Entry System

Intro
We could have gone to Wilko and get a standard wireless doorbell right? Nope! We have a much more interesting solution.

Features:
 * When you enter it plays a member entered noise
 * When the doorbell is rung it plays a doorbell noise
 * Screens are displayed on the big TV above the door
 * Announces who has just entered.
 * Plays music

Name
This needs a catchy name. Something like Greetr/ChimeyMakeGoScreen/TheBigDong.

Function
When the doorbell button is pushed, the Pi in the door broadcasts an MQTT message announcing the button is pressed. The message is received on the Pi above the door, and the doorbell sound is then played through the speakers.

Above the door we have: Pi, running fullpageos that points to an Angular/Express app that shows the screens, and also listens for the MQTT commands. This then announces who is entering. Also on the Pi is Mopidy, a music service connected to Spotify. Password can be obtained from cone/Rossy/others who got it working. We also have an amp connected to the big speakers. In event of these failing, connect to the TV aux input. We also have a spinning light but due to a change in amplifier this is not used at present and needs to be wired in again.

ToDo

 * Wire in spinning light.
 * Easy addition of screens/notices.