using windows)

LOWWI_demo.exe

Using it in your project as library

Add this to your top-level CMakeLists file:

include(FetchContent)

FetchContent_Declare(
    Lowwi
    GIT_REPOSITORY https://github.com/CLFML/lowwi
    GIT_TAG main
    SOURCE_DIR ${CMAKE_CURRENT_LIST_DIR}/lib/Lowwi
)
FetchContent_MakeAvailable(Lowwi)
...
target_link_libraries(YOUR_EXECUTABLE CLFML::Lowwi)

Or manually clone this repo and add the library to your project using:

add_subdirectory(lowwi)
...
target_link_libraries(YOUR_EXECUTABLE CLFML::Lowwi)

Aditional documentation

See our wiki...

Todo

• Add language bindings for Python, C# and Java
• Add support for MakeFiles, Bazel and Conan
• Add Unit-tests
• Add TPU support
• Add automatic wakeword training
• Merge melspectrogram & embedding model?

License

This work is licensed under the Apache 2.0 license.