SINGLE OR MULTI ELECTRONIC NOTICE BOARDS WITH OPERATING DISTANCE

1KM USING RS485 PROTOCOL

SINGLE OR MULTI ELECTRONIC NOTICE BOARDS WITH OPERATING DISTANCE

1KM USING RS485 PROTOCOL

Guided ByGuided By : Presented By: : Presented By: Mr. Mr.NagarjunSingh,NagarjunSingh,

Asst.professor ,Asst.professor ,

P.Riyazkhan P.Riyazkhan 09U81A044709U81A0447

G.V.N.R.Sairam G.V.N.R.Sairam 09U81A041509U81A0415

K.Siva Krishna K.Siva Krishna 09U81A042609U81A0426

Sk.PeerSaheb Sk.PeerSaheb 09U81A046009U81A0460

OBJECTIVE OF THE PROJECT :

• The objective of the project is to develop a microcontroller based display system.

• It consists of PC, transmitter and receiver section, microcontroller and the display unit at the receiver side.

• It uses RF technology and embedded system to develop this app.

Contents:

• Introduction

• Overview of the technologies used

• Block diagram

• Hardware Implementation of the Project

• Firmware Implementation of the project design

• Results and Discussions

Introduction:

• Notice boards play a vital role mostly in educational institutions…

• The user need to go to the board to write the messages so that the employees/students come to know the issues of the institutions/offices.

• But this process consumes a lot time to update the news on all the notice boards…

• So we use the multi electronic notice boards…

• Here we are using RS485 protocol…

Continue…

• But in MAX485 up to 1500m limit…

• In addition we connect up to 32 devices…

• For full duplex you must use 2 units (or full duplex chip).

• For full duplex communication you need 4 wires

• MAX485 is providing half duplex mode…

Continue…• The project aims at displaying the messages on the

LCD using RS-485 protocol…

• This project is a device that collects data from the transmitting section…

• System that continuously checks for the data &

displays the same data on the LCD…

Continue…

• The S/w & H/w implementation help the microcontroller to read the data received from the transmitter section and display the received data on the LCD…

• It has an application program to allow the microcontroller read the transmitted data through the receiver and perform the action specified by the user…

• At any time, the user can add or change the message according to his requirement…

Over View Of The Technologies Used:

• Embedded Systems:• The embedded software is also called “firm ware”...

• An embedded system can be defined as a computing device that does a specific focused job …

• We can use it for a variety of applications such as playing games, word processing, accounting, software development...

Continue…

• In contrast, the software in the embedded systems is always fixed listed below …

• Generally, they do not have secondary storage devices such as the CDROM or the floppy disk…

• Embedded systems are constrained for power…

• Embedded systems have to work against some deadlines…

• Embedded systems operate through a battery, the power consumption has to be very low…

Advantages of Embedded Systems:

• They allow the system hardware to be simplified so costs are reduced…

• They are usually in the form of small computerized parts in larger devices which serve a general purpose…

• The program instructions for embedded systems run with limited computer hardware resources, little memory and small or even non-existent keyboard or screen.

RS-485

• RS-485 is used for point-point & multi-point data transmission…..

• Max distance covered by using rs-485 is up to 1200m…

• It is used for defining standard electrical char…

• Multiple receivers may be connected to such a linear n/w..

• These char..,make this n/w useful in industries..

Block diagram:

HARDWARE IMPLEMENTATION:

• It discusses the design and working & design with the help of block diagram and circuit diagram and explanation of circuit diagram in detail…

• It explains the features, timer programming, serial communication, interrupts of AT89C51 microcontroller.

• Project Design includes hardware and firmware implementations…

• Hardware implementation deals in drawing the schematic on the plane paper according to the application, testing the schematic design

Power Supply:

•The input to the circuit is applied from the regulated

power supply. The a.c. input i.e., 230V from the mains

supply is step down by the transformer to 12V

MICROCONTROLLERS:

• Microcontroller is a programmable device• The fixed amount of on-chip ROM, RAM and number of

I/O ports in microcontrollers makes them ideal… • 8051 is an 8-bit processor, meaning that the CPU can

work on only 8 bits of data at a time…•

LCD Screen: •RS = 1 - Bits D0 - D7 are addresses of characters that should be displayed•RS = 0 - Bits D0 - D7 are commands which determine display mode

LCD Connection• Depending on how many lines are used for connection to the

microcontroller, there are 8-bit and 4-bit LCD modes. The appropriate mode is determined at the beginning of the process in a phase called “initialization…

• Once the power supply is turned on, LCD is automatically cleared. This process lasts for approximately 15mS. After that, display is ready to operate. The mode of operating is set by default. This means that:

• 1. Display is cleared • 2. Mode DL = 1 Communication through 8-bit interface , N = 0 Messages

are displayed in one line F = 0 Character font 5 x 8 dots • 3. Display/Cursor on/off D = 0 Display off ,U = 0 Cursor off ,B = 0 Cursor blink off • 4. Character entry ID = 1 Addresses on display are automatically incremented by 1 ,, S = 0 Display shift off

Firmware Implementation :

• This chapter briefly explains about the firmware implementation of the project…

• Software Tools Required:• Kiel µv3, Proload are the two software tools used to

program microcontroller…•

•Kiel compiler is software used where the machine language code is written and compiled. After compilation, the machine source code is converted into hex code which is to be dumped into the microcontroller

Proload • Proload is software which accepts only hex files… • converted into hex code, that hex code has to be

dumped into the microcontroller…

• Features:

• 20 and 40 pin socket on-board • Simple and Easy to use

• Works on 57600 speed

• Error checking and verification in-built..•

Programming Software

•Computer side software called 'Proload V4.1' is executed that accepts the Intel HEX format file generated from compiler to be sent to target microcontroller. It auto detects the hardware connected to the serial port. It also auto detects the chip inserted and bytes used.

RESULTS AND DISCUSSIONS:

• It can be concluded that the design implemented in the present work provide portability, flexibility and the data transmission is also done with low power consumption…