Automatic School Bell

Jahanzeb Gul
jahanzebgul89@gmail.com
47.161 Views
medium
Non tested
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Description

This project is an Automatic School bell system. Such a system triggers a bell (or operates any other load) at predifined time. In this version some advanced features are introduced:

16×2 LCD Display ( Displays current date, time and day)
4×4 Keypad for Inputs
Stand alone product ( no PC required to program or maintain ringing schedule)
No battery required to maintain clock and ringing schedule
Variable ringing time
Max 10 bells can be set
Custom Weekend filters
Monthly OFF / Weekly OFF
Half Day
Total AC Power Handling : 1000W (240V 5A)
Connect as many AC electronic bells in parallel form
Built-in back up battery supply
Built in permanent memory for bell timings
Auto-memory scan on system startup

I used PIC18f4520 microcontroller as the brain of the system. RTC1307 IC is used to maintain the clock,date and day with a 3V backup voltage battery. Bell timings are stored in the internal EEPROM of mcu.

MCU is reading time from RTC through I2C Serial protocol and compares the current time with stored memory time in a continous while(1) loop.

MM74C922 decoder IC is used for keyboard. Reading the sixteen buttons is done using 4-bits output of decoder IC.