Consulting on doorbell watcher with tape recorder.

Halloy guys..!
As I'm a bigginer on electronics design I need some help from you.
I planning to design a system which allow a person to monitor through a tape recorder if someone has rung his home doorbell when he leaves the house for a few hours or a week end, when a person rung the doorbell, the system will tell him to leave the voice message through a microphone and that message will be recorded in a tape through the tape recorder.When the person back to his home place is going to get information by risen the tape. On this design i have already completed a system block diagram which consist of doorbell, switch,amplifier, memory chip and tape recorder.
But on the system, i would like to know
1-A complete circuit diagram for the whole system
2-the connection of the switch to the memory chip and the tape
recorder that can sense a signal from a doorbell when a person
rung a bell and when a person start talking through a microphone
in order to leave a message respectively.
3- A program that can be easy for me to store the message in the
memory chip.

I first forward my appreciation to your help.

Regards
Gombo :lol:

to detect if someone pressed the switch us an SCR and an LED.