This document certifies that Mr. Ranjan Kumar, a student at ARYA INSTITUTE OF ENGINEERING AND TECHNOLOGY, successfully completed his major project on a propeller LED display to fulfill the requirements of Rajasthan Technical University. The project was guided by Mr. Pushpendra Foujdar and Ms. Numa M. Thapliyal. It acknowledges the support received from the Head of Department, Mr. Deepak Sharma. The abstract describes that the propeller LED display uses only 8 LEDs rotated by a motor to display text through persistence of vision, making it a low-cost effective solution.

1. CERTIFICATE
This is to certify that the Mr. RANJAN KUMAR IVth year VIII Sem,
RTU Roll No.-14EAIEE079 student of ARYA INSTITUTE OF
ENGINEERING AND TECHNOLOGY, JAIPUR (Electrical
Engineering) have successfully completed their major project.
PROPELLER LED DISPLAY
In the partial fulfillment of requirement as prescribed by the
Rajasthan Technical University, Kota in the year 2017-2018. It has
found satisfactory and is approved for the submission.
Mr. PUSHPENDRAFOUJDAR Ms. NUMA M. THAPLIYAL
(SEMINAR INCHARGE) (SEMINAR GUIDE)
AssistantProfessor Assistant Professor
Dept. Of ElectricalEngineering Dept. Of ElectricalEngineering
Mr. DEEPAK SHARMA
(Head of Dept.)
Associate Professor
Dept. Of Electrical Engineering
DEPARTMENT OF ELECTRICAL ENGINEERING
ARYA INSTITUTE OF ENGINEERING & TECHNOLOGY
SP-40, RIICO INDUSTRIAL AREA, JAIPUR (RAJASTHAN) – 302028

2. ACKNOWLEDGEMENT
I would like to express our special thanks of gratitude to our (H.O.D) Associate
Professor Mr. Deepak Sharma, Department Of Electrical Engineering,
“ARYA INSTITUTE OF ENGINEERING AND TECHNOLOGY”
KUKAS, JAIPUR, who gave us an opportunity to do work on propeller LED
display as a major project that project is based on the technology
“PERSISTANCE OF VISION” USING LED’S, which helped us in
understanding the subject very well and also gave us an exposure to many new
concepts. It has given us a lot of confidence and this will help us in our future
projects. It also helped us to understand how a group work is being carried and
to work efficiently as a team member. Secondly we would also like to thank
our parents and friends who helped us a lot in finalizing this project within the
limited time frame.
Ranjan Kumar
ElectricalEngineering
14EAIEE079
B.Tech4th
Yr. VIII Sem

3. ABSTRACT
Propeller LED Display is a special kind of circular LED display. The cost of project is less
effective by means of some mechanical assembly, less LED count, and hardware. Also,
maintenance and repairing of the display is easy, that anyone having a little electronics
knowledge, can take care of this. All the synchronizing can be implemented via software.
This propeller display will be mechanically examined and shows the characters in advanced
arrangement and data to be shown can be either fed by assembly level program or by an
android application using Bluetooth. With the help of Bluetooth module HC05 we can
display any text via android application (Arduino Bluetooth Terminal). This propeller
comprises of only 8 red LEDs which are arranged on to demonstrate the display. For building
this project, necessity is only microcontroller, a position encoder, and LEDs. This display
can demonstrate the messages, which will require 8 LEDs. So equipment and cost
minimization is accomplished. This project is very unique and made using the 20-pin 8051
series microcontroller. The project work on the principle of “Persistence of vision”. The
propeller display is mechanically scanned and displays the characters in digital format. The
most imaging task about the propeller display is its crystal clear display. This display consists
of just 8 bright LEDs which is capable of showing display. This project was started with a
simple principle which is frequently encountered in our everyday life (Persistence of Vision).
The phenomenon makes one feel that fast moving/changing objects to appear continuous,
which it move on a single axis. A television is a common example, in which image is re-
scanned every 25 times, thereby appear continuous. Further, a glowing object if rotated in a
circle at fast speed, it shows a continuous circle. By modifying this basic idea, 8 LEDs can
be rotated in a circle, showing 8 concentric circles. But if these LEDs are switched at precise
intervals, a steady display pattern can be shown. The Propeller LED Display is an electronic
device which has a series of LEDs on board that rotate with the help of a motor to give an
illusion of any text. This requires a DC motor which rotates the PCB connected to it with
sufficient speed soas to create the illusion. The LEDs are connected to a microprocessor
PIC16C84 or 16F84 which is so programmed to switch ON and OFFthe LEDs in a sequence
and with a time delay to approximately match with the rotating speed of the motor. One of
the phases of the DC motor is directly fed back to the microprocessor to identify the position
of the motor at any instant.