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REMOTE CONTROL USING INFRARED WITH MESSAGE RECORDING
GUY KANG SHEN
UNIVERSITI TEKNOLOGI MALAYSIA
2008
REMOTE CONTROL USING INFRARED WITH MESSAGE RECORDING
GUY KANG SHEN
This thesis is submitted as a partial fulfillment
For the Degree of Bachelor
In Electrical Engineering
Faculty of Electrical Engineering
Universiti Teknologi Malaysia
MAY, 2008
Specially dedicated to My beloved family, teachers and lecturers who have
Encouraged, guided and inspired me throughout my journey of education.
Acknowledgement
First and foremost, I would like to grab this opportunity to express my sincere
gratitude to my project supervisor, En. Yusri Bin Md. Yunos for the guidance,
motivation, inspiration, encouragement and advice throughout the duration of
completing this project. Without his never ending support and interest, I have no idea
to process my project. My sincere appreciation also extends to my entire course
mates who have provided assistance at various occasions. Not forgetting my fellow
friends, who shared a lot of technical knowledge with me, encourage me to seek for
more knowledge and providing me some troubleshooting tips. I would like to thank
the senior (SET) from for providing me with the relevant idea. Last but not least, to
my beloved family who has always been there to encourage, comfort and give their
fullest support when I most needed them.
ABSTRACT
The primary objective of this project is to design a remote control system
integrated with a sound record IC (ISD2560). This project not only can let user turn
on or off multiple devices such as television and HI-FI, it also can leave message to
somebody. The combination of sound record system, wireless communication and
also the concept of “all in one” are adapted to the design which helps to reduce the
number of remote control at home and make the life more interesting. The users
either can leave a message or control the desired devices by just using this system
only. There are two main parts in the system, which are hardware and software
development. The schematic design for the system and components testing in
standalone state are include in hardware development. While the software skill
developed include drive circuit connection establishment and improvements to
algorithm. Some assumptions are made in the prototype system and
recommendations or future improvements are suggested.
ABSTRAK
Objektif utama projek ini adalah merekabentuk satu sistem kawalan jauh
dengan satu IC rakaman suara (ISD2560). Projek ini bukan sahaja dapat mengawal
“hidup” atau “mati” beberapa alat perkakasan elektrik seperti televisyen and HI-FI,
ia juga dapat digunakan untuk merakam mesej kepada seseorang. Penggabungan
sistem rakaman suara, perhubungan tanpa wayar dan juga konsep “semua dalam
satu”, sistem ini didapati akan membantu menggurangkan bilangan komponen
kawalan jauh dalam setiap rumah dan menjadi hidup lebih menarik. Pengguna boleh
merakamkan mesej atau mengawal alat perkakasan elektrik tertentu dengan hanya
satu sistem sahaja. Terdapat dua bahagian penting dalam projek ini, ialah pembinaan
perkakasan dan penggunaan perisian. Pembinaan perkakasan termasuk mereka
skematik untuk sistem dan meguji komponen secara berasingan. Bagi pembangunan
perisian, pembinaan perhubungan litar dan menambahbaikan algoritma adalah
diperlukan. Beberapa andaian telah dibuat dalam sistem prototaip ini dan cadangan
pembaikan juga dikemukakan.
TABLE OF CONTENTS
CHAPTER TITLE PAGE
TITLE PAGE i
DECLARATION ii
DEDICATION vi
ACKNOWLEDGEMENT vii
ABSTRACT viii
ABSTRAK ix
TABLE OF CONTENT x
LIST OF TABLE xiii
LIST OF FIGURES xiv
LIST OF ABBREVIATIONS xvi
LIST OF APPENDICES xviii
PART ONE
THESIS CONTENT
1 INTODUCTION
1.1 Overview 1
1.2 Project Objectives 2
1.3 Problem Statement 2
1.4 Project Scopes 3
1.5 Methodology and Approach 4
2 LITERATURE REVIEW
2.1 Overview 7
2.2 Conventional Remote Control system 7
2.3 Microcontroller
2.3.1 PIC16F877A Microcontroller
2.3.1.1 PIC16F877A Memory
Block
2.3.1.2 I/O Ports
8
9
11
14
2.4 ISD2560
2.4.1 Features
2.4.2 Detailed Description
2.4.3 Pin Description
2.4.4 Operation Modes
2.4.5 Typical Application Circuit
18
19
20
20
27
28
2.5 Voltage Regulator
2.5.1 Fixed Positive Voltage Regulator
7805
29
29
2.6 Infrared 30
2.7 Bootloader 31
2.8 MPLAB 7.62 32
3 Hardware Development
3.1 Introduction 34
3.2 Description of Remote Control with Message
Recording
34
3.3 Input and Output of the System 36
3.4 Assumptions of the System 36
3.5 Sk40A 37
3.6 ISD2560 40
3.7 Flow Chart 41
3.8 Infrared Module 43
3.9 System Schematic and Path List 44
4 Software Development
4.1 Overview 48
4.2 Software Development Environment 48
4.3 Programming with MPLAB 7.62 49
4.4 Bootloader with Hyper Terminal 55
4.5 Source Code 60
5 Result and Discussion
5.1 Overview 61
5.2 Result 62
5.3 Discussion 63
5.4 Problem Encountered 64
6 Conclusion
6.1 Overview 65
6.2 Conclusion 67
REFERENCES 67
Appendices A- C 70-89
LIST OF TABLES
TABLE TITLE PAGE
2.1 PIC16F877A devices features 10
2.2 PIC16F877A memory Bank select bits 14
2.3 Positive voltage regulator 20
2.4 Pin name, number and its function 27
3.1 In/ Out different modules 36
3.2 Port list for remote control system 47
5.1 Result 62
LIST OF FIGURES
FIGURE TITTLE PAGE
1.1 Methodology and Approach 4
2.1 Block diagram of a single chip microcontroller 8
2.2 Block diagram of a center processing unit (CPU) 8
2.3 Block diagram of PIC16F877A 11
2.4 Program memory map and stack 13
2.5 Simplified input- output unit 14
2.6 Block diagram of RA3:RA0 pins 15
2.7 Block diagram of RB3:RB0 pins 16
2.8 Block diagram of RB7:RB4 pins 17
2.9 ISD2560 device block diagram 18
2.10 ISD2560 device pin outs 26
2.11 ISD2560 application schematic examples 28
2.12 Fixed linear voltage regulator 7805 30
2.13 Bootloader enabled PIC16F877A schematic 32
3.1 Basic system flow 35
3.2 System flow 35
3.3 SK40A 38
3.4 Schematic of SK40A 39
3.5 Recording process in flowchart 41
3.6 Playback process in flowchart 42
3.7 Infrared module 43
3.8 Processing circuit 45
3.9 ISD2560 connection 46
4.1(a) MPLAB 7.62 49
4.1(b) Project wizard 50
4.1(c) Device selection 50
4.1(d) Active tool suite 51
4.1(e) Project name and browse 51
4.1(f) File adding 52
4.1(g) Project parameter 52
4.1(h) Build the project 53
4.1(i) Build option 54
4.1(j) Linker option 54
4.2 Preparation for bootloader 55
4.3(a) New connection 56
4.3(b) Connect using COM1 56
4.3(c) COM1 properties 57
4.3(d) Bootloader properties 58
4.3(e) ASCII setup 58
4.3(f) Bootloader started 59
4.3(g) Bootloader ended 59
4.4 Source code 60
5.1 Flow of the system 63
LIST OF ABBREVIATIONS
Ω - Ohm
μ - micro
COM - Communication
CPU - Central processing unit
DC - Direct current
EEPROM - Electrical erasable programmable real – only memory
F - Farad
h - Hexadecimal
Hz - Hertz
IC - Integrated Development Environment
IR - Infrared
IrDA - Infrared Data Association
I/O - Input / Output
JDM - Jens Dyekjaer Madsen
LED - Light emitting diode
m - milli
MCU - Microcontroller unit
MSB - Most Significant bit
OEM - Object Exchange Model
OSC - Oscillate
PIC - Peripheral interface controller
PC - Personal computer
PWM - Pause width modulation
RAM - Random access memory
RC - Resistor and capacitor
RISC - Reduces instruction set computing
ROM - Read only memory
Rx - Receiver
s - Seconds
TTL - Transistor-transistor logic
TV - Television
Tx - Transmitter
UART - Universal Asynchronous Receiver Transmitter
USB - Universal Serial Bus
W - Watt
LIST OF APPENDICES
APPENDIX
NO.
TITLE PAGE
A ISD 2560 Voice Record/ Playback Device 70
B Device Operation 74
C Operation Mode 79
CHAPTER I
PROJECT OVERVIEW
1.1 Introduction
In the mid-1980s, many of the external system components such as
microprocessor, memory and other build in peripherals has been integrated into the
same chip, resulting integrated circuit called microcontroller, and widespread use of
the embedded systems became feasible. By the end of the 80s, embedded systems
were the norm rather than the exception for almost all electronics devices. Embedded
system is a system that has a microcomputer or microcontroller inside which can
reads the input , process them and gives the feedback according to the preprogram
condition. Embedded systems are designed to do some specific tasks and have
minimal requirements for memory and program length. Since microcontroller can
provide high usability, this all in one remote control system using infrared with
sound recording is designed to support in turning on and off multiple electrical
devices such as TV, radio, DVD player at home to provide better performance and
functionality compared to current conventional remote control system. Beside that, it
also integrated with a sound record chip which use for message recording.
1.2 Project Objective
The objective of this thesis is to implement and monitoring the controlling of
all electrical devices and also include sound recording. The comfort offered by this
all in one remote control will bring users to the most satisfaction in daily life and
thus provider better quality of life. With the least number of remote control, user can
control most of the devices at home. With the sound recording chip integrated
together, user also can easy to leave messages for their family members. The system
is able to provide greater mobility and many more advantages then the conventional
remote control system. By using it, users are not required to purchase other message
recording system in order to leave message to someone. Through this, people can
easy to control and leave message.
1.3 Problem Statement
Nowadays, every home has remote control, something not only one, but a lot.
This already brings trouble to the users. Beside that, if a battery of one remote
control is finished. Other electronic device also can’t be operating.
Beside that, we always realize that most of the people prefer stick a small
paper in front of fridge for leaving a message to somebody. However, they do not
know that the small paper something will miss or fall always. And this will cause lot
problems. So that, with my project “all in one remote control with integrate sound
record” can overcome all of this problem and became one of the device that replace
traditional remote control.
1.4 Project Scope
This system design has consists of two parts, the first part would be the
message recording chip and another is PIC microcontroller. Human voice will be
input to the system and will be recorded to the chip and the voice can be play back.
However, the microcontroller plays the important role in setting up the connection
and became the mastermind behind the whole operation. The microcontroller will
receive input and process input from user through the switches and sending output to
the LED through infrared. Generally, there are four main scopes of work in this
project which includes:
1. System features design
2. Hardware development and prototyping
3. Software development and testing
4. System integration and implementation
System features design includes the initial idea of enhancing the current
remote control and the features that can be added into it. Then, hardware
development comes into places where various components are identified and
purchased. Later on, all the components needed are connected according to the
schematic and circuit designed. The circuit will be tested according to the schematic
and circuit designed. The circuit will be tested on the connectivity and will be
troubleshoot accordingly if the system fails. Training will be given to the system to
test on its functions and modes. Further testing is required to make sure that the
system is reliable and provides high quality output.
1.5 Methodology and Approach
The thesis is organized into five phases to be achieving this project:
1. hardware setup
2. programming for PIC microcontroller and testing
3. infrared connection setup and testing
4. ISD 2560 connection and testing,
5. PIC microcontroller and ISD 2560 integration.
The initial stage of the project would be planning and study on the component
needed to set up the prototype for microcontroller based circuit and ISD 2560.
Programming scripts are produced to enable microcontroller to communication with
the DIL switch and produce the output. Infrared connection is established
independently before integration.
The Figure 1.1 show the methodology and approaches for the project:
Figure 1.1 Methodology and approach
The model of microcontroller that will be used in this project is PIC 16F877A.
There is two different way to program the PIC, which is to write the source codes in
assembly language (low level language) or C language (high level language).
Assembly language can highly optimize the performance and memory usage.
However in writing a program for a system, high level language is recommended
because it is easier to organize and offers platform independent. A compiler is need
to compile the high level language (*.c file) to assembly language and assembler is to
produce machine codes (*.hex file) from assembly language. In this project, a
MPLAB 7.62 which can function as an editor, compiler as well as assembler is used.
There are three different ways to burn the program into the PIC:
1. Universal Programmer (ALL-11);
2. Home Made Programmer (JDM Programmer);
3. Bootloader
A universal programmer can be used to burn the machine code in various
type of PIC microcontroller. JDM programmer is more portable and able to
maximize the usage of input and output pin. While for bootloader, the
microcontroller could be attached with the circuit board while loading the program to
test. In other words, bootloader requires no expensive programmer and avoid the
chip from being pulled out from the circuit board. This can further simplify the
process of program loading and reduce the risk of damaging the microcontroller chip.
We just need a serial cable, microcontroller with bootloader firmware and simple
circuitry. So bootloader is chosen for this project for simplicity and low cost.
CHAPTER II
LITERATURE REVIEW
2.1 Introduction
The review of some technical knowledge and additional information about
current available solution to conventional remote control system are necessary to
identify the major components and design the entire system. In this chapter, some of
important hardware devices and software skill which were used in the project are
discussed.
2.2 Conventional Remote Control System
The first TV remote control, called “Lazy Bones” was developed in 1950 by
Zenith Electronics Corporation (then knows as Zenith Radio Corporation). Lazy
Bones used a cable that ran from the TV set to the viewer. A motor in the TV set
operated the tuner through the remote control. Although customers liked having
remote control to their television, they complained that people tripped over the
unsightly cable that meandered across the living room floor. Then, in 1956, Robert
Adler invented the Wireless TV Remote Control. By the early 1980s, the industry
moved to infrared, or IR, remote technology. The IR remote works by using a low
frequency light beam, so low that the human eye can not see it, but which can be
detected by receiver in the TV. The light used in a standard remote control to carry
the commands from the user to the appliance is the near-infrared range frequency of
approximately 980 nanometers, the edge of visibility. Today, remote control is a
standard feature on the other consumer electronic products, including VCRs, cable
and satellite boxes, digital video disc player and home audio receivers. A simple
remote control basically has a few basic buttons such as button 0-9, channel up and
down, volume up and down, power on/off, enter and mute. They are usually powered
by small AAA or AA size batteries.
2.3 Microcontroller
A microcontroller is a single-chip device that contains memory for program
information and data. It has logic for programmed control reading inputs,
manipulating data and sending outputs. It is a programmable integrated circuit that
can be used to control the operation of the system. In other words, it has built-in
interfaces for input/output (I/O) as well as central processing unit (CPU).
Microcontroller differs from a microprocessor in many ways. Microprocessor
needs other component like memory, or components for receiving and sending data.
However, microcontroller which integrates a number of the components of a
microprocessor system onto a single microchip, i.e. the central processing unit (CPU)
core, memory for both read only memory (ROM) and random access memory (RAM)
and some parallel digital Input/Output.
Figure 2.1 Block Diagram of a single chip microcontroller
Figure 2.1 shows a generic block diagram of microcontroller unit (MCU).
Internally, it has three basic parts: the central processing unit, memory and registers.
They are connected by an internal bus. Externally, it has pins for power, input/output
(I/O), and some special signals. I/O pins are grouped into units called I/O ports.
Figure 2.2 Block Diagram of a Central Processing Unit (CPU)
The CPU controls the operation of the microcontroller. It executes program
instructions. Note that the COU has its own registers. The program counter is a
special register that tell the CPU where to get an instruction or data byte. The other
registers store specialized data or address information. The instruction decoder tells
the arithmetic and logic unit what to do with the data. The control sequencer
manages the transfer of instruction and the data bytes along the internal data bus. The
address register set the condition of the address bus. The external address bus selects
a specified location in memory. The data driver conditions data signals to be sent to
or from memory or I/O registers.
2.3.1 PIC16F877A Microcontroller
PIC is the family of Reduces Instruction Set Computer (RISC)
microcontrollers made by Microchip Technology. It is generally regarded that PIC
stands for Peripheral Interface Controller, although General Instruments’ original
acronym for the PIC was “Programmable Intelligent Computer”. F is the referred to
flash program memory. The PIC16F877A is chosen because of its economical and
low cost, available of the chip and its related software and developer. Table 2.1
shows some device features about PIC16F877A.
Table 2.1 PIC16F877A devices features
Some features of PIC16F877A are summarized as follows:
1. Single-cycle intrusions, except for program branches
2. Up to 8K words of Flash Program Memory, 368 bytes of Data
Memory (RAM) and 256 bytes of EEPROM Data Memory
3. Timer0: 8-bit timer/counter with 8-bit prescaler
4. Timer1: 8-bit timer/counter with prescaler, can be incremented during
sleep Mode Via external.
5. Timer2: 8-bit timer/counter with 8-bit period register, prescaler and
postscaler
6. Typically 100,000 erase/write cycle Enhanced Flash Program memory
7. Typically 1,000,000 erase/write cycle Data EEPROM memory
8. Support both assembly and high level language
9. Wide operating voltage range (2.0 volts to 5.5 volts)
10. Low power high speed Flash/EEPROM technology
11. Low power consumption
12. Commercial and Industrial temperature ranges
The block diagram of the PIC16F877A is shown in Figure 2.3
Figure 2.3 Block diagram of PIC16F877A
2.3.1.1 PIC16F877A Memory Block
From the block diagram above, PIC16F877A contains Data EEPROM and
FLASH Program Memory. The Data EEPROM and FLASH Program Memory are
readable and writeable during normal operation (over the full VDD range). There are
three memory blocks which are data memory, program memory as well as stack. The
program Memory and Data Memory have separate buses so that concurrent access
can occur.
Program memory has been realized in FLASH technology, which makes it
possible to program a microcontroller many times before it is installed into a device
and even after its installment if eventual changes in program or process parameters
should occur. PIC16F877A devices have a 13-bit program counter capable of
addressing an 8K words × 14 bit program memory space with an address range from
000h to 1FFFh. Addresses above the range will wraparound the beginning of
program memory. The Reset vector is at 000h and the interrupt vector is at 0004h.
PIC16F877A has a group of 8 memory locations of 13 bits width with special
function. This group memory is known as stack. It basic role is to keep the value of
return address after a jump from the main program to a subprogram. In order for a
program to know how to go back to the point where it started from, it has to return
the value of a program counter from a stack. When calls a subroutine counter is
being pushed onto a stack. When executing instructions such as RETURN, RETLW
or RETFIE, which were executed at the end of a subprogram, program counter was
taken from a stack so that program could continue where it was stopped before it was
interrupted. Besides, the parameter passing from main program to subprogram will
cause a temporary memory location build in the stack.
Figure 2.4 indicates the program memory map and stack of PIC16F877A and
how subroutine being executed.
Figure 2.4 Program memory map and stack
Data memories consist of data EEPROM and RAM memories. EEPROM
data memory consists of 256 bytes locations whose contents are not lost during
losing of power supply. EEPROM is accessed indirectly through EEADR and
EEDATA registers. An EEPROM memory usually serves for storing important
parameters. There is a strict procedure for waiting in EEPROM, which must be
followed in order to avoid accidental writing. RAM memory is partitioned into four
banks, which contains the General Purpose Register and the Special Function
Registers. Each bank extends up to 128 bytes.
The data memory is partitioned into multiple bank which contains the
General Purpose Registers and the Special Function Registers. Bits RP1 and RP0 are
the bank select bits. Each bank extends up to 7Fh (128 bytes). The lower locations of
the each bank are reserved for the Special Function Registers. Above the Special
Functional Registers are General Purpose Registers, implemented as static RAM. All
implemented banks contain Special Function Registers.
Table 2.2 PIC16F877A Memory bank select bits
2.3.2 I/O Ports
The Input/ Output are the means by which the microcontroller communicates
to the environment which is outside the microcontroller system. I/O tends to be
groped into bytes wide ports (8 bits). I/O direction is relative to the microcontroller.
There are several types of ports: input, output or bidirectional ports.
Figure 2.5 Simplified input-output unit
PIC16F877A has five ports with a total 33 input/output pins. Each pin is
individually configurable as an input or output. The data direction depends on the
setting of the register TRIS at each port. If at the appropriate place in TRIS register a
logical “1” is written, then that pin is defined as an input pin , and if is “0” it will
become an output pin. Every port has its own address such as Port A is at 05h, Port B
is addressed at 06h, Port C at 07h, followed by Port D at 06h and port E at 09h.
Port A is a six bit wide, bi-directional port. Reading the port A’s register
reads the status of the pins, whereas writing to it will write to the port latch. All write
operations are read-modify-write operations. Therefore, a write to a port implies that
the port pins are read; the value is modified and then written to the port data latch.
Pin RA4 is multiplexed with the Timer 0 module clock input to become the
RA4/TOCKI pin. The RA4/TOCKI pin is a Schmitt Trigger input and open-drain
output. all other Port A pins has TTL input levels and full CMOS output drivers.
Other Port A’s pins are multiplexed with analog inputs and the analog VREF input
for both the A/D converters and the comparators.
Figure 2.6 Block diagram of RA3:RA0 pins
Port B is an 8-bit wide, bidirectional port. Each pin on the Port B has a weak
internal pull-up function and is activated by clearing bit RBPU. However, it is
automatically turned off when the port pin is configured as an output. The pulls-ups
are disabled on the Power-on Reset. There pins of Port B are multiplexed with the In-
Circuit Debugger and Low-Voltage Programming function: RB3/PGM, RB6/PGC
and RB7/PGD.
Another four pins of port B, RB&:RB4 have interrupt-on-change features.
This feature occurs when their status changes from logical one into logical zero and
opposite. Only pins configured as input can cause this interrupt to occur ,the input
pins on RB7:RB4 are compared with the old value latched on the last read of port B.
The mismatch output of RB7:RB4 are OR’ed together to generate the RB Port
changes interrupt with flag bit RBIF. This interrupt option along with internal pull-up
resisters is recommended for wake-up on key depression operation.
Figure 2.7 Block diagram of RB3: RB0 pins
Figure 2.8 Block diagram of RB7:RB4 pins
Port C is an 8-bits wide and bidirectional port. Port C is multiplexed with
several peripheral functions. Port C pins have Schmitt Trigger input buffers. When
enabling peripheral functions, care should be taken in defining TRIS bits for each
Port C pin. Some peripherals override the TRIS bit to make a pin an output, while
other peripherals override the TRIS bit to make a pin an input. Since the TRIS bit
override is in effect while the peripheral is enabled, read-modify-write instructions
with TRISC as the destination should be avoided. RC6 is used for UART (Universal
Asynchronous Receive Transmitter) asynchronous transmit while RC7 for
asynchronous receive. There two pins are important in data transfer between the
RS232 port at PC and microcontroller chip.
Port D is another eight bits port with Schmitt trigger input buffers. Each pin is
individually configurable as an input or output. Port D can be configured as an eight
bits wide microprocessor port (Parallel slave Port). In this mode, the input buffers are
TTL.
Port E has three pins only, which are individually configurable as input or
outputs. These pins have Schmitt trigger input buffers. The Port E pins become the
TTL. Port E pins are multiplexed with analog inputs. When selected for analog input,
these pins will read as zero. TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. On a Power-on Reset, these pins are configured
as analog inputs.
2.4 ISD 2560
Information Storage Devices ISD2560 Chip Corder series provides high
quality, single chip record/playback solutions for 60 second messaging application.
The CMOS devices include an on–chip oscillator, microphone preamplifier,
automatic gain control, anti aliasing filter, smoothing filter, speaker amplifier, and
high density multilevel storage array. Recordings are stored in on-chip nonvolatile
memory cells, providing zero-power message storage. The unique, single chip
solution is made possible through ISD patented multilevel technology. Voice and
audio signal are stored into memory in their natural form, providing high quality,
solid-state voice reproduction.
Figure 2.9 ISD2560 device block diagram
2.4.1 Features
Some features of ISD2560 are:
1. Easy-to-use single chip voice record/playback
2. High-quality, natural voice/audio
3. Manual switch playback can be edge- or level-activated
4. Directly cascadable for longer durations
5. Automatic Power-Down (Push- Button mode)
• Standby current 1μA (typical)
6. Fully addressable to handle multiple messages
7. Zero- power messages storage
• Eliminates battery backup circuit
8. On-chip clock source
9. single +5 volt power supply
10. 100 years message retention (typical)
11. 100,000 record cycles (typical)
12. Programmer support for play-only application
2.4.2 Detailed Description
The chip will be further explained from the aspect of sound quality produced,
the duration of the speech recording, the memory storage provided and the
programming availability of the chip. ISD2560 offered at 8.0 kHz sampling
frequency, allowing the sound quality produced to be quite good. The speech
samples are stored directly into on-chip nonvolatile memory without the digitization
and compression associated with other solutions. Direct analog storage provides a
very true, natural sounding reproduction of voice, music, tones, and sound effects not
available with most solid-state digital solutions.
ISD2560 offer single-chip solution at 60seconds. Parts may also be cascaded
together for longer durations. One of the benefits of ISD’s Chip order technology is
the use of on-chip nonvolatile memory; provide zero-power message storage. The
message can be re-recorded typically 100,000 times. ISD2560 is ideal for playback-
only applications, where single or multiple messages are referenced through buttons
or switches. It also includes all the necessary for microcontroller-driven applications.
Once the desired message configuration was created, duplicates can easily be
generated via an ISD programmer, which is expensive ($250).
2.4.3 Pin Description
Table 2.3 briefly describes the function of each pin of ISD2560 series and
Figure 2.10 shows the device pin outs.
Table 2.3 ISD2560 Pin name, number and its function
Pin Name Pin Number Function
Ax/Mx
1-10/1-7
Address/Mode Inputs: The Address/Mode
inputs have two functions depending on the
level of the two Most Significant Bits (MSB) of
the address (A8 and A9). If either or both of the
MSBs are LOW, the inputs are all interpreted as
address bits and are used as the start address for
the current record and playback cycle. The
address pins are inputs only and do not output
internal address information as the operation
progresses. Address inputs are latched by the
falling edge of CE’. If both MSBs are HIGH,
the Address/Mode inputs are interpreted as
Mode bits according to the Operational Mode
table. There are six Operational Modes
(M0…M6) available as indicated in Table 2.2.
It is possible to use multiple Operational Modes
simultaneously. Operational Modes sampled are
each falling edge of CE’, and thus Operational
Modes and direct addressing are mutually
exclusive.
AUX IN
11
Auxiliary Input: The Auxiliary input is
multiplexed through to the output amplifier and
speaker output pins when CE’ is HIGH, P/R’ is
HIGH, and playback is currently not active or if
the device is in playback overflow. When
cascading multiple ISD2500 devices, the AUX
IN pin is used to connect a playback signal
from a following device to the previous output
speaker drives. For noise considerations, it is
suggested that the auxiliary input not be driven
when the storage array is active.
VSSA, VSSD
13, 12
Ground: The ISD2500 series of devices
utilizes separate analog and digital ground
busses. These pins should be connected
separately through a low-impedance path to
power supply ground.
SP+/SP-
14, 15
Speaker Outputs: All devices in the ISD2500
series include an on-chip differential speaker
driver, capable of driving 50mW into 16Ω from
AUX IN (12.2mW from memory). The speaker
outputs are held at VSSA levels during record
and power down. It is therefore not possible to
parallel speaker outputs of multiple ISD2500
devices or the outputs of other speaker drivers.
Connection of speaker outputs in parallel may
cause damage to the device. A single output
may be used alone (including a coupling
capacitor between the SP pin and the speaker).
These outputs may be used individually with
the output signal taken from either pin. Using
differential outputs results in a 4 to 1
improvement in output power. Note, never
ground or drive an unused speaker output.
VCCA,
VCCD
16, 28
Supply Voltage: To minimize noise, the analog
and digital circuits in the ISD2500 series
devices use separate power busses. These
voltage busses are brought out to separate pins
and should be tied together as close to the
supply as possible. In addition, these supplies
should be decoupled as close to the package as
possible.
MIC
17
Microphone: The microphone input transfers
its signal to the on-chip preamplifier. An on-
chip Automatic Gain Control (AGC) circuit
controls the gain of this preamplifier from -15
to 24dB. An external microphone should be AC
coupled to this pin via a series capacitor. The
capacitor value, together with the internal 10kΩ
resistance on this pin, determines the low-
frequency cutoff for the ISD2500 series
passband.
MIC REF
18
Microphone Reference: The MIC REF input is
the inverting input to the microphone
preamplifier. This provides a noise-canceling or
common-mode rejection input to the device
when connected to a differential microphone.
AGC
19
Automatic Gain Control: The AGC
dynamically adjusts the gain of the preamplifier
to compensate for the wide range of
microphone input levels. The AGC allows the
full range of whispers to loud sounds to be
recorded with minimal distortion. The “attack”
time is determined by the time constant of a
5kΩ internal resistance and an external
capacitor connected from the AGC pin to
VSSA analog ground. The “release” time is
determined by the time constant of an external
resistor and an external capacitor connected in
parallel between the AGC pin and VSSA
analog ground. Nominal values of 470kΩ and
4.7μF give satisfactory results in most cases
ANA IN
20
Analog Input: The analog input pin transfers
its signal to the chip for recording. For
microphone inputs, the ANA OUT pin should
be connected via an external capacitor to the
ANA IN pin. This capacitor value, together
with the 3.0kΩ input impedance of ANA IN, is
selected to give additional cutoff at the low-
frequency end of the voice passband. If the
desired input is derived from a source other
than a microphone, the signal can be fed,
capacitive coupled, into the ANA pin directly.
ANA OUT
21
Analog Output: This pin provides the
preamplifier output to the user. The voltage
gain of the preamplifier is determined by the
voltage level at the AGC pin.
OVF
22
Overflow: This signal pulses LOW at the end
of memory space, indicating the device has
been filled and the message has overflowed.
The OVF’ output then follows the CE’ input
until a PD pulse has reset the device. This pin
can be used to cascade several ISD2500 devices
together to increase record/playback durations.
CE’
23
Chip Enable: The CE’ pin is taken low to
enable all playback and record operations. The
address inputs and playback/record input (P/R’)
are latched by the falling edge of CE’. CE’ has
additional functionality in the M6 (Push
Button) Operational Mode described later.
PD
24
Power Down: When not recording or playing
back, the PD pin should be pulled HIGH to
place the part in a very low power mode. When
overflow (OVF’) pulses LOW for an overflow
condition, PD should be brought HIGH to reset
the address pointer back to the beginning of the
record/playback space. The PD pin has
additional functionality in the M6 (Push
Button) Operational Mode described later.
EOM’
25
End-Of-Message: A nonvolatile marker is
automatically inserted at the end of each
recorded message. It remains there until the
message recorded over. The EOM’ output
pulses LOW for a period of TEOM at the end
of each message. In addition, the ISD2500
series has an internal VCC detect circuit to
maintain message integrity should VCC fall
below 3.5V. In this case, EOM’ goes LOW and
the device is fixed in playback-only mode.
When the device is configured in Operational
Mode M6 (Push Button Mode), this pin
provides an active-HIGH RUN signal,
indicating the device is currently recording or
playing. This signal can conveniently drive an
LED for a visual indicator of a record or
playback operation in process.
XCLK
26
External Clock: The external clock input for
the ISD2500 devices has an internal pull-down
device. These devices are configured at the
factory with an internal sampling clock
frequency centered to approximately 1 percent
of specification. The frequency is then
maintained to a variation of approximately 2.25
percent over the entire commercial temperature
and operating voltage ranges. The internal clock
has approximately 5 percent tolerance over the
industrial temperature and voltage range. A
regulated power supply is recommended for
industrial temperature range parts. If the XCLK
is not used this input must be connected to
ground.
P/R’ 27 Playback/Record: The P/R’ input is latched by
the falling edge of the CE’ pin. A HIGH level
selects a playback cycle while a LOW level
selects a record cycle. For a record cycle, the
address inputs provide the starting address and
recording continues until PD or CE’ is pulled
HIGH or an overflow is detected (i.e. the chip is
full). When a record cycle is terminated by
pulling PD or CE’ HIGH, an End-of-Message
(EOM’) marker is stored at the current address
in memory. For a playback cycle, the address
inputs provide the starting address and the
device will play until an EOM’ marker is
encountered. The device can continue past an
EOM’ marker in an Operational Mode, or if
CE’ is held LOW in address mode.
Figure 2.10 ISD2560 device pin outs
2.4.4 Operation Modes
The ISD2560 is designed with several built-in operational modes that provide
maximum functionality with minimum external components. The operational modes
are accessed via the address pins. When the two most significant bits (MSB) A8 and
A9 are HIGH, the remaining address bits are interpreted as mode bits Table 2.4
summarizes 6 operational modes for ISD2500 series. The mode control is set with
respective to the address pin. The jointly compatible feature allows some modes to
be used simultaneously.
Table 2.4 Operational modes
Mode
Control
Function Typical Use Jointly Compatible
M0
Message cueing
Fast forward
through
messages
M4, M5, M6
M1
Delete EOM’
marker
Position EOM’
marker at
the end of the last
message
M3, M4, M5, M6
M2
Not applicable
Reserved
N/A
M3
Looping
Continuous
playback from
Address 0
M1, M5, M6
M4
Consecutive
addressing
Record/Play
multiple
M0, M1, M6
consecutive
messages
M5
CE’ level-activated
Allows message
pausing
M0, M1, M3, M4
M6
Push button control
Simplified device
interface
M0, M1, M3
2.4.5 Typical Application circuit
Figure 2.11 ISD2560 application schematic examples
Figure 2.12 indicates the typical ISD2500 series application design schematic.
The input to the chip is voice or audio to microphone and the output is speaker. The
chip enable is pulled up using a 100kΩ resistor (R4).
2.5 Voltage Regulator
A voltage regulator is an electrical regulator designed to automatically
maintain a constant voltage level. It may be use an electromechanical mechanism, or
passive or active electronic components. Depending on the design, it may be used to
regulate one or more AC or DC voltages. With the exception of shunt regulators, all
voltage regulators operate by comparing the actual output voltage is too low, the
regulation element is commanded to produce a higher voltage. For some regulators if
the output voltage is too high, the regulation element is commanded to produce a
lower voltage; however, many just stop sourcing current and depend on the current
draw of whatever it is driving to pull the voltage back down. In this way, the output
voltage is held roughly constant. The control loop must be carefully designed to
produce the desired tradeoff between stability and speed of response.
2.5.1 Fixed Positive Voltage Regulator 7805
7805 is an integrated three-terminal positive fixed linear voltage regulator. It
supports an input voltage of 10 volts to 35 volts and output voltage of 5 volts. It has a
current rating of 1 amp although lower current models are available. Its output
voltage is fixed at 5.0V. The 7805 also has a built-in current limiter as a safety
feature. 7805 is manufactured by many companies, including National
Semiconductors and Fairchild semiconductors. The 7805 will automatically reduce
output current if it gets too hot.
It belongs to a family of three-terminal positive fixed regulators with similar
specifications and differing fixed voltages from 8 to 15 volts. There are usually
packaged in TO220 chip carries, but smaller surface-mount and larger TO3 packages
are also available. The last two digits represent the voltage; for instance, the 7805 is a
5-volt regulator. The 7805 is one of the most common and well-know of the 78xx
series regulators, as its small component count and medium power regulated 5V
make it useful for powering TTL devices.
Figure 2.12 Fixed linear voltage regulator 7805
2.6 Infrared
Infrared (IR) radiation is electromagnetic radiation of a wavelength longer
then that of visible light, but shorter then that of radio wave. IR data transmission is
employed in short-range communication. Remote controls and IrDA devices use
infrared light-emitting diodes (LEDs) to emit infrared radiation which is focused by a
plastic lens into a narrow beam. The beam is modulated, i.e. switched on and off, to
encode the data. The receiver uses a silicon photodiode to convert the infrared
radiation to an electric current. It responds only to the rapidly pulsing signal created
by the transmitter, and filters out slowly changing infrared radiation from ambient
light. Infrared communication are useful for indoor use in areas of high population
density. IR does not penetrate walls and so does not interface with other devices in
adjoining rooms. Infrared is the most common way for remote controls to command
appliances.
2.7 Bootloader
The PIC16F877A microcontroller from Microchip features flash based
program memory. The flash program memory can be written by running code
allowing the devices to be reprogrammed in process without an expensive EEPROM.
The Design Devices bootloader enabled PIC16F877A microcontroller contains a
special program that resides in the upper 255 instructions of program memory. This
special program executes when the microcontroller is powered on or reset. The
program check the B5 input pin and if it high it begins to read a MPLAB hex file
program and writes it to user program memory. The hex file data is uploaded using
the microcontroller’s SSP serial interface with the help of a special DOS upload
program called loader.exe. if the B5 input pin is low the bootloader program transfers
execution to the current user program in flash memory. Loader.exe is a program used
to communication to a Design Devices bootloader enabled PC microcontroller. It is a
simple program that can be run in a DOS window under Windows.
Figure 2.13 Bootloader enabled PIC16F877A schematic
2.8 MPLAB 7.62
MPLAB 7.62 is software program that runs on a computer to develop
applications for Microchip microcontroller. MPLAB 7.62 runs on a PC and contains
all the components needed to design and deploy embedded systems applications.
MPLAD 7.62 help to compile, assemble and link the software using the
assembler or compiler and linker to convert the code into “ones and zeros”, which is
machine code for the PIC micro MCUs. Its programmer’s Editor helps write correct
code with the language tools of choice. The Editor is aware of the assembler and
compiler programming constructs and automatically “color-key” the source code to
help ensure it is syntactically correct. The Project Manager enables to organize the
various files and library files. When building the code, you can control how
rigorously code will be optimized for size or speed by the compiler and where
individual variables and program data will be programmed into the device. If the
language tools run into errors when building the application, the offending line is
shown and can be “double-clicked” to go to the corresponding source file for
immediate editing. After editing, press the “build” button to try again. Often this
write-compile-fix loop is done many times for complex code.
The MPLAD also involves in testing the code. Usually a complex program
does not work exactly the way we imagined, and bugs need to be removed from the
design to get proper results. MPLAB 7.62 has components called “debuggers” and
free software simulators for all PIC microcontroller MCUs to help test the code.
CHAPTER III
Hardware Development
3.1 Introduction
This chapter will discuss about the development of the remote control system
using microcontroller and its interfacing circuit, ISD2560 and infrared module. The
hardware development generally involves the circuit design the whole system,
modular testing and how three different main modules were interconnected. This
chapter also provides the description of the project in detail based on the features of
this system.
3.2 Description of Remote Control with Message Recording
Before the implementation of the system, it is essential to model the system
flow in simple block diagram. There are two major part in this project, as illustrated
in Figure 3.1
Infrared Device 1
Device 2
PIC 16F877A microcontroller Switch
ISD2560 Record and Playback
Figure 3.1 Basic system flows
This system is divided into 2 paths; there are ISD2560 sound recording and
remote control. When we are operating the ISD2560 sound record chip, it can use to
record and playback. The period for recording maximum is 60 second. However, at
the same time we can’t use the infrared until the sound chip is disabled. After the
sound chip switch off, the all in one remote control will functional. These remote
control dints like the normal remote control but it can control the electrical devices
depend on the program we write inside the microcontroller.
Stage 1
ISD2560 switch ON
Speaker-Playback
ISD 2560
PIC Microcontroller
Idle Mic- Record
Stage 2
ISD2560 switch OFF
Infrared
Infrared
PIC microcontroller
Device 1
ISD2560 Idle Device 2
Figure 3.2 System flow
3.3 Input and Output of the system
Referring to the Figure 3.2 above, there are different input and outputs for
each module from end to end. Table 3.1 show the signal that a module receives an
generates.
Table 3.1 In-Out different Modules
PIC16F877A ISD2560 Device 1/2
Input Switch 1/2/3 Audio/Voice Infrared signal
output Infrared
signal/microcontroller
signal
SP+ and SP_ LED
When a user switch on switch 1, a signal will send to the microcontroller for
run the ISD2560 sound recording while the remote control work like idle. The
PIC16F877A microcontroller acts as a central processing unit to receive the
incoming microcontroller signal. When the switch 1 OFF, switch 2 and 3 will be
used for control the electrical devices.
3.4 Assumptions of the System
The project is proposed and designed to implement the idea of remote control
integrated with sound recording. Therefore, in order to prototype the system, several
assumptions are made.
• The status of LED shows the power state of device (ON or OFF).
• Switch is used to replace the keypad of remote control.
3.5 SK40A
In this project, the SK40A which is a PIIC microcontroller start up kit
developed by CYTRON Enterprises was used, SK40A which comes with bootloader
capability helps to ease the process of loading program and the further save
development time and cost. However, a few pins have been used for bootloader
function. Pins that involved were:
• MCLR (pin1),used as reset and connected to ‘Reset’ button.
• RB0 (pin 33), used as ‘Boot’ button and is pulled up through a
4.7kΩ resistor to 5V
• RC (pin 26), used as RxD and connected to MAX232
• RC6 (pin 25), used as TxD and connected to MAX232
• RD2 (pin 21), used as RTS and connected to MAX232
• RD3 (pin 22), used as CTS and connected to MAX232
The Reset and Boot button created can be used in development purpose.
Besides that, SK40A has onboard voltage regulator, 7805 which will provide stable
5V output to the PIC16F877A and other application from its wide range of input
voltages (7V-30V). therefore, user may extend the 5V from SK40A kit for external
use, no extra voltages is necessary. However, to overcome the problem of using
battery, adapter which can provide 5V, 0.5A was used. Once power is provided,
Power ON LED will light up. The features of the Sk40A do help to ready the
microcontroller. Once the program is ready and a hex file is generated, power is
provided to start-up kit, a serial cable is used to connect the SK40A to the serial
communication port at computer to enable the program uploading. Figure 3.3 show
the SK40A and some important indications on board and figure 3.4 shows the
schematic of Sk40A.
Figure 3.3 SK40A
Figure 3.4 Schematic of SK40A
3.6 ISD2560
The microphone inputs (pins 17 and 18) are connected differentially via
22mF capacitor to a microphone for low noise operation. Audio output comes
directly from the ISD2560 via speaker pins 14 and 15. Additional circuitry composed
of 220Ω resistor turns on the recording indicator LED when pins27 (P/R’) are low.
Pin 27 (P/R’) is connected to a toggle switch which will determine whether the
ISD2560 is in record mode or playback mode. There are 10 address lines on the
ISD2560. these can be hardwired to the correct modes of operations. However, the
two Most Significant Bits are HIGH (A8 and A9) so that the other 8 address lines are
interpreted as Mode bits according to the Operational Modes. There is 480k of
memory on the chip and this can be accessed non-sequentially by using the address
lines. There are address from 00 to 257 hexadecimal. The messages can also be
played sequentially or one message can be played in a loop depending on what mode
the chip is in. As mentioned, some of the modes can be used simultaneously to
provide better solutions.
The circuitries on the other pins of the ISD2560 are connected so that the IC
will function as the steps below in push button modes:
• Bring PD high, then low to stop the current cycle and reset the devices.
• Set P/R’ high to play, low to record.
• CE’ pin (high-low-high) to start the cycle.
• Bring PD high to stop record cycle and reset the device.
3.7 Flow Chart
The flow chart describes the system flow of recording and playback process.
START
STOP/RESET (PD) = low
LED Green = ON
Activate recording process (P/R’= low) LED Yellow = OFF
Press START/PAUSE (CE’) button to start
LED Red = ON
Recording starts User talks to the
microphone (>60s)
END
Figure 3.5 Recording process in flowchart
In this recording process (Figure 3.5), the PD pin (Stop/Reset) first has to be
low using a mini slide switch. LED green will light on. Also, the P/R’
(Playback/Record) pin is taken low to activate the record mode and at the same time
LED yellow will light on. Now, the system is ready for doing recording. We have to
press the CE’ pin (Start/Pause) button when speak to the microphone and release it
when stopping. The voice input will be saved in the memory inside the chip. The
maximum duration of the recording is 60 seconds. The chip will always monitor the
timing and user is expected not to recording a message more then 60 second length.
If the chip overflows, the chip will end the recording immediately.
STARTSTART
STOP/RESET (PD) = low
LED Green = ON
Activate recording
process (P/R’= high) LED Yellow = ON
Press once time START/PAUSE (CE’)
button to start playback LED Red = ON
Starting playback
END
Figure 3.6 Playback process in flowchart
Figure 3.6 shows the flow of playback process. The PD pin (Stop/Reset) is
set to low and P/R’ pin (Playback/Record) is taken high to activate playback mode.
When the CE’ (Start/Pause) is pulsed low one time, the playback starting play. The
maximum duration of playback period exceeds 60 seconds. However when we
pulsed high pin (Stop/Reset), all the progress will stop and reset.
3.8 Infrared Module
A simple infrared module was developed to represent the current infrared
remote control. The infrared transmitter was powered with +5V, so that it can always
generate signal. The same goes to the receiver to be able to detect the signal. The
simple infrared is developed as illustrated in figure 3.6 below.
Figure 3.7 Infrared module
3.9 System Schematic and Path List
In this project, both wired and wireless communication techniques are applied
to implement this all in one remote control system. The processing circuit as
illustrated in figure 3.7 and figure 3.8 is the main circuit design of the system. This
part of the system comprises most of the components compared to the infrared
module which is only a modeling circuit to represent devices. The components used
in the processing circuit are as listed below:
• SK40A, used as central processing unit
• ISD2560 used as the sound record
• Infrared transmitter
• Some common components such as resistors, capacitor, switches, etc.
Figure 3.7 show the schematic of the processing circuit while the figure 3.8
illustrates ISD2560 sound record path. The system is presented in two schematic
diagrams because of it complexity.
Figure 3.8 Processing circuit
Figure 3.9 ISD2560 connection
Table 3.2 summarizes the part list of two schematic diagrams above. Two
sets of infrared module are used to represent two devices to implement multiple
devices controlling.
Table 3.2 Part list for the remote control system
Item Value Description Amount
SK40A Microcontroller start up kit 1
PIC16F877A Microcontroller 1
ISD2560 Sound record IC 1
Infrared Tx 1x2
Infrared Rx 1x2
LEDs 1x5
Mini slide switch 1x4
Resistor(Ω) 10K 1x2
470K 1
1K 1
100K 1
5.1K 1
220 1x7
Capacitor(F) 220u 1
0.1u 1x5
22u 1
4.7u 1
CHAPTER IV
SOFTWARE DEVELOPMENT
4.1 Overview
The software skills are important is this project in order to develop a fully
functional remote control system. In this chapter, the discussions are mainly about
the environment for programming, load the program into microcontroller and
modifications to simplify the program flow.
4.2 Software Development Environment
Two software programs are used in this project, which are MPLAB 7.62 as
compiler to the program, and Hyper Terminal for bootloader.
4.3 Programming with MPLAB 7.62
An additional language tool is selected to support this project together with
MPLAB 7.62 to create the software environment for programming, which is HI-
TEACH. It is a C compiler, Assembler and Linker. The following figures will show
how to create a project environment in MPLAB 7.62 with HI-TEACH PICC tool
suite.
Figure 4.1(a) MPLAB 7.62
Figure 4.1(a) shows the start up window for MPLAB 7.62 program. A new
project is set up using Project Wizard as illustrated in Figure 4.1(b).
Figure 4.1(b) Project Wizard
After the new project is set up, a suitable microcontroller, PIC16F877A is
chosen as shown in Figure 4.1(c).
Figure 4.1 (c) Device Selection
When the correct device is selected, the HI-TECH C compiler is appeared
like shown in Figure 4.1(d).
Figure 4.1(d) Active Tool suite
Then create a new project file by given a name “remote control” and browse
it location.
Figure 4.1(e) Project name and Browse
After we add the program in text file to the existing file, the final parameters
with configuration will be obtain. Figure 4.1(f) show how to add the text file while
the Figure 4.1(g) is the project parameters.
Figure 4.1(f) File Adding
Figure 4.1(g) Project parameter
The project then is ready to be build as shown is Figure 4.1(h).
Figure 4.1 (h) Build the project
MPLAB 7.62 generates a *hex file that will be transferred to the
PIC16F877A using the bootloader. There are some other changes when using C
programming PICC Lite compiler. There must be offset 200h in the Linker option as
shown in Figure 4.1(i) and Figure (j). the offset 200h is to set the staring address of
our program so that it will not overlap with the firmware program in PIC16F877A as
this create reset vector error during bootloader process.
Figure 4.1(i) Build option
Figure 4.1(j) Linker option
4.4 Bootloader with Hyper Terminal
From the MPLAB 7.62, the program is ready and a *.hex file is generated.
Bootloader is used to load the program into SK40A. There are several procedures
before the loading process. The PIC16F877A is plugged in and the position is checked
to be correct. Power is provided to the start up kit. A serial cable is used to connect the
start up kit and the serial port of the computer as shown in Figure 4.2
Figure 4.2 Preparation for bootloader
Hyper Terminal is the software available in all windows. This program is
launched from “Start - All Program - Accessories - Communications –
HyperTerminal”. The name (Bootloader) of the connection is given and icon is
selected as shown in Figure 4.3(a), followed by serial communication port selection
(COM1) as illustrated in Figure 4.3(b)
n
Figure 4.3(a) New connection
Figure 4.3(b) Connect using COM1
Some details about the communication port properties are modified as shown in
Figure 4.3(c).
• Bits per second : 9600
• Data bits : 8
• Parity : None
• Stop bit :1
• Flow control : None
Figure 4.3(c) COM1 Properties
Next, two steps needed to change the character delay. First, select “Call -
Disconnect”. Second, select “File - Properties - Setting” and go into “ASCII Setup”
submenu. The character delay is changed to 10miliseconds as illustrated in Figure
4.3(d) and Figure 4.3(e).
The connection is saved with filename preferred and the Hyper Terminal is
closed. The connection file saved is launched again from “Start - All Programs -
Accessories – Communication – Hyper Terminal - *.ht”. For SK40A to enter the boot
mode and wait for hex file, press and hold down the “Boot” button then press the
“Reset” button. The “Reset” button is released before release the “Boot” button. Once
the buttons are released, the wording www.cyctron.com.my will appear on the screen
as shown in figure 4.3(f). The *.hex file is transferred to the PIC16F877A through
“Transfer - Send Text File” and select “All files” from “Files of type”. The *.hex file
of program which is already complied and generated using MPLAB 7.62 is selected.
This process might take a couple minutes depending on the program length. When the
transfer is successful, the wording “Done! Reset PIC to run” will appear on the screen
as shown in Figure 4.3(g).
Figure 4.3(f) Bootloader started
Figure 4.3(g) Bootloader ended
4.5 Source Code
The complete program with comments of this remote control system is shown
like Figure 4.8 below. The program is written in C language.
Figure 4.4 Source Code
CHAPTER V
RESULTS AND DISCUSSION
5.1 Overview
For this chapter, some result obtained from the project testing were summarized
and discussed. The main important outcome of this project was the establishment of the
sound record and the functionality of this remote control system.
5.2 Result
Table 5.1 Result
ISD 2560 PIC 16F877A
Stage 1 Message Recorded/Play back PIC Idle
Stage 2 Non Message Recorded
PIC operate fellow in
instruction
‘1’- LED 1 will on
‘2’-LED 1 and 2 will on
All the operation depend
on my program
*LED 1 represent TV
*LED 2 represent HI- FI
As mentioned, the result of the system will be more focused on the signal
received by the infrared receiver and output quality of the ISD2560. With refer to the
table above, the system actually consists of two path: remote control and sound record.
3 switches in the system will use to control its function. With refer to the figure 5.1
below with more easy understand how this 3 switch control.
START
Switch 1 ON?
Yes No
Switch 2 will on the
LED1 (TV) OR
Switch 3 will on the LED2(TV) and LED3(HI-FI)
• Recording/Play back • Remote control will
do nothing.
END
Figure 5.1 Flow of the system
5.3 Discussions
From the results, there were several clarifications and extra points that can
be summarized. Some main features of the system were discussed as well.
1. The PIC16F877A is providing a good in control the whole system
and it was friendly used.
2. Only 2 devices were implementing in this remote control system. So,
the LED 1 and 2 can be turned ON/OFFT controlled by the switch.
3. There is almost no delay occurred in the remote control system. The
command issued from the user was executed within un-detectable
delay.
4. Since the remote control system involves infrared, so the distance
between transmit infrared and Rx is around 6cm and must in light of
sight (LOS).
5. The angle range for Rx infrared is about 24° and this has different
with the accurate value.
6. The sound quality during playback on this device was found to be
greatly depending on the microphone and the speaker that were used
in the circuit. When using a higher quality microphone and speaker,
we found that the sound quality was very good.
7. Adapter 5V/0.5A suitable for using in this system for providing the
stable power supply.
5.4 Problems Encountered
There are several problems that occurred in the progress of the accomplishing
the project, however, all the problems were solved and the system has been improved.
1. The program has to written as short as possible. Many modifications are
made in hardware configuration and connection to keep the code simple.
2. There are many components very different from the design. So we has
to find out the datasheet and understand the features of that component.
3. Unstable power supply was solved but putting the 5V/0.5A adapter to
make sure the system work properly.
CHAPTER VI
CONCLUSION
6.1 Overview
This chapter is to provide a summary of the project done and some future
improvements that can be made to enhance the system.
6.2 Conclusion
As the conclusion, the system performs as desired. The prototype developed
was easy to operate and very user friendly. The system not only can for message
recording, but also can control the electrical devices. Beside that, through this system
people can record the reminder instead of writing on a paper. The number of remote
control can also be reducing as by using this all in one remote control.
There are some improvements that can be made to further enhance the system
as listed below.
1. Amplifier circuit can be added to provide better voice reproduction with
least noise.
2. The ISD2560 can be connected to voice recognition IC HM2007 to help
people with talking disabilities. The ISD2560 will be pre-recorded with
several most commonly used phrases and the HM2007 will be trained to
be recognize some short phrase by the user.
3. The switches in the system can replace by using Bluetooth to make the
system easier to control.
4. Replace the infrared with Bluetooth technology for overcome short
distance transmissions and line of sigh (LOS).
In short, the project developed was able to provide satisfaction and comfort to
users. The features of current remote control system in many aspects were enhanced to
provide best solution to user in their daily life problems. So, the objectives of the
project were achieved. This project has been completed in two semesters. Although the
project was performing well but some improvements as stated above were necessary in
the future. So, all information in this project may be used for future work of research
and improvement to fulfill an engineer’s duty that is to provide human welfare and
public interest.
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APPENDIX A
ISD 2560 Voice Record/Playback Device
APPENDIX B
Device Operation
APPENDIX C
Operation Modes
