Housekeep

1. INTRODUCTION

1.1 HISTORY

The notion of robots or robot-like automates can be traced back to

medieval times. Although people of that era didn’t have a term to describe what

we would eventually call a robot they were nevertheless imagining mechanisms

that could perform human-like tasks.

In medieval times, automatons, human-like figures run by hidden

mechanisms, were used to impress peasant worshippers in church into believing

in a higher power.

The automatons, like the clock jack pictured here,

created the illusion of self-motion (moving without

assistance). The clock jack was a mechanical figure that could

strike time on a bell with its axe. This technology was virtually

unheard of in the 13th century. So imagine how awe inspiring

an automaton was to someone just like you!

In the 18th century, miniature automatons became

popular as toys for the very rich. They were made to look

and move like humans or small animals. The pretty

musician in the picture was built around 1890. She can turn

her head from side to side while playing the instrument

with her hands and keeping time with her foot.

In literature, humankind’s vivid imagination has

often reflected our fascination with the idea of creating artificial life. In 1818,

Mary Shelly wrote Frankenstein, a story about the construction of a human-like

creature.

For Shelly, a robot looked like man but had the ability to function like a

machine. It was built of human components, which could be held together by

nuts and bolts. Notice there are even clips to hold the top of the head together!

Shelly considered that a robot had to be bigger than a regular person and had to

have super human strength.

In 1921, Karel Capek, a Czech playwright, came up with an intelligent,

artificially created person, which he called “robot”. The word “robot” is Czech

for worker, and was gradually incorporated into the English language without

being translated. As you can see, even a hundred years after Shelly’s

Frankenstein, Capek’s idea of a robot is still one in which the creation

resembles the human form.

While the concept of a robot has been around for a very long time, it

wasn’t until the 1940’s that the modern day robot was born, with the arrival of

computers. The term robotics refers to the study and use of robots; it came

about in 1941 and was first adopted by Isaac Asimov, a scientist and writer.

It was Asimov who also proposed the following “Laws of Robotics” in

his short story Runaround:

1st law: A robot may not injure a human being or through inaction, allow a

human being to come to harm.

2nd law: A robot must obey the orders given it by human beings except where

such orders would conflict with the first law.

3rd law: A robot must protect its own existence as long as such protection does

not conflict with the First or Second Laws.

The robot really became a popular concept during the late 1950’s and

early 1960’s. With the automotive industry in full expansion at that time,

industrial robots were employed to help factory operators.

Industrial robots do not have the imaginative, human-like appearance that

we have been dreaming of throughout the ages. They are computer-controlled

manipulators, like arms and hands, which can weld or spray paint cars as they

roll down an assembly line.

1.2 NEED OF HOUSE KEEPING ROBOT:

Often, robots are used to do jobs that could be done by humans. However,

there are many reasons why robots may be better than humans in performing certain

tasks.

Speed

Robots may be used because they are FASTER than people at carrying out

tasks. This is because a robot is really a mechanism which is controlled by a computer

- and we know that computers can do calculations and process data very quickly.

Some robots actually MOVE more quickly than we can, so they can carry out a

task, such as picking up and inserting items, more quickly than a human can.

Hazardous (dangerous) Environments

Robots may be used because they can work in places where a human would be

in danger. For example, robots can be designed to withstand greater amounts of

heat

radiation,

chemical fumes

Than humans could.

Efficiency

Efficiency is all about carrying out tasks without waste. This could

mean

not wasting time

not wasting materials

not wasting energy

Repetitive Tasks

Sometimes robots are not really much faster than humans, but they are good at

simply doing the same job over and over again. This is easy for a robot, because once

the robot has been programmed to do a job once, the same program can be run many

times to carry out the job many times. And the robot will not get bored as a human

would.

Accuracy

Accuracy is all about carrying out tasks very precisely. In a factory

manufacturing items, each item has to be made identically. When items are being

assembled, a robot can position parts within fractions of a millimetre.

Adaptability

Adaptability is where a certain robot can be used to carry out more than one

task. A simple example is a robot being used to weld car bodies. If a different car

body is to be manufactured, the program which controls the robot can be changed.

The robot will then carry out a different series of movements to weld the new car

body.

1.3 SYSTEM OVERVIEW:

The different units present in House Keeping Robot are as follows:-

Automatic vacuum cleaner

Robotic arm and its control circuitry

Input section :

Voice recognition module

Robotic control through mobile using DTMF

RF control

Hazard detection unit.

Output section

LCD display

Buzzer

Voice recording and playback

Transmitter section.

Power supply unit.

1.4 BLOCK DIAGRAM:

1.4.1 Block Diagram of House Keeping Robot

1.4.2 Block Diagram of Transmitter Section:

MICROCONTROLLER

P89V51RD2

DTMF RECEIVER

& DECODER

RF RECEIV

ER

VOICE RECOGNITI

ON MODULE

OBSTACLE DETECTION SENSOR

M

MDC MOTOR DRIVER

H - BRIDGE

RELAY

DRIVER

VACCUM

CLEANER

ENCODERH12 E

INPUT FROM

SWITCHES

RF TRANSMI

TTER

1.4.2 Block Diagram of Servo Arm:

1.4.2 Block Diagram of Hazard Detection Unit:

MICROCONTROLLER

AT89S52

SERVOMOTOR DRIVER

SERVOMOTOR

FOR ROBOTIC

ARM

RF RECEIVE

R

MICROCONTROLLER

AT89S52

INPUT FROM

SENSORS LPG, FIRE SMOKE, TEMP.,

INPUT FROM

SWITCHES

LCD 16X2

GSM MODEMSIM 300

BUZZER

2. LITERATURE SURVEY

Even though the market size is still small at this moment, applied fields

of robots are gradually spreading from the manufacturing industry to the others

in recent years. One can now easily expect that applications of robots will

expand into the first and the third industrial fields as one of the important

components to support our society in the 21st century.

There also raises strong anticipations in many countries that robots for the

personal use will coexist with humans and provide supports such as the

assistance for the housework, care of the aged and the physically handicapped,

since Japan is the fastest aging society in the world.

Service robots are emerging from the laboratory as commercial products.

Floor cleaning, material transporting in radioactive and other hostile

environments and security robots are some of the facets of a service robot. This

project focuses on one such service robot for housekeeping purposes, the

concept and a design aspect of the developed robot is presented.

The design philosophy that emphasizes compromise and practicality in

design is being explained. This philosophy is used in the design and integration

of a housekeeping robot system and sensor systems to provide new functionality

for the user. The robot navigation problem is solved through a hybrid sensor

system. The developed robot system comprises of a mobile platform, hybrid

sensor system and a gripper system. This project report also discusses the

design concepts and realization of a housekeeping robot to perform picking and

placing tasks.

3. ELECTRONICS

3.1 Microcontroller P89V51RD2:

The P89V51RD2 is an 80C51 microcontroller with 64 kB Flash

and 1024 bytes of data RAM. A key feature of the P89V51RD2 is its X2 mode

option. The design engineer can choose to run the application with the

conventional 80C51 clock rate (12 clocks per machine cycle) or select the X2

mode (6 clocks per machine cycle) to achieve twice the throughput at the same

clock frequency.

Another way to benefit from this feature is to keep the same performance

by reducing the clock frequency by half, thus dramatically reducing the EMI.

The Flash program memory supports both parallel programming and in

serial In-System Programming (ISP). Parallel programming mode offers gang-

programming at high speed, reducing programming costs and time to market.

ISP allows a device to be reprogrammed in the end product under

software control. The capability to field/update the application firmware makes

a wide range of applications possible.

The P89V51RD2 is also In-Application Programmable (IAP), allowing

the Flash program memory to be reconfigured even while the application is

running.

Features:

1. 80C51 Central Processing Unit2. 5 V Operating voltage from 0 to 40 MHz3. 64 kB of on-chip Flash program memory with ISP (In-System

Programming) and4. IAP (In-Application Programming)5. Supports 12-clock (default) or 6-clock mode selection via software

or ISP

6. SPI (Serial Peripheral Interface) and enhanced UART7. PCA (Programmable Counter Array) with PWM and

Capture/Compare functions8. Four 8-bit I/O ports with three high-current Port 1 pins (16 mA

each)9. Three 16-bit timers/counters10. Programmable Watchdog timer (WDT)11. Eight interrupt sources with four priority levels12. Second DPTR register13. Low EMI mode (ALE inhibit)14. TTL- and CMOS-compatible logic levels

3.1.1 Pin Configuration of 89V51RD2:

3.1.2 Block diagram:

3.1.3 Pin Details:

89V51RD is 40 pin IC with four ports. Pin diagram of microcontroller is shown

in Fig.

VCC - - Supply voltage..

VSS - - Ground.

Port 0Port 0

Port 0 is an 8-bit open-drain bi-directional I/O port. As an output port, each pin

can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as

high impedance inputs. Port 0 may also be configured to be the multiplexed low

order address/data bus during accesses to external program and data memory. In this

mode P0 has internal pull-ups. Port 0 also receives the code bytes during Flash

programming, and outputs the code bytes during program verification. External pull-

ups are required during program verification.

Port 1 Port 1

Port 1 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 1 output

buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins they are

pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 1 pins

that are externally being pulled low will source current (IIL) because of the internal

pull-ups. Port 1 also receives the low-order address bytes during Flash programming

and verification.

Port 2Port 2

Port 2 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 2 output

buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins they are

pulled high by the internal pull-ups and can be used as inputs. As inputs, Port 2 pins

that are externally being pulled low will source current (IIL) because of the internal

pull-ups. Port 2 emits the high-order address byte during fetches from external

program memory and during accesses to external data memory that uses 16-bit

addresses (MOVX @ DPTR). In this application, it uses strong internal pull-ups

when emitting 1s. During accesses to external data memory that uses 8-bit addresses

(MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2

also receives the high-order address bits and some control signals during Flash

programming and verification.

Port 3Port 3

Port 3 is an 8-bit bi-directional I/O port with internal pull-ups. The Port 3

output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins

they are pulled high by the internal pull-ups and can be used as inputs. As inputs,

Port 3 pins that are externally being pulled low will source Current (IIL) because of

the pull-ups. Port 3 also serves the functions of various special features of the

AT89V51RD2 as listed:

P3.0 RXD (serial input port)

P3.1 TXD (serial output port)

P3.2 INT0 (external interrupt 0)

P3.3 INT1 (external interrupt 1)

P3.4 T0 (timer 0 external input)

P3.5 T1 (timer 1 external input)

P3.6 WR (external data memory write strobe)

P3.7 RD (external data memory read strobe)

Port 3 also receives some control signals for Flash programming and verification.

RST –RST –

Reset input. A high on this pin for two machine cycles while the oscillator is

running resets the device.

ALE/ PROGALE/ PROG

Address Latch Enable output pulse for latching the low byte of the address

during accesses to external memory. This pin is also the program pulse input

(PROG) during Flash programming. In normal operation ALE is emitted at a

constant rate of 1/6 the oscillator frequency, and may be used for external timing or

clocking purposes. Note, however, that one ALE pulse is skipped during each access

to external Data Memory. If desired, ALE operation can be disabled by setting bit 0

of SFR location 8EH. With the bit set, ALE is active only during a MOVX or

MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-

disable bit has no effect if the microcontroller is in external execution mode.

PSENPSEN

Program Store Enable is the read strobe to external program memory. When the

89V51RD2FA is executing code from external program memory, PSEN is activated

twice each machine cycle, except that two PSEN activations are skipped during each

access to external data memory.

EA/VPP EA/VPP

External Access Enable. EA must be strapped to GND in order to enable the

device to fetch code from external program memory locations starting at 0000H up

to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally

latched on reset. EA should be strapped to VCC for internal program executions.

This pin also receives the 12-volt programming enable voltage (VPP) during Flash

programming, for parts that require 12-volt VPP.

3.1.4 Oscillator and Clock Details:3.1.4 Oscillator and Clock Details:

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock

operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

3.1.5 Transmission in 89V51RD2::

89V51RD2 has a serial data communication circuit that uses register SBUF to

hold data. Register SCON controls data communication. Register PCON controls

data rates. Pins RxD (p3.0) and TxD(3.1) connect to serial data network. SBUF is

physically two registers, one is writing only i.e. to hold data to be transmitted out of

microcontroller via TxD. The other is read only and holds received data from an

external transmitting source via RxD.

Whenever a data byte is transmitted T1 flag is set and so program is interrupted

to transmit another byte of data. The main program is interrupted only serial port

interrupt is 1E SFR is enable.

The data transmission steps are:

Initially the T1 flag is reset.

Data to be transmitted must be written into SBUF.

As soon as data is transmitted the T1 flag is set and main program is

interrupted to execute ISR.

In the ISR T1 flag is reset .another data is written in SBUF register.

3.2 Microcontroller At89s52:

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller

with 8K bytes of in-system programmable Flash memory. The device is

manufactured using Atmel’s high-density nonvolatile memory technology and is

compatible with the indus-try-standard 80C51 instruction set and pinout. The on-

chip Flash allows the program memory to be reprogrammed in-system or by a

conventional nonvolatile memory pro-grammer. By combining a versatile 8-bit

CPU with in-system programmable Flash on a monolithic chip, the Atmel

AT89S52 is a powerful microcontroller which provides a highly-flexible and

cost-effective solution to many embedded control applications.

Features:

1. 8K Bytes of In-System Programmable (ISP) Flash Memory –

Endurance: 10,000 Write/Erase Cycles

2. 4.0V to 5.5V Operating Range

3. Fully Static Operation: 0 Hz to 33 MHz

4. Three-level Program Memory Lock

5. 256 x 8-bit Internal

6. 32 Programmable I/O

7. Three 16-bit Timer/Counters

8. Eight Interrupt Sources

9. Full Duplex UART Serial Channel • Low-power Idle and Power-down

Modes

10. Interrupt Recovery from Power-down Mode

11. Watchdog Timer

12. Dual Data Pointer

3.2.1 Block Diagram:

3.3 ADC 0804:

Analog to digital converters find huge application as an intermediate

device to convert the signals from analog to digital form. These digital signals

are used for further processing by the digital processors. Various sensors like

temperature, pressure, gas etc. convert the physical characteristics into electrical

signals that are analog in nature.

ADC0804 is a very commonly used 8-bit analog to digital convertor. It is

a single channel IC, i.e., it can take only one analog signal as input. The digital

outputs vary from 0 to a maximum of 255. The step size can be adjusted by

setting the reference voltage at pin9. When this pin is not connected, the default

reference voltage is the operating voltage, i.e., Vcc. The step size at 5V is

19.53mV (5V/255), i.e., for every 19.53mV rise in the analog input, the output

varies by 1 unit. To set a particular voltage level as the reference value, this pin

is connected to half the voltage. For example, to set a reference of 4V (Vref),

pin9 is connected to 2V (Vref/2), thereby reducing the step size to 15.62mV

(4V/255). 

ADC0804 needs a clock to operate. The time taken to convert the analog

value to digital value is dependent on this clock source. An external clock can

be given at the Clock IN pin. ADC 0804 also has an inbuilt clock which can be

used in absence of external clock. A suitable RC circuit is connected between

the Clock IN and Clock R pins to use the internal clock.

3.3.1 Pin Configuration of ADC 0804:

3.3.2 Pin Description: 

Pin Function Name

No1 Activates ADC; Active low Chip select

2 Input pin; High to low pulse brings the data from internal registers to the output pins after conversion

Read

3 Input pin; Low to high pulse is given to start the conversion

Write

4 Clock Input pin; to give external clock. Clock IN

5 Output pin; Goes low when conversion is complete Interrupt

6 Analog non-inverting input Vin(+)

7 Analog inverting Input; normally ground Vin(-)

8 Ground(0V) Analog Ground

9 Input pin; sets the reference voltage for analog input Vref/2

10 Ground(0V) Digital Ground

11

8 bit digital output pins

D712 D613 D514 D415 D316 D217 D118 D019 Used with Clock IN pin when internal clock source is

usedClock R

20 Supply voltage; 5V Vcc

3.4 MT 8870 (DTMF Decoder IC):

The MT8870D/MT8870D-1 is a complete DTMF receiver integrating

both the bandsplit filter and digital decoder functions. The filter section uses

switched capacitor techniques for high and low group filters; the decoder uses

digital counting techniques to detect and decode all 16 DTMF tone pairs into a

4-bit code.

External component count is minimized by on chip provision of a

differential input amplifier, clock oscillator and latched three-state bus interface.

Features:

1. Complete DTMF Receiver

2. Low power consumption

3. Internal gain setting amplifier

4. Adjustable guard time

5. Central office quality

6. Power-down mode

7. Inhibit mode

8. Backward compatible with

MT8870C/MT8870C-1

3.4.1 Block diagram of MT8870:

3.4.2 Pin Configuration of MT8870:

3.4.3 Pin Functions of MT8870:

3.5 HT12E Encoder IC:

HT12E is an encoder integrated circuit of 212 series of encoders. They

are paired with 212 series of decoders for use in remote control system

applications. It is mainly used in interfacing RF and infrared circuits. The

chosen pair of encoder/decoder should have same number of addresses and data

format.

 Simply put, HT12E converts the parallel inputs into serial output. It

encodes the 12 bit parallel data into serial for transmission through an RF

transmitter. These 12 bits are divided into 8 address bits and 4 data bits.

 HT12E has a transmission enable pin which is active low. When a trigger

signal is received on TE pin, the programmed addresses/data are transmitted

together with the header bits via an RF or an infrared transmission medium.

HT12E begins a 4-word transmission cycle upon receipt of a transmission

enable. This cycle is repeated as long as TE is kept low. As soon as TE returns

to high, the encoder output completes its final cycle and then stops.

3.5.1 Pin Configuration of HT12E:

3.5.2 Pin Functions of HT12E:

 Pin No

 Function  Name

1

8 bit Address pins for input

A02 A13 A24 A35 A46 A57 A68 A79 Ground (0V) Ground10

4 bit Data/Address pins for input

AD011 AD112 AD213 AD314 Transmission enable; active low TE15 Oscillator input Osc216 Oscillator output Osc117 Serial data output Output18 Supply voltage; 5V (2.4V-12V) Vcc

3.6 HT12D Decoder IC:

HT12D is a decoder integrated circuit that belongs to 212 series of

decoders. This series of decoders are mainly used for remote control system

applications, like burglar alarm, car door controller, security system etc. It is

mainly provided to interface RF and infrared circuits.  They are paired with

212 series of encoders. The chosen pair of encoder/decoder should have same

number of addresses and data format.

In simple terms, HT12D converts the serial input into parallel outputs. It

decodes the serial addresses and data received by, say, an RF receiver, into

parallel data and sends them to output data pins. The serial input data is

compared with the local addresses three times continuously. The input data code

is decoded when no error or unmatched codes are found. A valid transmission in

indicated by a high signal at VT pin.

HT12D is capable of decoding 12 bits, of which 8 are address bits and 4

are data bits. The data on 4 bit latch type output pins remain unchanged until

new is received.

3.6.1 Pin Configuration of HT12D:

3.6.2 Pin Function of HT12D:

 Pin No

 Function  Name

1

8 bit Address pins for input

A02 A13 A24 A35 A46 A57 A68 A79 Ground (0V) Ground10

4 bit Data/Address pins for output

D011 D112 D213 D314 Serial data input Input15 Oscillator output Osc216 Oscillator input Osc117 Valid transmission; active high VT18 Supply voltage; 5V (2.4V-12V) Vcc

3.7 GSM Modem (SIM 300)

The GSM unit contains a GSM module along with a GSM transmitter

antenna. The module functions according to its built and the antenna transmits

the information to the Base Station wherein this is exposed to further

processing. GPS is not a two-way system. It can either receive or transmit but

not both. Due to its inability in doing so, GSM systems are used.

The GSM module that we are using in this unit is the SIMCOM SIM300

module. Designed for global market, SIM300 is a Tri-band GSM/GPRS engine

that works on frequencies EGSM 900 MHz, DCS 1800 MHz and PCS1900

MHz. SIM300 provide RF antenna interface with two alternatives: antenna

connector and antenna pad. The antenna connector is MURATA MM9329-

2700. And customer’s antenna can be soldered to the antenna pad. The Picture

of a GSM modem used in this project is as shown below.

SMS is one of the unique features of GSM compared to older analog

systems. For point-to-point SMS, a message can be sent to another subscriber to

the service, and an acknowledgment of receipt is sent to the sender. SMS also

can be used in Cell Broadcast mode to send messages such as traffic or news

updates. Messages can be stored on the SIM card for later retrieval. SMS is

effective because it can transmit short messages within 3 to 5s via the GSM

network and doesn’t occupy a telephony channel. Moreover, the cost savings

makes it a worthwhile choice. With SMS transmitting, gathering position data is

easy and convenient.

We use AT commands to control and program the SIMCOM SIM300

module. The data and control commands are exchanged between the PIC

microcontroller and GSM module through the serial interface. There are many

groups of AT commands, including: Call Control, Data Card Control, Phone

Control, Computer Data Card Control, Reporting Operation, Network

Communication Parameter, Miscellaneous, and Short Message Service. We use

some of the SMS commands to communicate with the control center.

The main AT commands for using SMS are listed below.

A/                 -  Re-issues last AT command given

ATD              -  Mobile originated call to dialable number

ATH              – Disconnect existing connection

AT+CSCA    – Set the SMS center address. Mobile-originated messages

are transmitted through this service center.

AT+CMGS   – Send SMS command

AT+CMGF   – Select format for incoming and outgoing messages: zero

for PDU mode, one for Text  mode.

AT+CSMS    – Select message service

AT+CRES     – Restore SMS settings

AT+CSCB     – Select cell broadcast SMS messages

AT+CSDH    – Show SMS text mode parameters

Let’s review an example of how to make a GSM module send and read a

sample SMS in Text mode.

First, initialize the GSM module with AT commands AT+CSCA and

AT+CMGF. Using the former sets the SMS center number to be used with

outgoing SMS messages. Remember, the number will be saved on the SIM card

just like in normal mobile phones. There are two different modes—Text mode

and Protocol Data Unit (PDU) mode—for handling short messages. The system

default is PDU mode; however, Text mode is easier to understand. So, use the

AT+CMGF=1 command to set the module to the GSM 07.05 standard SMS

Text mode. The AT+CMGS command is used to send a short message. The

GSM module can receive incoming short messages and save them on the SIM

card automatically. You can use the AT+CMGR command to read an incoming

short message from the SIM card storage, and then use the AT+CMGD

command to delete it when you’re finished. If you want to read an SMS

message, then send an AT+CMGR=x command to tell the GSM module which

short message you want to read. Next, check the serial port to receive the

message from the GSM module.

3.8 LCD (16X2)

The output section

consists of the LCD Display

which is a 16character X

2line display used to

indicate the modes

selected, the clock time,

room temperature.

Etc.

The LCD Display mainly consists of two RAM

1) Display Data RAM (DDRAM)

2) Character Generator RAM (CGRAM)-User defined character

RAM

Display Data RAM (DDRAM)

Display data RAM (DDRAM) is where you send the characters (ASCII

code) you want to see on the LCD screen. It stores display data represented in 8-

bit character codes. Its capacity is 80 characters (bytes).  Below you see DD

RAM address layout of a 2*16 LCD.

In the above memory map, the area shaded in black is the visible display

(For 16x2 display).

For first line addresses for first 15 characters is from 00h to 0Fh. But for

second line address of first character is 40h and so on up to 4Fh for the 16th

character.

 So if you want to display the text at specific positions of LCD, we

require to manipulate address and then to set cursor position accordingly.

Character Generator RAM (CGRAM)-User defined character RAM

In the character generator RAM, we can define our own character patterns by

program. CG RAM is 64 bytes, allowing for eight 5*8 pixel, character patterns

to be defined. However how to define this and use it is out of scope of this

tutorial. So I will not talk any more about CGRAM

Registers

The HD44780 has two 8-bit registers, an instruction register (IR) and a data

register (DR). The IR stores instruction codes. The DR temporarily stores data

to be written into DDRAM or CGRAM and temporarily stores data to be read

from DDRAM or CGRAM. Data written into the DR is automatically written

into DDRAM or CGRAM by an internal operation. . These two registers can be

selected by the register selector (RS) signal. See the table below:

    Register Selection

RS R/W Operation

0 0 IR write as an internal operation (display clear, etc.)

0 1 Read busy flag (DB7) and address counter (DB0 to DB6)

1 0 DR write as an internal operation (DR to DDRAM or CGRAM)

1 1 DR read as an internal operation (DDRAM or CGRAM to DR)

Busy Flag (BF)

When the busy flag is 1, the LCD  is in the internal operation mode, and

the next instruction will not be accepted. When RS = 0 and R/W = 1 (see the

table above), the busy flag is output to DB7 (MSB of LCD data bus). The next

instruction must be written after ensuring that the busy flag is 0.

LCD Commands 

The LCD’s internal controller accept several commands and modify the

display accordingly. These commands would be things like:

– Clear screen

– Return home

– Shift display right/left

Instruction Decimal HEX

Function set (8-bit interface, 2 lines, 5*7 Pixels) 56 38

Function set (8-bit interface, 1 line, 5*7 Pixels) 48 30

Function set (4-bit interface, 2 lines, 5*7 Pixels) 40 28

Function set (4-bit interface, 1 line, 5*7 Pixels) 32 20

Scroll display one character right (all lines) 28 1E

Scroll display one character left (all lines) 24 18

Home (move cursor to top/left character position) 2 2

Move cursor one character left 16 10

Move cursor one character right 20 14

Turn on visible underline cursor 14 0E

Turn on visible blinking-block cursor 15 0F

Make cursor invisible 12 0C

Blank the display (without clearing) 8 08

Restore the display (with cursor hidden) 12 0C

Clear Screen 1 01

Set cursor position (DDRAM address) 128 +

addr

80+ addr

Set pointer in character-generator RAM (CG RAM

address)

64 + addr 40+ addr

Entry mode set

This command sets cursor move direction and display shift ON/OFF.

There are 4 possible function set commands;04, 05, 06, and 07. This command

changes the direction the cursor moves by setting the address counter to

increment or decrement. This command is very important. If you do not

understand it you may not see anything or what you actually wanted to see on

LCD screen.

Set cursor position (DDRAM address)

As said earlier if we want to display the text at specific positions of LCD,

we require to manipulate address and then to set cursor position accordingly.

If we want to display "Hi WELCOME" at the right corner of first line then I

should start from 10th character , So referring to table 80h+0Ah= 8Ah.

4. DESCRIPITION OF DIFFERENT UNITS

4.1 Automatic Vacuum cleaning unit:-

The main function of this unit is to automatically clean the house with the

help of an inbuilt vacuum cleaner that is attached to the base of the robot. The

basic block diagram of automatic vacuum cleaner is as shown below

The movement of the robot is achieved by using a D.C motor which is

used in differential drive as explained below

Differential drive is a method of controlling a robot with only two

motorized wheels. What makes this algorithm important for a robot builder is

that it is also the simplest control method for a robot. The term 'differential'

means that robot turning speed is determined by the speed difference between

both wheels, each on either side of your robot.

to drive straight both wheels move forward at same speed

to drive reverse both wheels move back at same speed

to turn left the left wheel moves in reverse and the right wheel moves forward

to turn right the right wheel moves in reverse and the left wheel moves forward

The DC motors used in this robot is a permanent magnet geared DC

Motors that has a speed of 60r.p.m and has a torque of 10kg-cm for a single DC

motor. Thus we have a total torque of 20kg because of two motors.

Once the clean mode is selected the microcontroller switches ON the

vacuum cleaner with the help of a relay. The relay is interfaced with the

microcontroller by the help of Darlington pair IC uln 2803. The robot identifies

the obstacles with the help of an obstacle detection sensor which is nothing but

the infrared sensor.

Three sensors are used one is attached in the front and the either two

sensors are attached in the right and left side of the robot. Whenever the sensor

is interrupted by a wall or a obstacle it interrupts the microcontroller, now

depending on the input from the sensor the corresponding motors are rotated to

achieve the desired turn. For example when a front and right side sensors are

interrupted the motor is driven to take a left turn by the microcontroller. In this

way any type of movement can be achieved depending on the state of the sensor

output.

The clean mode can be started with the help of a voice command, or

control from the handheld remote or through mobile phone. The time required

for cleaning can also be set by the microcontroller.

4.2 Robotic Arm and its Control Circuitry:-

In this project we use a robotic arm that has a gripper attached to it. Each

robotic arm has 4 servo motors for 4 degree of freedom and 1 servo motor

for the gripper. Each servo motor is controlled by the microcontroller which

receives command from the microcontroller. The main function of the

robotic arm is for picking and placing objects from one place to another.

Degrees of Freedom (DOF):-

The degrees of freedom or DOF, is a very important term to understand.

Each degree of freedom is a joint on the arm, a place where it can bend or

rotate or translate. we can typically identify the number of degrees of

freedom by the number of actuators on the robot arm. The actuators are the

servo motors which are responsible for the movement.

The robotic arm with 4 DOF is as shown below:

The basic block diagram is as shown below:-

The microcontroller drives the servo motor with the help of a driver

which nothing but a buffer IC that is used to prevent the loading effect of the

microcontroller since the source current of the microcontroller is very less as

compared to current required by servo motor.

What are Servo Motors?

Servo refers to an error sensing feedback control which is used to correct the

performance of a system. Servo or RC Servo Motors are DC motors

equipped with a servo mechanism for precise control of angular position.

The RC servo motors usually have a rotation limit from 90° to 180°. Some

servos also have rotation limit of 360° or more. But servos do not rotate

continually. Their rotation is restricted in between the fixed angles.

Servo Wiring 

All servo motor will have three wires: 

Black or Brown is for ground. 

Red is for power (~4.8-6V). 

Yellow, Orange, or White is the signal wire (3-5V).

Servo Voltage (Red and Black/Brown wires) 

Servos can operate under a range of voltages. Typical operation is

from 4.8V to 6V. There are a few micro sized servos that can operate at less,

and now a few Hitec servos that operate at much more. The reason for this

standard range is because most microcontrollers and RC receivers operate

MICROCONTROLLERSERVOMOTOR DRIVER

SERVOMOTOR

FOR ROBOTIC

ARM

near this voltage. So what voltage should you operate at? Well, unless you

have abattery voltage/current/power limitation, you should operate at 6V.

This is simply because DC motors have higher torque at higher voltages.

Signal Wire (Yellow/Orange/White wire) 

While the black and red wires provide power to the motor, the signal wire

is what you use to command the servo. The general concept is to simply send

an ordinary logic square wave to your servo at a specific wave length, and

your servo goes to a particular angle (or velocity if your servo is

modified).The wavelength directly maps to servo angle.

The standard time vs. angle is represented in this chart: 

Servo Current 

Servo current operates the same as in a DC motor, except that you now

also have a hard to predict feedback control system to contend with. If your

DC motor is not at the specified angle, it will suddenly draw huge amounts

of current to reach that angle. But there are other peculiarities as well. If you

run an experiment with a servo at a fixed angle and hang precision weights

from the servo horn, the measured current will not be what you expect. One

would think that the current would increase at some fixed rate as the weights

increased linearly. Instead you will get unpredictable curves and multiple

rates. 

Gear Types:-

More expensive servos come with metal gears for higher torque and longer

life, followed by karbonite and then nylon gears for the cheapest.

Nylon Gears - Nylon gears are most common in servos. They are extremely

smooth with little or no wear factors. They are also very lightweight, but

lack in durability and strength.

Karbonite Gears - Karbonite gears are relatively new to the market. They

offer almost 5 times the strength of nylon gears and also better wear

resistance. Cycle times of well over 300,000 have been observed with these

gears with virtually no wear. Servos with these gears are more expensive but

what you get in durability is more than equaled.

Metal Gears - Metal gears have been around for sometime now. Although

the heaviest and having the highest wear rate of all gear types, they offer

unparalleled strength. With a metal output shaft, side-loads can be much

greater. Ever had a nylon output shaft crack? I have. In applications that are

jarred around, metal gears are best. Unfortunately, due to wear, metal gears

will eventually develop slight play in the gear-train. Accuracy will slowly be

lost.

Velocity 

The servo turn rate, or transit time, is used for determining servo

rotational velocity. This is the amount of time it takes for the servo to move a

set amount, usually 60 degrees. For example, suppose you have a servo with

a transit time of 0.17sec/60 degrees at no load. This means it would take

nearly half a second to rotate an entire 180 degrees. More if the servo were

under a load. This information is very important if high servo response speed

is a requirement of your robot application. It is also useful for determining

the maximum forward velocity of your robot if your servo is modified for

full rotation. Remember, the worst case turning time is when the servo is at

the minimum rotation angle and is then commanded to go to maximum

rotation angle, all while under load. This can take several seconds on a very

high torque servo.

Efficiency and Noise 

Due to noise and control circuitry requirements, servos are less efficient

than DC motors uncontrolled. To begin with, the control circuitry typically

drains 5-8mA just on idle. Secondly, noise can more than triple current draw

during a holding position (not moving), and almost double current during

rotation.

4.3 INPUT SECTION UNIT:-

The movement of the robot can be controlled either by voice command,

or from the remote control, or by the mobile phone. It can also be controlled

automatically with the help of the sensor attached to it.

The different parts in the input section unit are as follows:-

Voice recognition module

Robotic control through mobile using DTMF

RF control

4.3.1 Voice recognition module:

The heart of the Voice Recognition Module is the Speech Recognition IC

HM2007. The HM2007 is a CMOS voice recognition LSI (Large Scale

Integration) circuit. The chip contains an analog front end, voice analysis,

regulation, and system control functions. The chip may be used in a stand alone

or CPU connected.

The voice recognition module is completely assembled and easy to use

programmable speech recognition circuit. Programmable, in the sense that you

train the words (or vocal utterances) you want the circuit to recognize. This

board allows you to experiment with many facets of speech recognition

technology. It has 8 bit data out which is interfaced with the microcontroller.

Some of interfacing applications which can be made are controlling robotics

movements, Speech Assisted technologies, Speech to text translation, and many

more.

The circuit will accept and recognize up to 20 words (numbers 1 through

20). It is not necessary to train all word spaces. If you only require 10 target

words that’s all you need to train. The time period for each word length is

around 1.92 seconds.

Features

• Self-contained stand alone speech recognition circuit

• User programmable

• Up to 20 word vocabulary of duration two second each

• Non-volatile memory back up with 3V battery onboard.

(Would keep the speech recognition data in memory even when power is

OFF)

• Easily interfaced to control external circuits & appliances

Specification:

Input Voltage - 9 to 15 V DC

Output Data - 8 bits at 5V Logic Level

Using the System:

The keypad and digital display are used to communicate with and

program the HM2007 chip. The keypad is made up of 12 normally open

momentary contact switches. When the circuit is turned on, “00” is on the

digital display, the red LED (READY) is lit and the circuit waits for a

command.

Training Words for Recognition:

Press “1” (display will show “01” and the LED will turn off) on the

keypad, then press the TRAIN key ( the LED will turn on) to place circuit in

training mode, for word one. Say the target word into the onboard microphone

(near LED) clearly. The circuit signals acceptance of the voice input by blinking

the LED off then on. The word (or utterance) is now identified as the “01”

word. If the LED did not flash, start over by pressing “1” and then “TRAIN”

key. You may continue training new words in the circuit. Press “2” then TRN to

train the second word and so on. The circuit will accept and recognize up to 20

words (numbers 1 through 20).

Testing Recognition:

Repeat a trained word into the microphone. The number of the word

should be displayed on the digital display. For instance, if the word “directory”

was trained as word number 20, saying the word “directory” into the

microphone will cause the number 20 to be displayed.

Error Codes:

The chip provides the following error codes.

55 = word too long

66 = word too short

77 = no match

Clearing Memory:

To erase all words in memory press “99” and then “CLR”. The numbers

will quickly scroll by on the digital display as the memory is erased.

Changing & Erasing Words:

Trained words can easily be changed by overwriting the original word.

For instances suppose word six was the word “Capital” and you want to change

it to the word “State”. Simply retrain the word space by pressing “6” then the

TRAIN key and saying the word “State” into the microphone. If one wishes to

erase the word without replacing it with another word press the word number

(in this case six) then press the CLR key. Word six is now erased.

Simulated Independent Recognition:

The speech recognition system is speaker dependant, meaning that the

voice that trained the system has the highest recognition accuracy. But you can

simulate independent speech recognition. To make the recognition system

simulate speaker independence one uses more than one word space for each

target word. Now we use four word spaces per target word.

Therefore we obtain four different enunciations of each target word.

(speaker independent). The word spaces 01, 02, 03 and 04 are allocated to the

first target word. We continue do this for the remaining word space. For

instance, the second target word will use the word spaces 05, 06, 07 and 08. We

continue in this manner until all the words are programmed.

If you are experimenting with speaker independence use different people

when training a target word. This will enable the system to recognize different

voices, inflections and enunciation's of the target word. The more system

resources that are allocated for independent recognition the more robust the

circuit will become. If you are experimenting with designing the most robust

and accurate system possible, train target words using one voice with different

inflections and enunciation's of the target word.

Homonyms are words that sound alike. For instance the words cat, bat,

sat and fat sound alike. Because of their like sounding nature they can confuse

the speech recognition circuit. While choosing target words for your system

don’t use homonyms.

The Voice with Stress & Excitement:

Stress and excitement alters ones voice. This affects the accuracy of the

circuit’s recognition. For instance assume you are sitting at your workbench and

you program the target words like fire, left, right, forward, etc., into the circuit.

Then you use the circuit to control a flight simulator game, Doom or Duke

Nukem. Well, when you’re playing the game you’ll likely be yelling

“FIRE! …Fire! ...FIRE!! ...LEFT …go RIGHT!”. In the heat of the action

you’re voice will sound much different than when you were sitting down

relaxed and programming the circuit. To achieve higher accuracy word

recognition one needs to mimic the excitement in ones voice when

programming the circuit. These factors should be kept in mind to achieve the

high accuracy possible from the circuit. This becomes increasingly important

when the speech recognition circuit is taken out of the lab and put to work in the

outside world.

Error Codes:

When interfacing the external circuit through its data bus, The decoding

circuit must recognize the word numbers from error codes. So the circuit must

be designed to recognize error codes

55, 66 and 77 and not confuse them with word spaces 5, 6 and 7.

Voice Security System

This circuit isn’t designed for a voice security system in a commercial

application, but that should not prevent anyone from experimenting with it for

that purpose. A common approach is to use three or four keywords that must be

spoken and recognized in sequence in order to open a lock or allow entry.

Aural Interfaces

It’s been found that mixing visual and aural information is not effective.

Products that require visual confirmation of an aural command grossly reduces

efficiency. To create an effective AUI products need to understand (recognize)

commands given in an unstructured and efficient methods. The way in which

the people typically communicate verbally.

Learning to Listen

The ability to listen to one person speak among several at a party is

beyond the capabilities of today’s speech recognition systems. Speech

recognition systems can not (as of yet) separate and filter out what should be

considered extraneous noise. Speech recognition does not understand speech.

Understanding the meaning of words is a higher intellectual function. Because a

circuit can respond to a vocal command doesn’t mean it understands the

command spoken. In the future, voice recognition systems may have the ability

to distinguish nuances of speech and meanings of words, to “Do what I mean,

not what I say!”

Speaker Dependent / Speaker Independent:

Speech recognition is divided into two broad processing categories;

speaker dependent and speaker independent. Speaker dependent systems are

trained by the individual who will be using the system. These systems are

capable of achieving a high command count and better than 95% accuracy for

word recognition. The drawback to this approach is that the system only

responds accurately only to the individual who trained the system.

This is the most common approach employed in software for personal

computers. Speaker independent is a system trained to respond to a word

regardless of who speaks. Therefore the system must respond to a large variety

of speech patterns, inflections and enunciation's of the target word. The

command word count is usually lower than the speaker dependent however high

accuracy can still be maintain within processing limits. Industrial applications

more often require speaker independent voice recognition systems.

Recognition Style:

In addition to the speaker dependent/independent classification, speech

recognition also contends with the style of speech it can recognize. They are

three styles of speech: isolated, connected and continuous. Isolated: Words are

spoken separately or isolated. This is the most common speech recognition

system available today.

The user must pause between each word or command spoken. Connected:

This is a half way point between isolated word and continuous speech

recognition. It permits users to speak multiple words. The HM2007 can be set

up to identify words or phrases 1.92 seconds in length.

This reduces the word recognition dictionary number to 20. Continuous:

This is the natural conversational speech we use to in everyday life. It is

extremely difficult for a recognizer to sift through the sound as the words tend

to merge together.

4.3.2 Robotic control through mobile using DTMF:-

Conventionally, wireless controlled robots user circuits, which have a

drawback of limited working range, limited frequency range and limited control. Use

of mobile phones for robotic control can overcome these limitations. It provides the

advantages of robust control, working range as large as the coverage area of the

service provider, no interference with other controllers and up to twelve controls.

The basic block diagram is as shown below:

In the project the robot is controlled by a mobile phone that makes a call to the

mobile phone attached to the robot. In the course of a call, if any button is pressed a

tone corresponding to the button pressed is heard at the other end called ‘Dual Tone

Multiple frequency’ (DTMF) tone. The robot receives these tones with help of phone

stacked in the robot. The received tone is processed by the microcontroller with the

help of DTMF decoder IC MT 8870. This IC sends a signal to the motor driver IC

l298d which drives the motor forward, reverse…etc

Dual-Tone Multi-Frequency (DTMF)

Dual-tone multi-frequency (DTMF) signaling is used for telephone signaling

over the line in the voice-frequency band to the call switching center. The version of

DTMF used for telephone tone dialing is known by the trademarked term Touch-

Tone, and is standardised by ITU-T Recommendation Q.23. Other multi-frequency

systems are used for signaling internal to the telephone network.

Keypad

The DTMF keypad is laid out in a 4×4 matrix, with each row representing a

low frequency, and each column representing a high frequency. Pressing a single key

such as '1' will send a sinusoidal tone of the two frequencies 697 and 1209 hertz (Hz).

The original keypads had levers inside, so each button activated two contacts. The

multiple tones are the reason for calling the system multifrequency. These tones are

then decoded by the switching center to determine which key was pressed.

1209 Hz  1336 Hz 1477 Hz 1633 Hz697 Hz 1 2 3 A

770 Hz 4 5 6 B

852 Hz 7 8 9 C

941 Hz * 0 # D

The M-8870 is a full DTMF Receiver that integrates both band split filter and

decoder functions into a single 18-pin DIP or SOIC package. Manufactured using

CMOS process technology, the M-8870 offers low power consumption (35 mW max)

and precise data handling. Its filter section uses switched capacitor technology for

both the high and low group filters and for dial tone rejection. Its decoder uses digital

counting techniques to detect and decode all 16 DTMF tone pairs into a 4-bit code.

External component count is minimized by provision of an on-chip differential input

amplifier, clock generator, and latched tri-state interface bus. Minimal external

components required include a low-cost 3.579545 MHz color burst crystal, a timing

resistor, and a timing capacitor.

The M-8870-02 provides a “power-down” option which, when enabled, drops

consumption to less than 0.5 mW. The M-8870-02 can also inhibit the decoding of

fourth column digits

The output of the decoder IC depending upon the input from the mobile

which produces a dual tone can be shown as follows:

From the above table it can be said that when a key no. 2 is pressed from

the mobile phone the decoder IC generates the four bit digital data output

corresponding to the mobile key no. 2 that is 0010. The digital data is now fed

to microcontroller to the required task.

4.3.3 RF Transmitter and Receiver Section:

The RF receiver and transmitter is used to control the robot using a remote

control which is the RF transmitter. The robotic movement can be changed with the

help of the hand held remote control which uses a RF module. The RF Module works

at the frequency of 434Mhz. The basic block diagram of transmitter and receiver

section is as shown below:

In the transmitter unit data is provided from the switches therefore the data is in

parallel form so this data should be converted into serial form. This can be achieved

with the help of an encoder, Hence Holtek encoder is used i.e. HT12E the output of

the HT12E IC is in serial form. It has a 12bit data output which comprises of 8 address

bits and four data bits.

The serial data is then transmitted through the transmitter RF module TWS

434. The module uses the Amplitude shift keying of the digital data and is then

transmitted in the space. The range of the transmission can be achieved at around 200

meters with the help of an antenna at a height of 30cm.

In the Receiver unit the antenna receives the signal of the frequency 434Mhz,

the receiver module RWS 434 converts the received signal into digital form which is

then decoded into data bits with the help of an decoder IC HT12D. The decoder IC

receives the data in serial form and converts the data in parallel form the data is then

fed to the microcontroller for further processing such as moving the robot or selecting

a particular mode of operation.

4.4 Hazard Detection Unit:

The main purpose of the hazard detection unit is to alert during some

hazardous conditions such as release of LPG gas, fire, release of smoke etc. For

this purpose different types of sensors are used in the robot. This unit also

displays the real time clock and also provides the function of Alarm.

This unit also displays the temperature of the room in a LCD display.

4.4.1 Gas detection:-

The release of LPG gas can be detected

with the help of a sensor called TGS 2600, where

the sensing element is comprised of a metal oxide

semiconductor layer formed on an alumina

substrate of a sensing chip together with an

integrated heater. In the presence of a detectable

gas, the sensor's conductivity increases depending

on the gas concentration in the air. A simple

electrical circuit can convert the change in conductivity to an output signal which

corresponds to the gas concentration.

The TGS 2600 has high sensitivity to low concentrations of gaseous air

contaminants such as hydrogen and carbon monoxide which exist in cigarette smoke.

The sensor can detect hydrogen at a level of several ppm. Figaro also offers a

microprocessor (FIC02667) which contains special software for handling the sensor's

signal for appliance control applications.

Due to miniaturization of the sensing chip, TGS 2600 requires a heater current

of only 42mA and the device is housed in a standard TO-5 package.

When LPG Gas releases the Robot alerts by providing a buzzer sound this

happens since the release of gas makes the resistance of the sensor low due to which it

provides a signal to the microcontroller and the microcontroller switches on the

buzzer. It also informs the user by sending a message to the user with the help of the

GSM Modem.

Features:

Low power consumption

High sensitivity to gaseous air contaminants

Long life and low cost

Uses simple electrical circuit

Small size

4.4.1 Fire detection & Temperature Monitoring:

The Temperature can be detected with the help of a temperature sensor

LM35.The LM35 series are precision integrated-circuit temperature sensors,

whose output voltage is linearly proportional to the Celsius (Centigrade)

temperature.

The LM35 does not require any external calibration or trimming to

provide typical accuracies of ±1⁄4°C at room temperature and ±3⁄4°C over a full

−55 to +150°C temperature range. Low cost is assured by trimming and

calibration at the wafer level. The LM35’s low output impedance, linear output,

and precise inherent calibration make interfacing to readout or control circuitry

especially easy. It can be used with single power supplies, or with plus and

minus supplies.

Features

Calibrated directly in ° Celsius (Centigrade)

Linear + 10.0 mV/°C scale factor

0.5°C accuracy guaranteeable (at +25°C)

Rated for full −55° to +150°C range

Suitable for remote applications

Low cost due to wafer-level trimming

Operates from 4 to 30 volts

Less than 60 μA current drain

Low self-heating, 0.08°C in still air

Nonlinearity only ±1⁄4°C typical

Low impedance output, 0.1 W for 1 mA load

The output of the LM35 acts as an input for the ADC 0804 which converts

the analog voltage into its digital equivalent. This digital value from the ADC is

processed by the microcontroller and displayed onto the display. When the

temperatures increases above 50 degree Celsius the microcontroller starts the

buzzer sound and also a message indicating the rise in temperature is sent to the

user with the help of a GSM modem.

4.5 Power Supply Unit:-

The power supply unit consists of battery and a regulator IC to provide

constant voltage for all the circuits employed in the robot. It also provides

supply to the Vacuum cleaner and all the motors.

The operating time of the robot is determined by the battery used in the

robot, so the battery should be selected properly. The battery selection is done

according to the power consumed by the motors and the circuits used in the

project then depending on the battery backup required the Ampere-hour rating

is selected.

A 2000mAH (= 2.0 AH) battery pack can power a robot with two drive

motors drawing 1A each continuously for up to 1 hour. Similarly, it can power a

robot with two drive wheels each consuming 0.5A for 2 hours (0.5 * 2 * 2).

Usually, higher capacity battery packs are physically larger.

Regulator IC

7805, 7812

BATTERY 12V 7.5Ah

TO ALL CIRCUITS

AND MOTORS

POWER SUPPLY UNIT

An important note is that battery packs rated at a specific capacity are not

always intended to be used at the maximum discharge rate. For example, a

battery pack rated at 5AH should not necessarily be discharged at 5A for 1

hour. It is suggest to add 20 to 40 percent extra capacity whenever possible, so

if your project requires 5A continuously, you should select a pack rated at 5AH

* 1.4 = 7AH. Remember to always check the rated peak discharge rate as

motors that are starting up consume significantly more current (around stall

current) when starting than when in operation.

Since most of the circuits enclosed operate on 5V, it is necessary to

provide a regulated 5v D.C. voltage. This can be achieved with the help of a

linear voltage regulator IC 7805 which is a voltage regulator integrated circuit.

It is a member of 78xx series of fixed linear voltage regulator ICs. The voltage

source in a circuit may have fluctuations and would not give the fixed voltage

output. The voltage regulator IC maintains the output voltage at a constant

value. The xx in 78xx indicates the fixed output voltage it is designed to

provide. 7805 provides +5V regulated power supply. Capacitors of suitable

values can be connected at input and output pins depending upon the respective

voltage levels.

7. PCB DESIGNING AND SOLDERING

7.1 PCB making

P.C.B. is printed circuit board which is of insulating base with layer

of thin copper-foil.

The circuit diagram is then drawn on the P. C. B. with permanent

marker and then it is dipped in the solution of ferric chloride so that

unwanted copper is removed from the P.C.B., thus leaving

components interconnection on the board.

The specification of the base material is not important to know in

most of the application, but it is important to know something about

copper foil which is drawn through a thin slip.

The resistance of copper foil will have an affect on the circuit

operation.

Base material is made of lamination layer of suitable insulating

material such as treated paper, fabric; or glass fibers and binding

them with resin. Most commonly used base materials are formed

paper bonded with epoxy resin.

It is possible to obtain a range of thickness between 0.5 mm to 3 mm.

Thickness is the important factor in determining mechanical strength

particularly when the commonly used base material is “Formea”

from paper assembly.

Physical properties should be self supporting these are surface

resistivity, heat dissipation, dielectric, constant, dielectric strength.

Another important factor is the ability to wishstand high temperature.

7.2 Designing the Layout

While designing a layout, it must be noted that size of the board

should be as small as possible.

Before starting, all components should be placed properly so that

an accurate measurement of space can be made.

The component should not be mounted very close to each other or

far away from one another and neither one should ignore the fact that

some component reed ventilation, which considerably the dimension

of the relay and transformer in view of arrangement, the bolting

arrangement is also considered.

The PCB layout is designed using the software PCB wizard 3.

Features of PCB Wizard 3 software

Designing Circuit Boards:

PCB Wizard 3 is both easy to learn and easy to use. To design a circuit

board, simply drag and drop components onto your document and connect them

together using the intelligent wiring tool. Then select the menu option 'Convert

to PCB' and leave PCB Wizard 3 to do the rest for you.

Component Placement & Automatic Routing

Strategic component placement is critical to achieving successful routing and

PCB Wizard 3 has been greatly enhanced in this area. The process is now fully

automated and PCB Wizard 3 is able to calculate an optimum board size for you

and intelligently position components in preparation for automatic routing.

Copper Pour

PCB Wizard 3 features a powerful new copper pour system that can help to

reduce your manufacturing costs by minimizing the amount of etching solution

required. To use it, all you have to do is insert a copper area on your board and

any pad or track inside the selected area will be automatically surrounded with a

gap of the desired size. As you update your design, the copper area is re-

calculated.

The layout is first drawn on paper then traced on copper plate which is

finalized with the pen or permanent marker which is efficient and

clean with etching.

The resistivity also depends on the purity of copper, which is highest

for low purity of copper. The high resistance paths are always

undesired for soldered connections.

The most difficult part of making an original printed circuit is the

conversion from, theoretical circuit diagram into wiring layout.

Without introducing cross over and undesirable effect.

Although it is difficult operation, it provides greater amount of

satisfaction because it is carried out with more care and skill.

The board used for project has copper foil thickness in the range of 25

40 75 microns.

The soldering quality requires 99.99% efficiency.

It is necessary to design copper path extra large. There are two main

reasons for this,

i) The copper may be required to carry an extra large overall

current:-

ii) It acts like a kind of screen or ground plane to minimize the

effect of interaction.

The first function is to connect the components together in their right

sequence with minimum need for interlinking i.e. the jumpers with

wire connections.

It must be noted, that when layout is done, on the next day it should be

dipped in the solution and board is move continuously right and left

after etching perfectly the board is cleaned with water and is drilled.

After that holes are drilled with 1 mm or 0.8 mm drill. Now the

marker on the P. C. B. is removed.

The Printed Circuit Board is now ready for mounting the components

on it.

7.2.1 PCB LAYOUT OF MOTOR DRIVER

7.2.2 PCB LAYOUT OF MICROCONTROLLER BOARD

7.2.3 PCB LAYOUT OF ADC 0804 BOARD

7.2.4 PCB LAYOUT OF RF TRANSMITTER

7.2.5 PCB LAYOUT OF RF

RECEIVER

7.2.6 PCB LAYOUT OF REMOTE

7.3 Soldering

For soldering of any joints first the terminal to be soldered are cleaned

to remove oxide film or dirt on it. If required flux is applied on the

points to be soldered.

Now the joint to be soldered is heated with the help of soldering iron.

Heat applied should be such that when solder wire is touched to joint,

it must melt quickly.

The joint and the soldering iron is held such that molten solder should

flow smoothly over the joint.

When joint is completely covered with molten solder, the soldering

iron is removed.

The joint is allowed to cool, without any movement.

The bright shining solder indicates good soldering.

In case of dry solder joint, a air gap remains in between the solder

material and the joint. It means that soldering is improper. This is

removed and again soldering is done.

In this way all the components are soldered on P. C. B.

7.4 Original Photos after soldering:

Microcontroller Board:

Motor Driver Circuit:

RF Receiver Circuit:

ADC Circuit:

RF Remote and RF Transmitter Circuit: