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automatic school siren controller

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Newbie level 3
May 7, 2011
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i ma looking for a complete (with schematic diagrams ) project of an automatic school siren (bell) controller which can be programmed 40 to 50 different events (times) per day .which should display day, date ,time, and year ,preferably with password protection. power source should be 12V DC or 220v AC. please use e-mail
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use a PC connected to a relay card, the connection can be either thru RS232 port, or parallel port of more relays are needed.

The advantage here is that....

1. Any PC from the school's computer department can be used for this task (though access to it must be restricted).

2. PC based software are easy to design. You can have more than 40-50 events in this case. The interface is easy design using VB or Delphi. The events can all be linked to a database that is very easy to manage. Perhaps a web-interface can also be used if required. All these can be designed and made by a VB/Delphi programmer.

3. The relay card is a simple affair, just one or two relays connected via opto-isolators to the RTS and DTR pins of the RS 232 port. Since only the relay needs to be switched ON/OFF no PIC or micro-controller is needed, thus eliminating programmer/firmware programming task.

4. No need to bother about date/time management as PCs have very reliable and accurate RTC.
The PC can be switched ON in the morning before the school opens. The application can be run in the startup.

If you are designing this for someone then try to convince him/her about the advantages of using a PC based system instead of a standalone one.
But if you are making this for a school project then I guess you can't the original project specs.


i am looking for assistance sir not buying.

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i need a stand alone type because most of the time there is no electricity at the school

Check this site

**broken link removed**

the link provided by drbizarow did not meat the requirements. what is needed is a simple circuit

the link provided by drbizarow did not meat the requirements. what is needed is a simple circuit

ok then do some effort .......... noone exactly meet your requirement or do it for you what you want.........Simple!!!.

I know that from may, 2011 pass many classes to now, but see this project:

Microcontroller-Based School Timer

For more information register and get complete EFY project with source code, PCB, and project document info. Registration is free.


• Precise time base for time keeping.
• Read/write memory for storing the bell timings.
• LCD or LED display for displaying real time as well as other data to make the instrument user-friendly.
• Keys for data entry.
• Electromechanical relay to operate the bell.
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