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Propeller Led Display

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BHARATI VIDYAPEETH’S COLLEGE OF ENGINEERING FOR WOMEN CERTIFICATE This is to certify that "PROPELLER LED DISPLAY" Submitted by NAWALE TEJASHREE L. (ROLL NO. 46) SHINDE SUPRIYA S. (ROLL NO. 52) TIWARI NEHA D. (ROLL NO. 47) Of T.E. (Electronics and Telecommunication Engineering) is a bonafide work carried out by her under the supervision of Prof. M. S. Kasar and it is approved as the partial fulfillment of Mini Project & Seminar as per the syllabus of the University of Pune. Prof. M. S. Kasar Prof. S. T. Khot Guide Head,
Transcript
Page 1: Propeller Led Display

BHARATI VIDYAPEETH’S

COLLEGE OF ENGINEERING FOR WOMEN

CERTIFICATE

This is to certify that

"PROPELLER LED DISPLAY"

Submitted by

NAWALE TEJASHREE L. (ROLL NO. 46)

SHINDE SUPRIYA S. (ROLL NO. 52)

TIWARI NEHA D. (ROLL NO. 47)

Of T.E. (Electronics and Telecommunication Engineering) is a bonafide work carried out by

her under the supervision of Prof. M. S. Kasar and it is approved as the partial fulfillment of

Mini Project & Seminar as per the syllabus of the University of Pune.

Prof. M. S. Kasar Prof. S. T. Khot

Guide Head,

Department of E&TC Department of E&TC

Place: Pune

Date:

Page 2: Propeller Led Display

A

PROJECT REPORT

ON

"PROPELLER LED DISPLAY"

PRESENTED BY

NAWALE TEJASHREE L.

SHINDE SUPRIYA S.

TIWARI NEHA

GUIDED BY

Prof. M. S. Kasar

DEPARTMENT OF ELECTRONICS AND TELECOMMUNICATION ENGINEERING

BHARATI VIDYAPEETH’S

COLLEGE OF ENGINEERING FOR WOMEN

PUNE 411043

APRIL 2011

Page 3: Propeller Led Display

ACKNOLEDGEMENT

First, we would like to express our best regards to our project guide Prof. M.S.Kasar,

whose valuable guidance, encouragement, and provision of necessary facilities made this work

possible.

We are also thankful to our respected Head of the Department Mrs. S.T.Khot 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.

Our special thanks to Mr. S.H. Deshmukh who helped us a lot through the problems we

came across. We are absolutely grateful to all non-teaching staff for their assistance which is key

factor behind our success. We would also like to express our gratitude towards the college for

providing us with the best facilities and proper environment to work on 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.

Project Team

Ms. Nawale Tejashree L.

Ms. Shinde Supriya S.

Ms. Tiwari Neha D.

Page 4: Propeller Led Display

CONTENTS

CHAPTER TITLE PAGE NO.

1 INTRODUCTION 1

2. SPECIFICATIONS 2

2.1 CIRCUIT SPECIFICATION 2

2.2 ELECTRICAL SPECIFICATION 2

2.3 MECHANICAL SPECIFICATION 2

3. LITERATURE SURVEY 3

4. BLOCK DIAGRAM 5

4.1 BLOCK DIAGRAM DESCRIPTION 6

5. MODULE WISE DESIGN 7

5.1 INTERRUPT MODULE 9

5.2 SPEED OF LEDS 10

5.3 MICROCONTROLLER REACTANCE

TIME

11

5.4 POWER SUPPLY 12

6. MECHANICAL ASSEMBLY 13

7. CIRCUIT DIAGRAM 14

7.1 WORKING 15

8. ALGORITHM 16

9. FLOWCHART 17

10. PROGRAM 18

11. PCB LAYOUT 25

11.1 PCB MAKING 26

11.2 STEPS FOR PCB DESIGNING 27

11.3 ASSEMBLY OF COMPONENTS ON PCB 27

12. TROUBLESHOOTING MANNUAL 27

13. BILL OF MATERIALS 28

Page 5: Propeller Led Display

14. ADVANTAGES 30

15. APPLICATIONS 30

16. RESULT AND CONCLUSION 31

17. FUTURE SCOPE 34

18. REFRENCES 35

Page 6: Propeller Led Display

INTRODUCTION

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 40-pin 8051 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 40 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.

Page 7: Propeller Led Display

SPECIFICATIONS

SPECIFICATION OF THE SYSTEM:

8-bit microcontroller AT89V51RD2 with flash program memory. Interrupt sensor MOC 7811. DC motor with 1975 RPM. +5V power supply using IC 7805.

SPECIFICATION:

MICROCONTROLLER AT89V51RD2: 64KB flash program memory. 1Kb of data RAM. 5V operating voltage from 0 to 40 MHZ. Four 8-bit I/O ports with three high-current port 1 pins (16Ma each). Support 12 clock or 6-clock mode selection via software or ISP.

INTERRUPT SENSOR (MOC 7811): Photo Gap Detector Output Circuit Type=Transistor Mounting hole diameter: 3mm Mounting hole spacing: 19mm Slot width: 3mm Slot depth: 7mm I (F) Max. (A) Forward Current=50mA I(O) Max.(A) Output Current=1.9mA

DC MOTOR: Tape recorder motor. Input voltage: + 12v. Current capability: 750mA RPM: 1975/min

ELECTRICAL SPECIFICATION : Fixed regulated power supply. Output voltage rating: +12V. Short circuit protection.

MECHANICAL SPECIFICATION:

Page 8: Propeller Led Display

PCB size: 8cm x 5cm

Enclosure size: 18cm x 10cm

LITERATURE SURVEY

Page 9: Propeller Led Display

The reference support that the circuit diagram and other related information taken from

website:

1. http://www.luberth.com/analog.htm

2. http://www.jogy.ch/files/Circuit_Cellar_Design_Contest_H3210/

Propeller_Display.pdf

3. http://www.8051projects.net/comment-n153.html

4. http://www.circuitlake.com/propeller-128-light-contoller.html

5. http://www.gadgetgangster.com/news/45-designer-news/290-led-matrix-displays-

with-the-prop.html

BLOCK DIAGRAM

Page 10: Propeller Led Display

Basic blocks of PROPELLER LED DISPLAY are:

1. Interrupter Module

2. Microcontroller

3. LED module

4. DC motor

5. DC power supply

Interrupter Module

Microcontroller

LEDDispl

ay

IRSenso

r

BeamInterru

ptIn eachrevoluti

on

DCmotor

DC Regulated

power supply

Page 11: Propeller Led Display

Interrupter module is our sensor module, consisting of the IR interrupt sensor MOC7811, from

Motorola Inc. This sensor was selected from a variety of other alternatives, because of its small

size, precise interrupt sensing, and sturdy casing.

One great advantage of using this module is, interfacing it with the microcontroller is

just a matter of two resistors and a general purpose transistor.

Microcontroller AT89V51RD2

This project is based around the microcontroller AT89V51RD2, which is a derivative of

8051 family, from Atmel Inc. This is a 40 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.

LED MODULE

LED module consisting of 8 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.

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.

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.

MODULEWISE DESIGN

Page 12: Propeller Led Display

INTERRUPT MODULE

This device has a compact construction where the emitting-light sources and the detectors are located face-to-face on the same optical axis. The operating wavelength is 950 nm. The detector consists of a phototransistor.

FEATURES

Compact construction No setting efforts Polycarbonate case protected against ambient light 2 case variations 3 different apertures

INTERRUPT SENSOR DIAGRAM

CIRCUIT DIAGRAM:

Page 13: Propeller Led Display

R1:

R1 is dimensioned that on the sender a current of about 15mA flows.

R1=5V – Vled / I led

=5V- 1.6V/ 15mA

= 227Ω

An available value is 220Ω.

R2:

By testing different values I discovered an optimal value of 1kΩ.

Rc, Rb:

Rb limits the base current of the transistors. Rc sets the output current which this circuit can

deliver. On the microcontroller the input resistance of a pin is very high, i take a value of 10kΩ.

Page 14: Propeller Led Display

Now we can calculate the collector current.

I C=5V/Rc

=5V/10k Ω

=500µ A

The gain of the transistor 2N3904 with a collector current of 500μA is about 300.

We can calculate the required base current now.

I B= I C/β

=500µA/200

=1.6µA

Basis resistor Rb:

Rb=5V/I B

=5V/1.6µA

=3.1 MΩ=310 kΩ

To bring the transistor to saturation for Rb we are selecting value of 310 kΩ.

SPEED OF LEDS (FRAME RATE)

The rotational speed of the LED's affects directly how many pictures can be displayed in

a second. This corresponds to the frame rate.

On a modern TV, the frame rate is 100Hz. The more frame rate, the less flickering of the

picture.

Because on the Propeller Display the picture is scanned mechanically, it is not easy to

achieve high frame rates. For me it isn't possible to mechanics that can rotate the LED's

100 times a second.

The propeller has to be very well balanced to keep vibrations as low as possible and keep

the speed of the rerating LED's as high as possible.

How fast are the LED's when a picture is displayed with a frame rate of 25Hz?

Here is the Calculation.

Page 15: Propeller Led Display

Acceptance:

f = 25Hz (Frame rate)

r = 20cm (Radius from centre of rotation to the LED's)

u=2 ⋅ r⋅π=2⋅0.2m 3.141=⋅ 1.256m

v= f ⋅u 3600=25⋅ ⋅1.256m 3600=113.040⋅ m/h

=113.04 Km/h.

Acceptance:

f = 25Hz (Frame rate)

r = 6 cm (Radius from centre of rotation to the LED's)

u=2⋅r ⋅π=2⋅0.06m 3.141=⋅ 0.3769m

v= f ⋅u 3600=25⋅ ⋅0.3769m 3600=33921m/h⋅

=33.921km/h

We see that already a slow frame rate of 25Hz generates very high speeds on the LED's. The

bigger the radius of the display, the bigger is the speed and more vibrations accure.

MICROCONTROLLER:

Required reaction time of the microcontroller

Depending of the rotational speed of the LED's and the resolution of the display the

Microcontroller has to be quick enough to switch the LED's on and off in an acceptable time.

Here is a calculation of the minimum, the microcontroller has to react.

Page 16: Propeller Led Display

Acceptance:

f = 25Hz (25 frames in a second)

r = 6cm => u = 0.3769m

ILED = 5mm (Vertical distance between the LED's)

In order that a nice clean picture is originated, the horizontal and vertical distance from pixel to

pixel or LED to LED should be the same.

We calculate the number of displayable pixels on the horizontal axis.

PixelCountHorizontal = u/lLED

=0.3769/0.005m

=75.3 ≈ 76

The most speed of the microcontroller is needed when a LED is toggled every time. This

Corresponds to a bit pattern of 101010101... When this bit pattern can be displayed, every

Other bit pattern/picture can be displayed without problems.

POWER SUPPLY:

Page 17: Propeller Led Display

5V Regulator

For the 5V supply i took a LM7805 fixed 5V regulator. Beside the regulator itself some

Capacitors at the input and output are required. The values of the capacitors are taken from the

datasheet.

Maximal output current is 1A.

Min Input for 7805 is

= Drop across IC 7805 + Required Output voltage

= 3 V+ 5V

= 8

So at Input of 7805 we required 8 V with margin.

So we are using +9V battery to supply power to the circuitry.

MECHANICAL ASSEMBLY

Page 18: Propeller Led Display

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.

CIRCUIT DIAGRAM

MOC7811

Circuit

5V 12V

GND

Page 19: Propeller Led Display

CIRCUIT DISCRIPTION:

The circuit diagram is mainly consisting of three parts and these are as follows:

Page 20: Propeller Led Display

1. Interrupt module2. LED module 3. Microcontroller

In our circuit diagram interrupt module is used for synchronization purpose, and it requires +5V

power supply. We use IC MOC 7811 as a position encoder as its sensing power is high as

compare to other IC's. And output of interrupt module is taken from collector of 2N3904

transistor and connected to pin INT0 of microcontroller. The transistor 2N3904 is NPN

complimentary type transistor to invert output of MOC7811 sensor.

Microcontroller is heart of our circuitry. The output of interrupt module circuit is given to

INT0 pin of port 3. Port 1 is used as output port. LED is connected from port 1.0 to port1.7. We

use a foldable metal strip to provide an external interrupt to microcontroller.

An interrupt module consists of IR LED and Photodiode mounted facing each other

enclosed in plastic body. When light emitted by the IR LED is blocked because of some

completely opaque object, logic level of the photo diode changes. As we provide power supply

to DC motor, it starts to rotate and when the strip passes through the sensor then it gives the 0V

at output. The output of sensor is +5V when there is no interrupt. According to an external

interrupt the microcontroller decides to ON and OFF of the LED's.

Page 21: Propeller Led Display

SOFTWARE DESIGN

ALGORITHM

1. Start.

2. Load proper value in IE register, so that the interrupts INT0 and T0 are enabled. (IE

= 83H)

3. Offer higher priority to the INT0 (External) interrupt. (IP = 01H)

4. Configure timer 1 as 16-bit timer, and timer 0 as 8-bit auto reload mode timer.

( TMOD = 12H)

5. INT0 should be configured as edge interrupt. (IT0 = 1)

6. Configure port 3 as input port. (P3 = 0FFH)

7. Measure period of one revolution with T0

8. Stop the timers

9. Move th1 and tl1 into convenient registers.

10. Divide this 16 bit value by our total number of segments

11. Subtract the answer from 256, and load the result in th0.

12. After each timer overflow interrupt, display next value from look up table.

13. Start the timers.

14. Return from interrupt. Go to step 7.

Page 22: Propeller Led Display

FLOW CHART

Measure period of one revolution with T0

Load the result in T1 with auto reload mode.

Divide by 120

After each timer overflow interrupt, display next value

from lookup table

START

Page 23: Propeller Led Display

CODE

; $include (reg51.inc)

; T0 interrupt

Org 000h

Ajmp main

Org 000BH

Acall interr

Mov p3, #0ffH

RETI

; EXT0 interrupt

Org 0003H

Acall interr1

RETI

Org 230h

Lookup:

DB

10000010b,01111100b,01111100b,01111100b,10000010b,11111110b,1011110b,000000

00b,11111100b,11111110b,10111100b,01110010b,01110100b,01101100b,10011100b

DB

01111010b,01111100b,01011100b,00101100b,01110010b,11100110b,11010110b,10110

110b,00000000b,11110110b,00001100b,01101100b,01101100b,01101100b,01110010b

DB

10000010b,01101100b,01101100b,01101100b,11110010b,00111100b,01111010b,01110

110b,01101110b,00011110b,11100000b,00001100b,01101100b,00001100b,11100000b

DB

10011110b, 01101100b, 01101100b, 01101100b, 10000010b

Page 24: Propeller Led Display

Org 285h

DB

10000000b,01101110b,01101110b,01101110b,10000000b,00000000b,01101100b,01101

100b,10001100b,11110010b,10000010b,01111100b,01111100b,01111100b,01111100b

DB

01111100b,00000000b,01111100b,01111100b,10000010b,00000000b,01101100b,01101100b,01111100b,01111100b,00000000b,01101110b,01101110b,01111110b,01111110b

DB

00000000b,01111100b,01101100b,01101100b,01100000b,00000000b,11101110b,11101

110b,11101110b,00000000b,11111110b,01111100b,00000000b,01111100b,11111110b

DB

11111010b,01111100b,00000010b,01111110b,11111110b,00000000b,11101110b,11010

110b,10111010b,01111100b,00000000b,11111100b,11111100b,11111100b,11111100b

DB

00000000b,01111110b,11001110b,01111110b,00000000b,00000000b,10011110b,11101

110b,11110010b,00000000b,00000000b,01111100b,01111100b,01111100b,00000000b

DB

00000000b,01101110b,01101110b,01101110b,10011110b,10000010b,01111100b,01110

100b,01111000b,10000000b,00000000b,01101110b,01100110b,01101010b,10011100b

DB

10011000b,01101100b,01101100b,01101100b,10110010b,01111110b,01111110b,00000

000b,01111110b,01111110b,00000000b,11111100b,11111100b,11111100b,00000000b

DB

00000110b,11111010b,11111100b,11111010b,00000110b,00000010b,11111100b,11110

010b,11111100b,00000010b,00111000b,11010110b,11101110b,11010110b,00111000b

DB

00111110b,11011110b,11100000b,11011110b,00111110b,01111000b,01110100b,01101

100b,01011100b,00111100b,11111111b,11111111b,11111111b,11111111b,11111111b,

Page 25: Propeller Led Display

; Main Function

Org 0100h

Main:

Mov ie, #83H

Mov ip, 01H

Mov tmod, #12H

Mov th0, #00h

Mov tl0, #00h

Setb it0

Mov p3, #0FFh

Acall ramc

Mov th1, #00h

Mov tl1, #00h

Setb tr0

Setb tr1

Here: ajmp here

Interr: T0 interrupt

Cjne r6, #0ffh, sk

Mov r6, #00h

Acall disp

Sjmp sk1

sk:

Mov r6, #0ffh

sk1:

Clr tf0

RET

Page 26: Propeller Led Display

; EXT0 interrupt

interr1:

Clr tr1

Clr tr0

Mov a, th1

Mov r1, a

Mov a, tl1

Mov r0, a

Mov r3, #00h

Mov r2, #160

Acall div16_16

Mov a, r2

Subb a, 0ffh

Mov th0, a

Mov tl0, a

Mov th1, #00h

Mov tl1, #00h

Setb tr1

Setb tr0

Mov r0, #23h

Mov r5, #00h

Mov r6, #00h

RET

ramc:

Mov dptr, #600h

Mov r7, #30

Mov r0, #40h

loop1:

Mov a, r7

Page 27: Propeller Led Display

Subb a, #01h

Movc a,@a+dptr

Mov @r0, aDec r0Djnz r7, loop1RET

disp:

Cjne r5, #5, continue Mov a,@r0 Cjne a, #'[', space Mov p1, #11111111b Sjmp cont Space: Mov p1, #11111110b Cont: Inc r0 Mov r5, #00h Ajmp neglect

continue: Mov a,@r0 ; moves ASCII from RAM to R0 Clr c Subb A, #30h Mov b, #05 ; ASCII to address conversion Mul AB Mov dptr, #230h Add a, r5 ; Memory offset Movc A,@A+DPTR Mov p1,a Inc r5

neglect: RET Org 600h

Msg: DB 'PROPELLER [DISPLAY [[[[[[[[[[[[[[[[[[[[',0

div16_16: CLR C ; Clear carry initially

Page 28: Propeller Led Display

MOV R4, #00h ; Clear R4 working variable initially

MOV R5, #00h ; Clear R5 working variable initially

MOV B, #00h ; Clear B since B will count the number of left-shifted

bits

div1:

INC B ; Increment counter for each left shift

MOV A, R2 ; Move the current divisor low byte into the accumulator

RLC A ; Shift low-byte left, rotate through carry to apply highest bit to

high-byte

MOV R2, A ;Save the updated divisor low-byte

MOV A, R3 ; Move the current divisor high byte into the accumulator

RLC A ; Shift high-byte left high, rotating in carry from low-byte

MOV R3, A ; Save the updated divisor high-byte

JNC div1 ; Repeat until carry flag is set from high-byte

div2: Shift right the divisor

MOV A, R3 ; Move high-byte of divisor into accumulator

RRC A ; Rotate high-byte of divisor right and into carry

MOV R3, A ; Save updated value of high-byte of divisor

MOV A, R2 ; Move low-byte of divisor into accumulator

RRC A ; Rotate low-byte of divisor right, with carry from high-byte

MOV R2, A ; Save updated value of low-byte of divisor

CLR C ; Clear carry, we don't need it anymore

MOV 07h, R1 ; Make a safe copy of the dividend high-byte

MOV 06h, R0 ; Make a safe copy of the dividend low-byte

MOV A, R0 ; Move low-byte of dividend into accumulator

SUBB A, R2 ; Dividend - shifted divisor = result bit (no factor, only 0 or 1)

MOV R0, A ; Save updated dividend

MOV A, R1 ; Move high-byte of dividend into accumulator

SUBB A, R3 ; Subtract high-byte of divisor (all together 16-bit subtraction)

MOV R1, A ; Save updated high-byte back in high-byte of divisor

Page 29: Propeller Led Display

JNC div3 ; if carry flag is NOT set, result is 1

MOV R1, 07h ; otherwise result is 0, saves copy of divisor to undo subtraction

MOV R0, 06h

div3:

CPL C ; Invert carry, so it can be directly copied into result

MOV A, R4

RLC A ; Shift carry flag into temporary result

MOV R4, A

MOV A, R5

RLC A

MOV R5, A

DJNZ B, div2 ; now count backwards and repeat until "B" is zero

MOV R3, 05h ; Move result to R3/R2

MOV R2, 04h ; Move result to R3/R2

RET

END

Page 30: Propeller Led Display

PCB LAYOUT

Page 31: Propeller Led Display

PCB LAYOUT/ART WORK DESIGN

PRINTED CIRCUIT BOARD

Much modern electronic system would be virtually impossible to package without incorporating

printed circuit board. A printed circuit board popularly known as PCB, is a piece of plastic

insulating board, on one side of which a complete layout diagram of an electronic circuit

consisting of copper as conductive layer is printed by a special photo generation process. On the

other side of PCB are mounted electronic components like capacitor, resister, inductor and IC's.

The metal conducting part serves as conducting medium for the electronic components that are

assembled on the opposite side of board.

PCB MAKING

Take proper scale of components and according to such scale make component lay out of project

circuit, on a paper. This layout is simple as well as small in size. Then draw mirror image of PCB

layout.

ARTWORK (PAINTING AND DRILLING)

Take copper clad board of required size and transfer mirror image layout on board. Drill for the

connection on proper track. Using the paints i.e. the mirror images drawn by mirror do the

painting. After some time check whether the paintings is in proper alignment with rack and if in

case there is any fault then correct it. Take solution of FeCI3 in port and dip PCB in solution for

some hours. After some time remove PCB from solution we see that the copper is removed from

copper clad board except that copper, which is painted.

STEPS FOR PCB DESIGNING

The following checklist uses the major area of concern in the process of PCB design:

a) Optimum size and shape of board should be ensured.

Page 32: Propeller Led Display

b) The substrate should be selected properly by taking into consideration its cost, mechanical

properties and electrical properties.

c) Layout of conductor pattern should be taken care from cross talk, leakage, shielding, numbers

of jumpers required and their placement.

d) Selection of conductor width, thickness and spacing should be done after analyzing their

placement.

e) Proper productive coating should be selected.

f) Thermal consideration should be analyzed properly.

g) Proper mounting of heavy and unstable component should be ensured.

h) Easy maintainability should be built in.

SIZE AND SHAPE

The size and shape of PCB is compromise among the many parameters. The maximum

size of board is determined by the available facility, like the wave soldering station, cleaning

lank, component assembling unit etc. When the board size is big and many components have

to be mounted on it, the probability of the failure of the board increases. Troubleshooting large

board increases. Smaller PCB's uses more connector; more back panel wiring, which can be

problematic due to bad contacts.

ASSEMBLY OF COMPONENTS ON THE PCB

Care has to be taken while soldering the component on the PCB. In a PCB the tracks are

quite closely spaced and probability of damaging them is more with inexperienced persons. This

demands him to have complete concentration. The risk of damaging the track is most while

soldering them off. Use of holder is certainly more advantageous for the soldering the ICs on the

PCB. This way we need not decoder the ICs to replace in case of failure.

Page 33: Propeller Led Display

TROUBLESHOOTING MANUAL

1. Output voltage of LM7805 is not 5V

Test the continuity throughout the wires, as shown in the circuit diagram. Replace appropriate component, if needed.

2. 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.

3. The display rotates, but not displaying garbage values.

Check the red strip (Interrupt) is in proper position or not. If not, adjust it.

4. 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.

Page 34: Propeller Led Display

BILL OF MATERIALS :

SR.NO COMPONENT NAME REFRENCE

NUMBER

QUANTITY RATE PER UNIT

AMOUNT

1. MICROCONTROLLER AT89V52RD2 1 55.00 55.00

2. REGULATOR IC LM7805 1 7.00 7.00

3. LED RED 8 1.00 8.00

4. DC MOTOR 2400 RPM 1 45.00 45.00

5. TAPE RECORDER FLYWHEEL

1 40.00 40.00

6. COPPERCLADE PCB 2 35.00 70.00

7. CAPACITOR 10µF,16V

33pF

2

2

1.50

1.50

3

3

8. CRYSTAL OSSCILLATOR

4.0952MHZ 1 7.00 7.00

9. IC BASE 40 PIN 1 1.00 1.00

10. SOLDERING WIRE 15METER 1 10.00 150.00

11. RELIMATE CONNECTOR

8 PIN

2 PIN

3

1

6.00

3.00

18.00

3.00

12. RESISTERS 10KΩ

1KΩ

220Ω

310KΩ

1

1

1

1

1.00

1.00

1.00

1.00

4.00

13. SENSOR IC MOC 7811 1 20.00 20.00

Page 35: Propeller Led Display

14. TRANSISTOR 2N3904 1 8.00 8.00

15. BATTERY +9V 1 38.00 38.00

16. ADAPTER +12V 1 45.00 45.00

17. ADAPTER SOCKET 3 PIN 1 15.00 15.00

TOTAL: 546/-

Page 36: Propeller Led Display

ADVANTAGES:

• It uses only 8 LED’s for display so hardware requirement is less.

• Maintenance and repairing is so easy.

• All the synchronizing can be implemented through software.

• Cost is very low.

• Because of its small size it take small space.

APPLICATION:

These displays are used at following places:

1. Large public Displays

2. Information Systems

3. For advertisement

4. Railway stations

5. Bus stands

6. In multiplex

Page 37: Propeller Led Display

RESULT AND CONCLUSION:

This project includes testing of three modules as stated below

1. Interrupter module testing

2. DC Motor RPM testing

3. Power supply module testing

INTERRUPTER MODULE TESTING

This Interrupter module testing is required for detecting exact position of wheel on which

whole circuit assembly is mounted.

Supply voltage given to Pin. No. 1(Collector) and Pin.No.3 (Anode) of MOC7811=5.5V

Output voltage obtained at Pin.No.1 of MOC 7811 without interrupt=5.21v

Output voltage obtained at Pin.No.1 of MOC7811 with interrupt=0.08V

Page 38: Propeller Led Display

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 = 12V.

Time interval between two successive pulses as seen on CRO = 30.4ms

RPS = 1 / (30.4ms)

=32.89

RPS = 33

RPM= 33x60

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

RPM = 1975 /min

Page 39: Propeller Led Display

FUTURE SCOPE:

• Propeller Clock.

• Message Flasher.

• Bike wheel LED display.

• Commercial product Children toy spinner.

Page 40: Propeller Led Display

REFRENCES:

The reference support that the circuit diagram and other related information taken from

website:

1. http://www.luberth.com/analog.htm

2.

http://www.jogy.ch/files/Circuit_Cellar_Design_Contest_H3210/Propeller_Display.pdf

3. http://www.8051projects.net/comment-n153.html

4. http://www.circuitlake.com/propeller-128-light-contoller.html

5. http://www.gadgetgangster.com/news/45-designer-news/290-led-matrix-displays-

with- the-prop.html

Various books have been referred for the designing of the circuit and to understand the

circuit in depth:

The books referred are:

1. MICROCONTROLLER THEORY AND APPLICATION

----- By M.A.MAZZIDI.

Second Edition, Pearson

Prentice Hall.

2. BASIC ELECTRONICS -----By B. Basavaraj &

H.S.Shivashankar, second

edition, Vikas Publication.


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