Hi am Kyaw thiha i would like to get details on electronic school bell using 8051 code ..My friend Nyan Bxone said electronic school bell using 8051 code will be available here and now i am living at ......... and i last studied in the college/school ......... and now am doing ....i need help on ......etc

pls give me school bell circuit using 8051.

We are living in the world of automation where all the activities are getting automated through the use of advanced programmable controllers in home automation and industrial automation systems. An automatic school timer system reduces the effort needed to turn on or off an electric bell manually that gives alarm for certain intervals of time based on school timings. This automatic system is a microcontroller based project that uses a simple basic microcontroller, which makes this product affordable.

Usually conventional methods require a peon or bell operator to attend and operate the bell system for every period and interval in schools and institutions. Such systems need sufficient human efforts to do so, and require advancement in order to become automated – the ones that minimize human efforts. As the bell system is important in schools, homes and industries, automatic operation of this instrument must have to be performed with a precise time controller in an economical way.

This automatic school bell timer system is designed using basic 8051 microcontroller for managing time intervals. Read or Write memory is also necessary for storing bell timings, but for less number of timings this memory is not needed. This system also provides the display of timing information in seven-segment display for a user interface purpose.

This system uses a power-supply block to drive all the circuit components, an 8051 microcontroller to control and manage bell timings, a real-time clock for accurate timing operation, a matrix keypad to enter and configure the bell timings and a seven-segment display to display the time and information. The operation of this system can be easily understood from the above block diagram, wherein the keypad entered timings are stored in the microcontroller, which are responsible for operating the bell based on the program of the microcontroller.

Microcontroller based School Timer Circuit Operation

The Regulated DC power supply is given to the microcontroller using a power-supply block (In the circuit, it is not given but given in the block diagram). This power-supply block consists of a step-down transformer, a bride rectifier, a filter and a regulator IC. The mains 230V supply is stepped downed to a 12V AC by using the transformer. This AC is rectified to a DC supply by the bridge rectifier and capacitor filters to a pure DC, and then by a regulator that regulates the power to a constant DC to 5V. This power supply drives the entire circuit except the relay and bell devices.