I know it’s been an issue on some of the courses so far that Google Hangouts have started to mute the mic when a user is typing. This makes a live typing demo / screencast pretty difficult. You might try using an iPad with the Hangouts app. I haven’t fully thought through the implementation of how it could work, but I do know that it can’t detect your computer typing and mute you.
Hmm. That’s good to know. Too bad it’s not a feature you can turn on or off.