Ringing a school bell manually or relying on a clunky mechanical timer is decidedly old school. You can use this simple, modern school bell timer circuit instead.
Probably since the time schools came into existence school bells were used in the system, an indispensable piece of equipment for every school.
They are basically a mechanical device that is able to produce a loud and sharp sound under the influence of an external applied force. The function of a school bell has fundamentally remained the same since the beginning – to divide the class periods into equal parts and indicate their start and finish with a distinctive sound.
This type of bell has slowly been replaced by more efficient electric bells and they are in use even today in most schools for the same purpose.