Doing DSP in your phone or other android device might become really difficult, really fast. In any case, I'd recommend that you get one of those development boards which runs Android and work with that to start. No need to sacrifice your phone ahead of time. Also, instead of listening for sounds, maybe you can wire up a dedicated device into the home which would talk directly to the haptic device or the glasses? My brother went to RIT (Rochester Institute of Technology) and they have a large deaf population there, to the extent that some dorms are fitted out with the bright stobe lights used to wake/alert deaf people of fire alarms, etc. Listening for arbitrary sounds and trying to match them to a library of triggers sounds (sorry for the pun) like a very hard problem. Even apple is doing Siri by sending your speech to a remote datacenter for processing, since the phones don't have enough juice. Admittedly, that's a more difficult problem space, but it is similar and less open ended than your problem space. Just hooking an Arduino into my doorbell/phone/other sensors and having the arduino talk to the alerting system might be a simpler way to do it. John