Google's AIY products were an experiment to bring a hands-on building experience to retail storefronts. It's the kind of thing one would expect to find at Radio Shack, if Radio Shack were still alive. Sadly, with the AIY Voice kit marked down for clearance at my local Target, the experiment did not appear to be a resounding success. Still it means I now have a Google AIY voice kit to play with.

Just for the sake of seeing how it was supposed to come together, I followed assembly instructions even though I had no interest in building my own Google voice assistant for my home. Or at least, I got it set up far enough to have the mechanical box on my home network. I stopped before completing the steps to sign up for Google Assistant API access and enrolling this piece of hardware.

What it means is that I now have a Raspberry Pi Zero on my home network, coupled with "Voice Bonnet" audio hardware that I can now learn more about.

Google AIY Voice Bonnet

It appears all the code to interface with this Voice Bonnet is documented and available online. I went straight to the aiy.voice.audio APIs to see how one interacts with the audio capabilities. I had expected to find code interfacing with device drivers and hardware registers, I didn't expect that the source file mostly consists of code that calls out to standard command-line audio utilities arecord and aplay.

I then looked into the default text-to-speech capabilities inside aiy.voice.tts and found much of the same: text is sent out to a command-line utility pico2wave which does all the hard work. It generates a sound file, which is then sent to aplay for playback.

This is great news: this meant it will be trivial to use the audio recording and playback capabilities of this Voice Bonnet for purposes other than interacting with Google voice assistant platform.