TOUCH SCREEN BASED CONTROL OF INDUSTRIAL DEVICES A Thesis Presented to

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Nov 25, 2013 (4 years and 1 month ago)

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1


TOUCH SCREEN BASED CONTROL OF
INDUSTRIAL DEVICES






A Thesis

Presented to

The Faculty of the General Engineering

San José State University



In Partial Fulfillment

Of the Requirements for the Degree

Master of Science








By


AMUKTHA AKKINEPALLY


(007525076)







2



SAN JOSÉ STATE UNIVERSITY

The Undersigned Thesis Committee Approves the Thesis Titled

“TOUCH SCREEN BASED CONTROL OF
INDUSTRIAL DEVICES


By

AMUKTHA AKKINEPALLY


APPROVED FOR THE DEPARTMENT OF
GENERAL
ENGINEERING



__________________________________________________________

Dr. Leonard Theysley, Department of General Engineering,


05.02.11


__________________________________________________________

Dr. Javid Dorosti, Department of General Engineering,


05.02.11


_
________________________________________________________

Prof. Hamedi Hagh, Department of General Engineering,


05.02.11




APPROVED FOR THE

UNIVERSITY


__________________________________________________________

Associate Dean Office of Graduate Studies and Research


05.02.11





3


INDEX


NAME OF THE CONTENT







PAGE NO.


1.

Abstract










4

2.

Introduction










5

3.

Introduction to literature review







5

4.

Components used in the project







6

5.

Software used
in the project








6

6.

Block description









7

A.

Regulated power supply








7


B.

Micro controller P

IC16F877A







8

C.

Touch screen sensor








9

D.

Motor Driver Circuit L293D







11

7.

How system works









12

8.

Real world applications








13

9.

Conclusion










13

10.

References










14


LIST OF FIGURES









PAGE NO.


i.

Touch screen appliance








5

ii.

Block diagram of the project








7

iii.

Power Supply internal diagram







7

iv.

Pin Diagram of Microcontroller







8

v.

Touch screen sensor









9

vi.

Touch screen internal operation







10

vii.

Schematic diagram of the project







11

viii.

Working of the IR LED








12

ix.

LCD Display










12




4





ABSTRACT


This project

is designed for c
omplete automation of
a
switchboard with the help of
a
touch
screen sensor and a graphical LCD.
It is developed for c
ontrol of
industrial devices and
it
provides

a user
-
fri
endly environment for operating

the devices effectively.

The touch screen user
interface makes the system unique.

A
Microcontroller is use
d
as main
control unit
of the project
.
The output of the
system

is the DC M
otor. Its speed and direction change

accordingly.

The
project

can be used for control of high and low voltage devices. The
system

operates at low
power and reduces the chances of
switching charges therefore making the system durable.





























5


1.

Introduction:


This project

is based on touch screen technology.
A touch screen is a user interface to operate
any output de
vice. Unlike other interfaces, it is very user friendly. The heart of
the
control
system is a M
icrocontroller (
PIC16F877A).
The output device of the system is a DC motor
whose direction and speed are being controlled using the touch screen interface.







A Touch Screen Appliance


(
Retrieved

from

www.sandboxworld.com
, 05.02.11
)


2.

Introduction to Literature Review
:



I have reviewed some of the articles like “
Internet
-
based remote
control of a DC motor
using an embedded Ethernet

microcontroller
” (Wong Hong, Kapila Vikram, 2005)

and

Programming and applying of the multiple product distribution system by using PIC
16F877A microcontroller

(
Ozcan Varul, Melih Inal, 2009)
, the goal of
the
systems
mentioned in above articles

is automation,
but the basic aim
of low

p
ower consumption
and low cost is not achievable. My

project is basically advantageous as it is cost
effective, consumes low power giving a long life to the appliance. This tr
adeoff of these
advantages was not found in other device
s
.



6


3.

Components Used in the Project
:

These are the components used in
our

project
.


1.

Regulated Power Supply
-
5v DC

2.

Touch Screen Sensor




3.

Touch Screen driver

4.

Liquid Crystal Display(LCD)

5.

LCD Driver

6.

Microcontroller
-

PIC16F877A

7.

DC Motor

8.

Motor Driver Circuit
-

LM293D


The articles mentioned these components in the other systems primarily the DC Motor and

the Microcontroller. They were mostly the microcontroller based automated systems.


4.

Software
used in the Project
:


1.

Keil µ
vision

Compiler

-

Platform

2.

Embedded C



language

The systems me
ntioned in the articles used

the same software tool

(Keil µ
vision
). The
program code is generally in Embedded C in this tool.

The articles gave a good idea of
debugg
ing the same program in different methods.

7



Fig 1
Block diagram of the project




4
.
Block Description
:


A.

Regulated Power Supply
:


Power supply

block shown in Fig 1

is the basic requirement of any electronic device. In
this system
shown in Fig 2
we are making use of a 5V DC supply. Generally the power
supply which we get is 230V AC. It is converted into 5V DC for microcontroller and 12V
DC for DC motor. As the system is a mobile unit we use a battery which can provide the
system with the sufficien
t power supply.
Initially the 230V AC is converted into
pulsating DC at the adapter. The voltage regulator (7805) regulates into different voltage
levels required such as 5V and 12V. Then the output voltage from regulator is given to
filter which converts
the pulsating DC into ripple free DC.





DC Output

AC Power

AC/DC
Adapter

Regulator
(7805)

Filter

Fig 2 Power supply block diagram

8


B.

Microcontroller
-

PIC16F877A
:



A microcontroller is single integrated IC which internally has the other
components like
microprocessor, input


output ports, timers, clock and memory. The microcontroller
which we are using in the system is an 8
-
bit µC with 8KB on chip flash memory.



Fig 3 PIN Diagram of PIC16F874A


(Retrieved from
www.microchip.com
, May 05, 2011)


Microcontrollers generally contain general purpose Input Output ports. These ports are
software configurable to either input or output states. Generally output states are used for
int
erfacing external devices like LED’s or Motors.



9




Features of
the
PIC16F877A include




T
wo Pulse Width Modulation
s

each of 10
-
bit



256 Bytes of on chip data memory



S
ink/source

current of 25mA per

Input
-
output port.



Self
-
Programming



Parallel Slave Port

C.

Touch

Screen Sensor:

Touch Screen sensor can be any of the Cathode Ray (CRT) Tube or Liquid Crystal
Technologies (LCD).

Touch screen sensors can be of different types such as:

1. Capacitive Touch Screen

2. Resistive Touch Screen

3. Complete Touch Screen

The
touch screen which is used in this system is a resistive four wire touch screen
sensor.

They provide with 75% clarity and are commonly available in the market.

Resistive touch screens
consist
of two flexible sheets coated with a resistive material and
sepa
rated by an

insulating material
.
The

moment a
contact is made to the surface of the
touch screen, the two sheets are pressed together

as shown in Fig 4
, registering the
specific resistance value
of the touch. Touch screen sensors are used in many
applicati
ons. Some touch screen sensors are used in pen digitizers for signature capture,
smart phones, or pers
onal digital assistants (PDAs)

.

Touch screen

(
Retrieved

from
http://freddywal.tripod.com
, May 05, 2011)

10






Advantages of 4 wire resistive touch screen:



It works well even if the surface is suffered or scraped damage unless glass is not been
hurt.



It could be operated in the environment with
-
10 to 70 degree for automobile.



Warranty is as longer as 1 year for normal operating with 5,000,000 touching times.



It provides high transparency (more than 78%).



It is easy to install into varied brands of monitor.



Fig 4 Touch Screen Internal Operation


D.

Motor Driver Circuit
-

L
293D:


This is a driver circuit used to interface DC motor with microcontroller. This is a
high voltage, high current
H
-
bridge

driver

cir
cuit. It can deliver 600mA current

with 1.2A peak
surge per channel. This circuit can be used for controllin
g two motors simultaneously in two
different directions, i.e., clockwise and anti
-
clockwise directions. In our system we are
controlling the speed as well as direction of the output DC motor. This makes our system use
L293D circuit.





11


6.

The Schematic Dia
gram:

FIG 5







12


7.

How the System Works
:




Initially input is given by making a touch on the touch screen interface and the touch
screen driver registers specific voltage level. This voltage is changed into a specific XY co
-
ordinate. This is the main
Input to the Microcontroller. The microcontroller is pre
-
programmed
for certain set of XY values for a specific output. In this system we have divided the touch screen
interface into four quadrants giving four different reactions at the output DC motor.


i.

S
peed Increase

ii.

Speed Decrease

iii.

Clockwise movement

iv.

Anticlockwise movement


This system also measures the speed of the motor using white IR

LED diodes and displays it on
LCD screen.

The two IR LED diodes are placed Emitter and detector. The emitter keeps on
emitting the Infra
-
red radiations.
Whenever there
is a disturbance in between the emitter and
detector there is an input sent and
µC is programmed to count it as half revolution o
f the wing.
Hence the motor speed is calculated in revolutions per minute (RPM). This is displayed on LCD
.



Working of IR LED

(Retrieved from
http://www.twyman.org.uk
, May 05, 2011)





LCD
Display


(Retrieved from
http://www.electro
-
tech
-
online.com
, May 05, 2011)

13


8.

Real word Applications

of this project include
:



a. H
igh resolution touch screen interfaces


b. Flexible operative and automated switch boards


c. Appliances with good endurance


d. Portable devices


9
.

Conclusion
:




Automation
is the main aim of the design and development of new
electronics. This
project is among them, giving
basic automation of the user interface. Touchscreen,
the emerging
technology has great

scope

for the development. Many user
-

preferred applications and new
gadgets can be developed using this technology
. My

project gives a good idea of the design and
devel
opment of the basic technology.
Much advancement

can be made using this basic design.




























14



REFERRENCES:


1.

Mazidi
,
M
.
A
li

(2006)
. The 8051 Microcontroller and Embedded Systems: Using Assembly
and C

[
Text
Book].
Prentice Hall

Inc.

2,626.


2.

Vaglica, J.J.

&

Gilmour, P.S.

(1990)
;

How to select a Microcontroller [
Electronic version]
.
Institute for Electri
cal and Electronic Engineers
, 27 (11), 106.

3
.

Wong Hong & Kapila Vikram
(2005).

Internet
-
based remote control of a DC motor using an
embedded Ethernet

microcontroller

[Electronic version].
American Society for Engineering
Education
,

15(3), 57
-
67.


4.

http://owl.english.purdue.edu/