How about using a microphone and some sort of audio level sensor?
I've got fans generating a lot of noise. so that is not going to work.
Quote from: Ufoguy on Jul 04, 2013, 04:09 pmI've got fans generating a lot of noise. so that is not going to work.What's the purpose of knowing when they're speaking? This might give a clue to sensible ways to achieve it. For example, if you ultimately want to hear what was said, perhaps a throat mike or noise canceling mike would make sense.
...Moderator edit: Facile cheap-shot elided.
please suggest something else.