Arduino components for smartening my current doorbell I would like to modernize my current (dumb) doorbell with arduino but as this is my first project, I need some advice on what I need to accomplish this :)

So, currently I own only Raspberry Pi 3 and I plan on using openHAB on it. My current doorbell is actually an intercom so it has two different bells (one for the call and second for the bell), it has a door opener button and thats about it. My intention is to be able to mute both bells (every bell its own switch), be able to receive some kind of notification (sms/email/whatever) in case  the bell event happens, and finally, to be able to simulate a door open button via mobile. 

As my RasberryPi is dislocated from the location of the intercom where this project should be placed, I would need to have some kind of wireless communication (do I need a wifi that should be connected to my router or I could be using some other kind of wireless connection [radio, bluetooth]?).

What would you reccomend for this project (components should be as small as possible and its resources should only be sufficient for this purpose).
Because you asked for recommendations I would like to recomment the solution I have at home for some years:


Auerswald doorbell speaker sorry for german product description - the a/b is important so that you could use it as analoge phone on 2! You also need a transformator as you should already have for your doorbell.
AVM Fritzbox router
Doorbell or not ....
Two Sipgate (or similar) VOIP accounts


After configuring your fritzbox router and your android phone, your phone will ring and you could talk to the person in front of your door werever you are on this planet ;-)

Just my recommendation....