INTRODUCTION
In today’s life, everyone gives importance to time. Time does not wait for anybody. Everything should be performed in time & accurately. Now a day’s school/college bells are manually operated. Hence there is a big question of accuracy. Also there is necessity of manpower and money. Hence here we should use automatic control system, which saves our manpower and money & also highest accuracy. Hence we have selected t ....etc

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Abstract:
in this project we set the interval time and buzzer time through keypad. An internal clock will run inside the controller which will turn on the buzzer at the desired time periods. PC interface is provided so as to send the data to the computer and viz versa

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this project is is an embedded System That can be built to automatically Ring the bell At various intervals(needs timer circuit) according to user need and must be programmable by user for working days and this device need to work in two modes
1.normal mode (where it ring the bells automatically without any human intervention)
2.emergency mode(this mode is use to stop the bell or rang the bell manually ) ....etc

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Here is a musical call bell that can be operated by just bridging the gap between the touchplates with one’s fingertips. Thus there is no need for a mechanical ‘on’/‘off’ switch because the touch-plates act as a switch. Other features include low cost and low power consumption. The bell can work on 1.5V or 3V, using one or two pencil cells, and can be used in homes and offices. Two transistors are used for sensing the finger touch and switching on a melody IC. Transistor BC548 is npn type while transistor BC558 is pnp type. The emitt ....etc

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im dasrath mHATO, NOW I M STUDY IN DIPLOMA ELECTRICAL ENGG. I WANT IDEA ABOUTAutomatic School Bell with user defined time schedule using 12C PROTOCOL.
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GOOD EVENING SIR,

I'm deepak studying dip.electronics and communication engneering here i would like to know more about the project named microcontrolled automatic college bell with announcment ....etc

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hai
i need document regording school bell ....etc

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am searching for a self driven bell timer circuit diagram. I want to open my own company for bell installation. In future i will be using the internet to control the bells. ....etc

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Pile driving at large construction sites produces formidable noise. Marine pile driving similarly can produce high sound pressures underwater”but these can be lethal to fish and can harass marine mammals, including those protected by federal law. This problem has contributed to costly construction delays on major bridge projects. To protect marine life, engineers have designed air bubble curtains to reduce underwater sounds. Air provides an effective barrier to sound propagating through water, because of the difference in density betwee ....etc

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this is pcb layout for automatic college bell( based on AT89S8252&DS1307). but this is in reduce size. so i want the new pcb layout for automatic college bell which is in exact size. ....etc

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