I'm looking for a sort of trigger in Android, that would let me perform a task whenever a sound is played, so for incoming calls, SMS and e-mail notifications. I did find something like this, but it's only for when the phone is called:
http://developer.android.com/reference/android/telephony/TelephonyManager.html
What I want to achieve with this is sending a bluetooth signal to a bracelet, so it starts vibrating. This would be suited for the hearing impeared or people that work/live in a loud environment who don't carry their phone attached to their bodies.