spinning LED Display system

Abstract
This project is spinning LED Display system which displays message programmed in a Microcontroller. By using the interface of PC message which we have to display is programmed in the Microcontroller. The Microcontroller is programmed by using the Microcontroller Programmer. The code is written using Visual Basic 6.0 software. This circuit needs to be mounted on to the mechanical structure {rotating disk} where it displays the messages that are stored in Microcontroller as indicated in the codes. The disk is rotated using a two phase motor. The speed of the motor is kept constant for the effect of Persistence of Vision. The message can be changed as per user need by rewriting the Microcontroller’s in built memory. The complete display system circuit is battery-run which is provided externally, where as the motor requires 230vollts AC to function.

Introduction
We’ve all seen a train or a car whizzing past us in the night. If its close enough and we don’t move our heads rather quickly, we see that its lights appear as horizontal lines instead of moving dots. This is due to a characteristic of our eyes known as Persistence of Vision. A quickly moving light appears to be in many places at once. If it’s on continuously, we see a solid line. If it’s flashing, we see a line of dots. This phenomenon can be thought of as the brain having a limited “frame rate”. We only think we’re seeing fluid motion around us because the brain is so good at piecing bits of data into continuous images and stories.
This is the basic principle of our Project named as ‘Spinning LED Display’.
To accomplish this, we first have to design and build the hardware components. The hardware mostly consists of a spinning wood platform, a DC motor, LEDs, any other circuitry (including the microcontroller). We have decided to begin with the Construction of hardware because there would be no way to test the code without functioning hardware. The code itself uses a modified version of the 7x5 ASCII character set included in a prior lab to create a message across the spinning wood Platform. With precise timing of the angular velocity of the platform, an individual byte of data (containing either ON or OFF for each LED) can be sent at the appropriate time so that a visible message appears. Also included in the code is the ability for the user to decide the color of the message (red, blue, or green) and the characters included in the message by using an attached keypad.

Objective
The goal of our project is to design a prototype of an enlarged version of the Spinning LED display for displaying message. After studying various techniques like matrix led’s, rolling displays ,etc which are also techniques of displaying message at the cost, therefore we choose spinning led display, an emerging technology applied for displaying message.
The display consists of 7 LEDs only in a vertical row. By moving them fast enough back and forth over each other, message can be displayed which appears to be generated by a 7*n matrix of LEDs and not a single column of LEDs, where n is the no. of columns of the display matrix.

WORKING
The basic principle of Persistence of vision is used in our Project named as ‘Spinning LED Display’. The project is a rotating LED display message display system which displays messages Programmed in microcontroller IC 89S52 or Wireless communication (RF) using parallel port is the transfer of information over a distance without the use of electrical conductors or "wires". In RF there is user input for the system.
We display the message using 7 led’s .this is done by building 2 diff. parts first is mechanical part (use for rotating whole circuit.) and second is Electrical part (deals with microcontroller and other electronics). In this the different messages will scroll, with respective intervals or delay by the microcontroller itself which is already programmed by the user. The code is written in using Visual Basic software. This circuit needs to be mounted on the mechanical structure (rotating disc) where it displays the messages .The disc is rotating using DC motor with the speed of 1000rpm; the motor speed is kept constant. The message can be changed as per user needs by rewriting the microcontroller in built memory or through RF via sending wireless data through pc. The complete display system circuit is battery- run on 5v, Dc motor works on 12V and current of 5 ampere.
This unique way of displaying messages is a very eye catching, for it is use in many fields like advertising, toys etc…

Advantages
 Basically a single column of led is used rather than multiple column of led.
 More amounts of data are displayed consuming less installation space.
 Low power consumption
 Long life because of using led’s
 View of displaying message is 360 degree.
 Due to microcontroller IC 89S52, we get more memory.

Disadvantages
 Due to dc motor there is small amount of noise.
 We have to keep safe distance from the display at the time of rotating.

Applications
 It is used to display information at public places. (e.g. .Stock Market)
 The similar principle is been used with the LCD and used for the display purpose in public places at US and UK & has a large market in India

FUTURE EXPANSION

 By increasing the size and the number of LED’s we can get better and bigger display.
 By using AC motor instead of DC motor we can get smoother, clear and more continuous display.
 Along with wireless RF communication we can also use GSM and Bluetooth technology for transmitting data wirelessly.
 By using processor having larger memory we can increase the length of message displayed one after other and by increasing the diameter of rotation we can increase the number of characters displayed at a time.

BIBLIOGRAPHY
• Websites:
 youtube.com
 wikipedia.com
 electronicsforu.com
 howdostuffwork.com