Design a digital circuit that can be attached to a school bill which can work automatically from 7:00 AM to 12:45 PM, and it has the following features:
1- Rings for 5 seconds.
2- Start ringing 7:00 AM to announce for the field gathering.
3- Rings 7:20 for going to class.
4- Rings for the start of the first class period at 7:35 AM.
5- Rings for end of each period after 40 minutes from its start.
6- Rings for break after 10 minutes from the end of the previous period to announce for the next class period.
7- After the third period, a break of 30 minutes