Propeller LED Display By Ketan kothari

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

InELECTRONICS AND COMMUNICATION

GOVERNMENT ENGINEERING COLLEGE, BHAVNAGAR

GUJARAT TECHNOLOGICAL UNIVERSITY,

CHANDKHEDA

December, 2014

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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.Dhaval N. Patel

Head of the Department

Prof. G.M.Chauhan



DEPARTMENT

CERTIFICATE

Date:__/__/__


LED DISPLAY” has been carried out by MAVANI PIYUSH B.




year 2013- 14.

Guide

Mr.Dhaval N. Patel

Head of the Department Prof. G.M.Chauhan

3



DEPARTMENT

CERTIFICATE

Date:__/__/__


LED DISPLAY” has been carried out by PANCHAL HARDIK C.




year 2013- 14.

Guide

Mr.Dhaval N. Patel

Head of the Department Prof. G.M.Chauhan

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)

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Abstract

This project is a special kind of circular LED display. With the

help some mechanical assembly, 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 Space Multiplexing. This

propeller display is mechanically scanned and displays the characters in

digital format. Made from 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.

List of FiguresFigure 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................................................18

Figure 6 Bottom View of module of propeller led display..........................................19

Figure 7 ATmega16 pin diagram.................................................................................26

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Table of ContentsAcknowledgement..........................................................................................................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???...................................................................14

1.6 Overview of Block Diagram..............................................................................14

1.6.1 Microcontroller Module..............................................................................14

1.6.2 LED Module................................................................................................14

1.6.3 DC Motor....................................................................................................15

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....................................................18

2.4 Bottom View of module of propeller led display...............................................19

Chapter 3 Software Design................................................................................20

3.1 Software Used Ride IDE....................................................................................20

3.2 Algorithm...........................................................................................................24

Chapter 4 PCB Design................................................................................25

4.1 PCB Designing Steps.........................................................................................25

4.2 ATmega 16 pin diagram.....................................................................................26

4.3 Pin Descriptions.................................................................................................26

Chapter 5 Results and Conclusions...................................................................29

5.2 DC Motor RPM Testing.....................................................................................30

5.3 POWER SUPPLY MODULE TESTING..........................................................30

Chapter 6 Appendix.......................................................................................30

6.1 User’s Guide.......................................................................................................30

6.2 Troubleshooting Manual....................................................................................31

Bibiliography................................................................................................................33

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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.

1.2 Functional Diagram

Figure 1 Function Diagram

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1.3 BLOCK DIAGRAM

Figure 2 Block Diagram of Propeller LED Display

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

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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 Microcontroller Module

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.

1.6.4 DC Power Supply

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.

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Chapter 2 Hardware Design

2.1 Mechanical Assembly

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 Power Supply Module

Figure 4 Circuit Diagram of Power Supply Module

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

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2.4 Bottom View of module of propeller led display

Figure 6 Bottom View of module of propeller led display

Chapter 3 Software Design

3.1 Software Used Ride 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 PORTDunsigned 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

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delay();

break;}

case 'E':{

led=0x7f ;delay();led=0x49 ;delay();led=0x49 ;delay();led=0x49 ;delay();led=0x41;delay();led=0;delay();// Gbreak;

}

case 'C':{

led=0x3E ;delay();led=0x41 ;delay();led=0x41 ;delay();led=0x41 ;delay();led=0x22;delay();led=0;delay();// Gbreak;

}

case ' ':{

led=0x00 ;delay();led=0x00 ;delay();led=0x00 ;delay();led=0x00 ;delay();led=0x00;delay();led=0;delay();// Gbreak;

}

case 'B':

{led=0x7f ;delay();led=0x49 ;delay();led=0x49 ;delay();led=0x49;delay();led=0x36;delay();led=0;delay();// G0x7F , 0x49 , 0x49 , 0x49 ,

0x36,0, // Bbreak;

}

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 ;

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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();// Gbreak;}

}

}

void main()

{ DDRB=255;DDRD=255;while(1)

{ 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.

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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.

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.

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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.

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

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to VCC through a low-pass filter.

AREF

AREF is the analog reference pin for the A/D Converter.

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 = 33x60RPM = 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

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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.

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

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– 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

– 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

Bibiliographywww.nex-robotics.com

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http://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

http://www.logicbrigade.com/

Propeller LED Display By Ketan kothari

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