GSM based Digital Notice Board using ARM microcontroller

Project Title: GSM based Digital Notice Board

1.1 Motivation
From the past many years we are seeing the notices of the college , companies ,offices is usually displayed on the normal board having number of notices written on the same board .So we were thinking that if all these notices are displayed at the same place one by one except occupying the whole board area.
So we come to the conclusion to design a Notice board such that it can fulfill the requirements such as less manual operation, same notice can be displayed at the various places at the same time, the notice (board display) should be visible from maximum area or distance, compact and compatible, easy handling.

1.2 What is Digital Notice Board System?
It is a system having digital notice board. The notice can be displayed on the digital display in the rolling manner. The notice can be typed or edited on the PC. And then it will send the notice to every display connected to the system. Also we can receive the notice on Mobile phone through the GSM (wireless communication) Technology and display it on the digital display boards using the PC having the connectivity’s like Hyper terminal/AT commands/VB software.
In this way we can save the work as required for a regular notice board.

Fig.1.1 Plan view for college Digital Notice Board System

*) Digital input
Message received from mobile phone
Message typed on the PC(computer)
*) Power supply: From AC mains or battery backup to drive circuit.

*) Alphanumeric Display : – To display different messages.
*) LED: – For different types of indication.
*) Interfacing protocol RS-232:- For transferring the data to pc.
*) Interfacing protocol RS-485:- For transferring the data from pc to displays at long distances.



Fig.2.1 Block diagram of Digital Notice Board System.

2.2 Block Diagram Description:

In our project we are going to demonstrate the Digital Notice Board system using rolling display .Also we are going the SMS/GSM technique as an additional feature to the system.
The blocks shown in the diagram are described as below:

2.2.1 Dedicated mobile:-
In our day today life we know most of the peoples used the mobile phones .The peoples used the phones to achieve or to get the different facilities .The mobile phone can provide the different facilities such as SMS,GPRS,MMS,VOICECALLS,DATA CALLS, GPRS, Entertainment flexibility in work.
Some of these facilities are useful in our project so we are using the SMS that is GSM techniques to transfer data from distant places such as from one area to the another area of the same city or from another city
In our project we are using SMS technique to instant or quick transfer of data or notice to the required destination that is college or department.
This above given use or function is provided by the dedicated mobile use in our digital notice board system.

2.2.2 PC:
We already know about the facility of the mobile, so after receiving data from the dedicated mobile we can copy or use the same data in our PC. The PC and dedicated mobile can be interfaced with the help of the data cable DKU-50.
We are using the VB software in our PC for the user interface with the system. With the help of this VB software any user can easily make the use of the system.
This VB software provides the notice typing and editing facility. Also we can copy the same content as received through mobile in the editing window and call it as a notice.
Hence the PC/VB software provides the typing, editing and formatting options to the user.

2.2.3 RS 232:
RS 232 is a serial communication cable used in the system. Here, the RS 232 provides the serial communication between the microcontroller and the outside world such as display, PC or Mobile etc. So it is a media used to communicate between microcontroller and the PC.
In our project the RS232 serves the function to transfer the edited notice (or data) from PC (VB software) to the microcontroller, for the further operation of the system.

2.2.4 RS 232 to RS 485 Converter:
In this RS 232 to RS 485 converter block we are going to interface the RS 232 cable and the RS 485 cable. Also this block meets the features required for the conversion of data or the signals from the RS 232 suitable format to the RS 485 suitable format. Then this RS 485 suitable format of the data can be travelled up to desired distance using this RS 485 cable.

2.2.5 RS 485:
As we know that RS 232 cable provides the limited distance of communication between PC and microcontroller, so we are using this RS 485 cable. The RS 485 cable is capable to transfer data to the lo9nger distance.
Using this RS 485 cable we can increase the distance of communication between the microcontroller and the PC .Because in our system we should get the desired or required distance of interest in PC and the microcontroller or display.

2.2.6 Microcontroller 89s52:
In our project we are feeding the program to the microcontroller to collect the data or notice transferred from PC through RS 232 and RS 485 cables.
After collecting or receiving the data it will save the received data into its on-chip memory.
And then as given in the program the controller will send or display the notice on the alphanumeric display in the required fashion i.e. rolling fashion.

2.2.7 Display:
In our project we are using the alphanumeric display. As the name “Alphanumeric display” suggests it is a type of display .But the difference between a normal display and the alphanumeric display is that it can display Alphabets as well as Numbers on it. So we don’t need the extra programming required to display the alphabets like in normal (LED Display).
Also it is brighter than the normal LED display.



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