Propeller LED Display By Ketan kothari

1
PROPELLER LED DISPLAY
A PROJECT REPORT
Submitted By
KOTHARI KETAN M. (100210111052)
MAVANI PIYUSH B. (100210111023)
PANCHAL MANISH C. (110213111001)
In fulfillment of the award of degree
of
BACHELORS OF ENGINEERING
In
ELECTRONICS AND COMMUNICATION
GOVERNMENT ENGINEERING COLLEGE, BHAVNAGAR
GUJARAT TECHNOLOGICAL UNIVERSITY,
CHANDKHEDA
December, 2014

GOVERNMENTENGINEERING COLLEGE,BHAVNAGAR
ELECTRONICS & COMMUNICATION ENGINEERING
DEPARTMENT
CERTIFICATE
Date:__/__/__
This is to certify that the dissertation entitled “PROPELLER
LED DISPLAY” has been carried out by KETAN M. KOTHARI
under my guidance in fulfillment of the degree of Bachelor of
Engineering in Electronics and Communication 7th
Semester of
Gujarat Technological University, Ahmedabad during the academic
year 2013- 14.
Guide
Mr.DhavalN. Patel
Head of the Department
Prof. G.M.Chauhan

3
DEPARTMENT
CERTIFICATE
Date:__/__/__
LED DISPLAY” has been carried out by MAVANI PIYUSH B.
Semester of
year 2013- 14.
Guide
Mr.DhavalN. Patel
Prof. G.M.Chauhan

DEPARTMENT
CERTIFICATE
Date:__/__/__
LED DISPLAY” has been carried out by PANCHAL HARDIK C.
Semester of
year 2013- 14.
Guide
Mr.DhavalN. Patel
Prof. G.M.Chauhan

5
Acknowledgement
First, we would like to express our best regards to our project guide
Mr.D.N.Patel, whose valuable guidance, encouragement, and provision of necessary
facilities made this work possible.
We are also thankful to our respected Head of the Department
Mr.R.A.Thakkar whose help and shared knowledge was the main support to
complete our project. Many thanks are owed to our classmates for their useful
discussion and timely suggestions. Their technical support and encouragement helped
us to finalize our project.
Finally we offer our great thanks and regards to our family for their support
which helped us through the difficulty and hardships of life to earn this achievement.
KOTHARI KETAN M. (100210111052)
MAVANI PIYUSH B. (100210111023)
PANCHAL MANISH C. (110213111001)

Abstract
This project is a special kind of circular LED display. With the
help some mechanicalassembly, LED count, hardware requirement, and
hence overall cost is cut to very affordable price. Also, maintenance and
repairing of the display is so easy, that anyone having a little electronics
knowledge, can take care of this. All the synchronizing can be
implemented through software.
First of its kind, made using the 20 pin dip AT mega 16 series
microcontroller, this project use the principle of SpaceMultiplexing. This
propeller display is mechanically scanned and displays the characters in
digitalformat. Madefrom scrap it can be used anywhere and everywhere
and the most amazing fact about this display is its crystal clear display.
This display consists of just 8 bright LEDs which are rotated to show the
display.
For building this project, requirement is just a small 20 pin
microcontroller, a position encoder, and LEDs. This display can show the
messages, which will require a whopping 525 LEDs. So hardware and
cost minimization is achieved.

7
List of Figures
Figure 1 Function Diagram..........................................................................................11
Figure 2 Block Diagram of Propeller LED Display ....................................................12
Figure 3 Flow chart......................................................................................................13
Figure 4 Circuit Diagram of Power Supply Module....................................................16
Figure 5 Top View of module of propeller led display ...............................................17
Figure 6 Bottom View of module of propeller led display..........................................18
Figure 7 ATmega16 pin diagram.................................................................................25

Table of Contents
Acknowledgement .........................................................................................................5
Abstract ..........................................................................................................................6
List of Figures ................................................................................................................7
Table of Contents...........................................................................................................8
Chapter 1 Introduction.................................................................................10
1.1 About the Project ...............................................................................................10
1.2 Functional Diagram............................................................................................11
1.3 BLOCK DIAGRAM..........................................................................................12
1.4Flowchart ............................................................................................................13
1.5. What Is Propeller LED Display???...................................................................13
1.6 Overview of Block Diagram..............................................................................14
1.6.1 Microcontroller Module..............................................................................14
1.6.2 LED Module ...............................................................................................14
1.6.3 DC Motor ....................................................................................................14
1.6.4 DC Power Supply .......................................................................................15
Chapter 2 Hardware Design.........................................................................16
2.1 Mechanical Assembly........................................................................................16
2.2 Power Supply Module........................................................................................16
2.3 Top View of module of propeller led display....................................................17
2.4 Bottom View of module of propeller led display ..............................................18
Chapter 3 Software Design................................................................................19
3.1 Software Used Ride IDE....................................................................................19
3.2 Algorithm...........................................................................................................23
Chapter 4 PCB Design................................................................................24
4.1 PCB Designing Steps.........................................................................................24

9
4.2 ATmega 16 pin diagram ....................................................................................25
4.3 Pin Descriptions .................................................................................................25
Chapter 5 Results and Conclusions ...................................................................29
5.2 DC Motor RPM Testing.....................................................................................29
5.3 POWER SUPPLY MODULE TESTING..........................................................29
Chapter 6 Appendix.......................................................................................30
6.1 User’s Guide ......................................................................................................30
6.2 Troubleshooting Manual....................................................................................30
Bibiliography ...............................................................................................................34

Chapter 1 Introduction
1.1 About the Project
This project was started with a simple principle which is frequently
encountered in our everyday life, which is Persistence of Vision. This phenomenon
makes one feel fast moving/changing objects to appear continuous. 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.
Existing systems do employ POV principle, but for displaying each pixel,
individual LED is used. This results in a huge number of LEDs even for small sized
displays. By using a propeller type display, LED count can be kept to a bare
minimum. Even 8 LEDs can perform a task of over 525 LEDs.
Applications:
Applications can find their way into cost effective solutions for large public
displays, information systems. It can directly replace Railway station information
displays, bus stands and many more places.

11
1.2 Functional Diagram
Figure 1 Function Diagram

1.3 BLOCK DIAGRAM
Figure 2 Block Diagram of Propeller LED Display

13
1.4Flowchart
Figure 3 Flow chart
1.5. What Is Propeller LED Display???
Propeller:
Propeller is a term associated with a circular rotating object. As this project needs to

rotate whole circuit assembly, there must be some prime mover attached to it. So,the
term ‘Propeller’.
LED display:
This project using bright light emitting diodes for displaying the characters and
symbols on its assembly.
That’s why this project is named as ‘PROPELLER LED DISPLAY’
1.6 Overview of Block Diagram
In this section we will emphasize on detailed overview of each of the block
shown in previous block diagram. In every description of the block respective
schematics and working is explained.
The propeller display consists of following blocks, as shown in the block
diagram.
 Microcontroller
 LED module
 DC motor
 DC power supply
1.6.1 MicrocontrollerModule
This project is based around the microcontroller ATmega 16, which is a
derivative of avr family, from Atmel Inc. This is a 20 pin IC packaged in DIP
package. This small sized IC is used, mainly because of its reduced weight. This
improves the performance of the display, because reduced weight gives advantage of
increased RPM.
1.6.2 LED Module
LED module consisting of 10 bright LED is fixed in another side of the arm of
our project. These LEDs are connected with each of the port pin of microcontroller,
with a series current limiting resistor of 470 ohm.
1.6.3 DC Motor
Repeated scanning of the display is must for continuous vision. This task is
achieved using circular rotation of the whole circuit assembly. So, we used a DC
motor as the prime mover.

15
1.6.4 DC PowerSupply
For microcontroller, as well as the DC motor, a regulated DC power supply is
required. We have to provide +5V to the microcontroller, while +12V to the motor.
1.7 POV (Persistence of Vision):
This is the phenomenon which is related to vision capability of human eye by which
an after- image is thought to persist for approximately 1/25th of a second.
So, if someone is observing the images at a rate of 25 images per second, then
they appear to be continuous. The best example of this property is the red circle we
observe when we rotate the firecracker or incense stick in circle.

Chapter 2 Hardware Design
2.1 MechanicalAssembly
Mechanical assembly plays a vital role in proper functioning of this
project. The display is scanned each time, by rotating the whole assembly in a circular
path. The basic idea we developed is on our own, by implementing and modifying
different ways to do this
Following diagram shows the most reliable way, that we finally selected.Here, one
major challenge was how to bring +5V supply to the spinning circuit. We tried the
same by adopting two-three different methods, but finally concluded on the method,
as shown in the figure.
As seen in the diagram, one supply connection (GND) is provided
Through the motor’s shaft. Other terminal (Vcc) is connected, by arranging a friction
disc-brush arrangement. The brush keeps its contact with the disc, so that current can
be supplied.
Most critical objective was to achieve pristine balance and overall good
mechanical strength. For weight adjustment, we have provided one long screw, and
weight can be attached or removed by adding / removing metallic bolts. If the
assembly is balanced perfect, then it can achieve stability, and rotate at high RPMs
too. This will improve the overall efficiency of this display.
2.2 PowerSupply Module
Figure 4 Circuit Diagram of Power Supply Module

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A fixed voltage power supply producing constant +5V consists of step down
transformer, a bridge rectifier, filter capacitors C1 and 3 terminal regulator IC
LM7805. A step down transformer is selected in such a way that it produces 9V at the
input of IC. This power supply is capable of supplying +5v and load current up to
500m A.
The capacitor C2 connected between output terminal and ground cancels out any
inductive effect due to long distribution leads. Input capacitor C1 is used to improve
transient response of the regulator IC, i.e. response of regulator to sudden changes in
load. It is also helpful in reducing the noise present in the output. Dropout voltage
(Vin-Vout) needs to be at least 2V under all operating conditions for proper operation
of regulator.
2.3 Top View of module of propeller led display
Figure 5 Top View of module of propeller led display

2.4 Bottom View of module of propeller led display
Figure 6 Bottom View of module of propeller led display

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Chapter 3 Software Design
3.1 Software UsedRide IDE
The Resonance At mega Development Kits are a complete solution for
creating software for the AT mega 16 family of microcontrollers. The Development
Kits comprise many different tools that allow projects ranging from simple to highly
complex to be developed with relative ease. You will find that with the Resonance
Development Kits you can rely on tools that have been tested by real users over a long
period of time.
Ride provides a familiarity to the tools that will provided a basis for using
more complex features. It is assumed that the user is familiar with Windows and has
at least some familiarity with the AT mega 16 microcontroller family and the C
programming language
#include <avr/io.h>
#include <util/delay.h>
#define F_CPU 11059200
#define led PORTD
unsigned int del=75;
void delay(void)
{
_delay_us(del);
_delay_us(del);
_delay_us(del);
_delay_us(del);
}
void display(char car)
{
switch(car)
{
case 'G':
{
led=0x3E ;
delay();
led=0x41 ;
delay();
led=0x49 ;
delay();
led=0x49 ;
delay();
led=0x7A;
delay();
led=0;
// G

delay();
break;
}
case 'E':
{
led=0x7f ;
delay();
led=0x49 ;
delay();
led=0x49 ;
delay();
led=0x49 ;
delay();
led=0x41;
delay();
led=0;
delay();// G
break;
}
case 'C':
{
led=0x3E ;
delay();
led=0x41 ;
delay();
led=0x41 ;
delay();
led=0x41 ;
delay();
led=0x22;
delay();
led=0;
delay();// G
break;
}
case ' ':
{
led=0x00 ;
delay();
led=0x00 ;
delay();
led=0x00 ;
delay();
led=0x00 ;
delay();
led=0x00;
delay();
led=0;
delay();// G
break;
}
case 'B':

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{
led=0x7f ;
delay();
led=0x49 ;
delay();
led=0x49 ;
delay();
led=0x49;
delay();
led=0x36;
delay();
led=0;
delay();// G0x7F , 0x49 , 0x49 , 0x49 ,
0x36,0, // B
break;
}
case 'H':
{
led=0x7f ;
delay();
led=0x08 ;
delay();
led=0x08 ;
delay();
led=0x08;
delay();
led=0x7f;
delay();
led=0;
delay();
break;
}
case 'A':
{
led=0x7e ;
delay();
led=0x09 ;
delay();
led=0x09 ;
delay();
led=0x09 ;
delay();
led=0x7e;
delay();
led=0;
delay();
break;
}
case 'V':
{
led=0x1f ;
delay();
led=0x20 ;
delay();
led=0x40 ;

delay();
led=0x20 ;
delay();
led=0x1f;
delay();
led=0;
delay();// G
}
break;
case 'N':
{
led=0x7f ;
delay();
led=0x02 ;
delay();
led=0x04 ;
delay();
led=0x08 ;
delay();
led=0x7f;
delay();
led=0;
delay();// G
}
break;
case 'R':
{
led=0x7f ;
delay();
led=0x09 ;
delay();
led=0x09 ;
delay();
led=0x19 ;
delay();
led=0x66;
delay();
led=0;
delay();// G
break;
}
}
}
void main()
{ DDRB=255;
DDRD=255;
while(1)

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{ PORTB=0b00000011;
display('G');
display('E');
display('C');
display(' ');
display('B');
display('H');
display('A');
display('V');
display('N');
display('A');
display('G');
display('A');
display('R');
}
}
3.2 Algorithm
Main routine:
Load proper value in memory.
Offer higher priority to the INT0 (External) interrupt. (IP = 01H)
Configure timer 1 as 16-bit timer, and timer 0 as 8-bit auto reload mode timer.
(TMOD = 12H)
INT0 should be configured as edge interrupt. (IT0 = 1)
Configure port 3 as input port. (P3 = 0FFH)
Move input string to the video RAM area. (Call ‘ramc’ function)
Start the timers.
Initiate an infinite loop.

Chapter 4 PCB Design
4.1 PCB Designing Steps
The most important requirement of this project was to build a PCB with
minimum weight and size. A Zero PCB is a drilled board. Drilling process removes a
lot of material from board, and the weight is reduced. Designing method is as follows.
 Decide proper places for components
 Actual Placement of components on Zero PCB
 Connecting Tracks with solid wires
 Testing for continuity and Debugging
Four PCBs are designed in this project. The main PCB, the LED module, and power
supply PCB. All PCBs are constructed on simple zero PCB, and interconnection of
components was done by single stranded wires.

25
4.2 ATmega 16 pin diagram
Figure 7 ATmega16 pin diagram
4.3 Pin Descriptions
VCC Digital supply voltage.
GND Ground.
Port A (PA7..PA0)
Port A serves as the analog inputs to the A/D Converter.
Port A also serves as an 8-bit bi-directional I/O port, if the A/D Converter is not used.
Port pins can provide internal pull-up resistors (selected for each bit). The Port A
output
buffers have symmetrical drive characteristics with both high sink and source
capability.

When pins PA0 to PA7 are used as inputs and are externally pulled low, they will
source
current if the internal pull-up resistors are activated. The Port A pins are tri-stated
when
a reset condition becomes active, even if the clock is not running.
Port B (PB7..PB0)
Port B is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for
each
bit). The Port B output buffers have symmetrical drive characteristics with both high
sink
and source capability. As inputs, Port B pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port B pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port B also serves the functions of various special features of the ATmega16 as listed
on page 56.
Port C (PC7..PC0)
Port C is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for
each
bit). The Port C output buffers have symmetrical drive characteristics with both high
sink
and source capability. As inputs, Port C pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port C pins are tri-stated when a reset
condition becomes active, even if the clock is not running. If the JTAG interface is
enabled, the pull-up resistors on pins PC5(TDI), PC3(TMS) and PC2(TCK) will be
activated
even if a reset occurs.
Port C also serves the functions of the JTAG interface and other special features of
the
ATmega16 as listed on page 59.

27
Port D (PD7..PD0)
Port D is an 8-bit bi-directional I/O port with internal pull-up resistors (selected for
each
bit). The Port D output buffers have symmetrical drive characteristics with both high
sink
and source capability. As inputs, Port D pins that are externally pulled low will source
current if the pull-up resistors are activated. The Port D pins are tri-stated when a reset
condition becomes active, even if the clock is not running.
Port D also serves the functions of various special features of the ATmega16 as listed
on page 61.
RESET
Reset Input. A low level on this pin for longer than the minimum pulse length will
generate
a reset, even if the clock is not running. The minimum pulse length is given in Table
15 on page 36. Shorter pulses are not guaranteed to generate a reset.
XTAL1
Input to the inverting Oscillator amplifier and input to the internal clock operating
circuit.
XTAL2
Output from the inverting Oscillator amplifier.
AVCC
AVCC is the supply voltage pin for Port A and the A/D Converter. It should be
externally
connected to VCC, even if the ADC is not used. If the ADC is used, it should be
connected

to VCC through a low-pass filter.
AREF
AREF is the analog reference pin for the A/D Converter.

29
Chapter 5 Results and Conclusions
This project includes testing of two modules as stated below
1. DC Motor RPM testing
2. Power supply module testing
5.2 DC Motor RPM Testing
DC Motor used in this project is 12 V dc motor which is tested by using digital
contact-less tachometer. Arrangement was made so that the sensing circuit gives high
to low pulse for each completion of revolution. By measuring the time difference
between two successive pulses RPS can be calculated which further provide RPM
value, as shown below:
Power supply given to DC Motor = 9V
Time interval between two successive pulses as seen on CRO = 30.4ms
 RPS = 1 / (30.4ms)
=32.89
 RPS = 33
 RPM = 33x60
RPM = 1975
5.3 POWER SUPPLY MODULE TESTING
Power supply module was designed to provide 5V DC power supply necessary
to drive both motor and circuit. AC input is given from 9V 750mA transformer.
Results are as follows.
Input voltage, Vs=9V AC
Output voltage observed , Vo = 4.92V DC

Chapter 6 Appendix
6.1 User’s Guide
Steps To Be Performed Before Startup:-
 Connect the power cord to the AC mains power supply of 230V.
 Check whether the output of IC LM7805 is 5V or not. The power supply is ok
if the output is 5V.
 Now, connect the voltmeter’s probes to the motor’s terminals. 5V is the
desired voltage there.
 See if the Red LED on the main PCB is glowing or not. Glowing LED
indicates that it is receiving proper input voltage and so, on the Vcc of the
microcontroller.
 Adjust the interrupt ( Red strip) so that it easily passes through the sensor.
 Check if the Pin 6 of the microcontroller receives LOW voltage when interrupt
occurs, and HIGH voltage, otherwise.
 Finally, ensure that the standing assembly does not have any discrepancies.
6.2 Troubleshooting Manual
 Output voltage of LM7805 is not 5V
 Test the continuity throughout the wires, as shown in the circuit diagram.
 Replace appropriate component, if needed.
 DC motor is not rotating
 Check the current flowing through the motor. If it reaches above 750mA, then
the motor is short, Replace it.
 In case of jamming, try to grease the bearing and shaft.
 The display rotates, but not displaying garbage values.
 Some or all LEDs not glowing.

31
 Check the relimate connector, that connects the LED module to the
microcontroller.
 Otherwise, check the continuity through each wire.
 If the connections are ok, then replace the particular LED.
At mega 16:
Features
• High-performance, Low-power Atmel® AVR® 8-bit Microcontroller
• Advanced RISC Architecture
– 131 Powerful Instructions – Most Single-clock Cycle Execution
– 32 × 8 General Purpose Working Registers
– Fully Static Operation
– Up to 16 MIPS Throughput at 16 MHz
– On-chip 2-cycle Multiplier
• High Endurance Non-volatile Memory segments
– 16 Kbytes of In-System Self-programmable Flash program memory
– 512 Bytes EEPROM
– 1 Kbyte Internal SRAM
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85°C/100 years at 25°C(1)
– Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
– Programming Lock for Software Security
• JTAG (IEEE std. 1149.1 Compliant) Interface

– Boundary-scan Capabilities According to the JTAG Standard
– Extensive On-chip Debug Support
– Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface
• Peripheral Features
– Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes
– One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture
Mode
– Real Time Counter with Separate Oscillator
– Four PWM Channels
– 8-channel, 10-bit ADC
8 Single-ended Channels
7 Differential Channels in TQFP Package Only
2 Differential Channels with Programmable Gain at 1x, 10x, or 200x
– Byte-oriented Two-wire Serial Interface
– Programmable Serial USART
– Master/Slave SPI Serial Interface
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
• Special Microcontroller Features
– Power-on Reset and Programmable Brown-out Detection
– Internal Calibrated RC Oscillator
– External and Internal Interrupt Sources
– Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby
and Extended Standby
• I/O and Packages
– 32 Programmable I/O Lines

33
– 40-pin PDIP, 44-lead TQFP, and 44-pad QFN/MLF
• Operating Voltages
– 2.7V - 5.5V for ATmega16L
– 4.5V - 5.5V for ATmega16
• Speed Grades
– 0 - 8 MHz for ATmega16L
– 0 - 16 MHz for ATmega16
• Power Consumption @ 1 MHz, 3V, and 25°C for ATmega16L
– Active: 1.1 mA
– Idle Mode: 0.35 mA
– Power-down Mode: < 1 μA

Bibiliography
www.nex-robotics.com
www.logicbrigade.com
www.robozone.com
1. Mitchell’s modular LED x-y (horizontally and vertically digitally scanned array
system) was cite in the 29th International Science and Engineering Exposition "book
of abstracts", page 97,
Published by the "Science Service", Washington D.C. May 1978.
2. Technical reference detailing the LED display array, RF interface and scanning
circuit was included as part of the 1978 29th ISEF exhibition in Anaheim, CA.
Coltheart M.
3."The persistence of vision." Philos Trans R Soc Lond B Biol Sci. 1980 Jul 8;
290(1038):57–69. PMID 6106242.
4. “The 8051 microcontroller and Embedded Systems” by M.A.Mazidi.
5. Propeller Display Rennes’s H8 Design Contest 2003 Entry H3210
6. An Analog & Digital propeller clock I made! By Luberth

Propeller LED Display By Ketan kothari

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