Objective C - detect sound

How can I detect sound on the iPhone?

I currently have it somewhat working using the method described in this article http://mobileorchard.com/tutorial-detecting-when-a-user-blows-into-the-mic/

However, as mentioned in that article, in noisy rooms for example, the method won't work.

So in a way, I'm looking for methods tha开发者_如何学JAVAt I can use to separate background noise from actual noise intended?

There probably won't be an existing code on the internet, but if someone can point me to the right direction, it would be very appreciated.

Thank you,

Tee

It's definitely not a great solution, but you could determine a baseline amplitude (ambient sound) and trigger your events when you determine that the amplitude is a certain amount greater for a set amount of time.