PiHueSphinx

A simple C# program using pocketsphinx to control Phillips Hue lights using voice commands. I run this on a Raspberry Pi in my home.

aka. my cheap Alexa

Building

Provided you have installed a recent pocketsphinx library, you should be able to build everything from the IDE or via xbuild/msbuild.

By recent pocketsphinx library, that would usually mean going to http://cmusphinx.sourceforge.net/wiki/download and building the last version from there as your distribution packages likely haven't caught up.

If the C compilation fails, you can adjust properties and stuff at the end of the PiHueSphinx.csproj file to make sure it's finding your copy of libpocketsphinx.

Usage

PiHueSphinx.exe CONFIG HOTWORD ALSA_INPUT_DEVICE [HUE_API_KEY]

Example: mono --debug PiHueSphinx.exe pocketsphinx.conf "OKAY RASPBERRY" "plug:usb" "<Your Hue API Key>"

If you want to change the hotword it needs to be part of your corpus and the language model needs to be re-generated, see section below.

The ALSA input device can be whatever ALSA supports, in my case it's a USB camera from which I use the microphone. Refer to ALSA documentation to learn how to setup an input device. Your device might need a different input sampling rate that you can change in the pocketsphinx.conf file.

Once the program has associated with your Hue bridge and generated an app key (it will print it on the console), you should start passing it as the last argument.

Generating pocketsphinx language model

The corpus.txt file contains the list of command that the program processes.

The pisphinx.lm and pisphinx.dic files were generating from that corpus.txt file using their online service at http://www.speech.cs.cmu.edu/tools/lmtool-new.html

Calibrating the program

The pocketsphinx.conf file contains the configuration used by pocketsphinx. In it you have the -kws_threshold parameter which is a little obscure in every tidbit of documentation that I went through.

The value there depends on your hotword command (in my case "Okay Raspberry") and it's basically by trial and error that you can find a good one. Try to go from 1e-1 to 1e-60.

Phillips hue API key

When you run the program it will locate the Phillips base station using host discovery. If you haven't passed an API key on the command-line it will try to register itself for one, be sure to press the link big button on top of the station when that happen.

Libraries used

• Pocketsphinx: https://github.com/cmusphinx/pocketsphinx
• Q42 Hue API: https://github.com/Q42/Q42.HueApi

License

Code is placed under the Apache 2.0 license