Sound detection

Hello, I'm new to arduino, but I have a project in mind and I want to know if it's possible to build it using arduino. the goal of project is to get an email every time my house door lock is being locked/unlocked. The only way I found out to do it is using sound detection. Is there a way to detect a certain sound using arduino ?

use an elect. microphone - -
if a threshold is passed call the code to send a mail - no example, sorry -

just saw this one - -

Detecting particular types of sound may not be easy. Your best approach would probably be to attach the mic to the door, so that the sound of knocking is the loudest sound. Even them, if you live in a noisy neighbourhood or next to a train line or major road, those sounds could be as loud as a knock on the door.

You are probably off using a door bell, possibly a wireless door bell if you can't drill a hole etc for the push button.

Sending the email is another slight hurdle, it is definitely possible, but implies either a wifi or hard wired Internet connection.

Post again if you are going ahead with this and people can give you more details of the email side of things