Well, that will imply that anyone using the doorbell has got a steem account. We are almost there, but not yet fully :) Nevertheless, what it could be (more or less easily done), is to write a post everytime someone hits the button. Something like:

Gargon Doorbell: 23.11.16 07:30.

With a couple of sensors, we could also insert an:

Gargon Doorbell activtated: 23.11.16 07:30.
Outside temperature: 13°Celsius
Inside temperature: 22°Celsius
Relative humidity: 95%.
Air Presure: 760.00 mmHg

Perhaps a quick photo of the one standing at the door? Ups -> Ill guess well have some privacy issues here..

lol