On a related note, check this project out. http://jasperproject.github.io/

You can perhaps trigger alexa to start listening through it by wiring the voice recognition to click the "start listening" button.

Jasper is outdated and incredibly difficult to install on any recent model (2, 3 or 0).

yes this is what I came into say. You can hardwire a phrase similar to how jasper does it and use that to trigger the start listening method

This actually sounds more like my ideal.

I've heard the anecdotes about Alexa responding erroneously when people weren't home and doing things like turning the furnace on, etc. That combined with the general privacy concerns make me much more comfortable with being able to push a button to get her to listen – but I'd rather it be a button on my person – like on my fitbit, watch, etc. – easy, always available – plus maybe a way to turn it on for listening over a duration – say while cooking.

Haven't tried it yet, but I hear Pocketsphinx has a keyword spotting mode.

https://github.com/cmusphinx/pocketsphinx

Look into OpenEars. It's pretty crummy but it's free :/

i wrote a simple clap trigger (using the raspberry micro) that is always listening. I use it to shuffle my phillips hue light but it can easily be used to trigger echo voice https://github.com/131/clap-trigger

I'm imagining carrying around a little bell.

I have Blather configured to do various key-presses and so control pentadactyl and so control firefox.

It could be set up to provide whatever signals a button can provide.

http://www.jezra.net/projects/blather

I think part of the terms for the Alexa voice service forbid auto-listening.

You could use a bluetooth remote with 1 button or so to trigger that listening. I don't think the RPI is powerful enough to do voice recognition.

It is indeed for a limited number of phrases! I have used it that way for at least 2 years with Jasper and PocketSphinx

I wish I could go one step further and instead of even having a mic on the device, use a web app on my phone to record and send the audio to the pi