monomobile project file

8/11/2019 Monomobile Project File

1/38


2/38

Monomobile

Page 2of 38

CONTENTS

Problem Profile 1 to 3

General Block Diagram 4 to 5

Hardware Description6 to 7

Motors8 to 13

Voltage Regulator14 to 15

Motor Driver16 to 21

Wireless Communication 22 to 26

Diodes27 to 29

Chain Drive 30 to 31

Applications33

Conclusion34

Appendix I: Bibliography38

Appendix II: List of Figures39


3/38

Monomobile

Page 3of 38

ACKNOWLEDGEMENT

We express our gratitude to the Punjab Technical University, Jalandhar, for giving us the opportunity

to work on the major project during our final year of B. Tech. Project work is an important aspect in

the field of engineering.

It is not until you undertake projects like these that you realize how massive the effort it really is, or

how much you must rely upon the selfless efforts and goodwill of others. There are many who helped

us with these projects, and we want to thank them all.

We would like to thank Dr. S C Laroiya, Director, Rayat Institute of Engineering andInformation Technology, Railmajrafor his kind support. Our special thanks to Prof. R S Gupta ,

HOD, Mechanical Engineering, for his invaluable guidance throughout our project work.

We specially thankProf. Ishwinder Singhproject guide, whos invaluable guidance in this difficult

and endeavour period has provided us with the requisite motivation to complete our project

successfully.

We specially appreciate the help and guidance all those people who have directly or indirectly helped

us making our project a success.

PROJECT ASSOCIATES


4/38

Monomobile

Page 4of 38

Chapter 1: Problem Profile

INTRODUCTION

The idea behind this project is to design an MONOMOBILE (Motion Sensor Operated Wheel

Chair) is to help quadriplegic patient, who cannot move without help from others. This

MONOMOBILE gives them freedom to move on their own.

Although the appearance and capabilities of robots vary vastly, all robots share the features of

a mechanical, movable structure under some form of control. The control of robot involves

three distinct phases: perception, processing and action, generally, the preceptors are sensors

mounted on the robot, processing is done by the on board microcontroller or processor, and

the task (action) is performed using motors with some other actuators.

PROJECT WORKING

In our project we have to design a tilt communicator system for the Quadriplegic patient who

is suffering from damage in the spinal cord. Quadriplegics are limited in their motion and

need some device to communicate with their wheel chair for mobility without others

assistance. Providing the quadriplegics with movement and help them to be more

independent is the main goal of the project.

The tilt communicator is designed with artificial intelligence and embedded to provide a

communication between the patient and the wheel chair through the tilt movements of the

hand. In the tilt controller wheel chair, an accelerometer is used to produce an digital voltage

output (0 or 1) based on the specified tilt of the hand movement viz. front, back, right or left.

This digital output will be made available to the RF transmitter as an input using a logic

designed with the help of diodes and relays for the four respective directions of controlling.

An RF receiver system using 434 MHz frequency oscillator is used at the receiver section

that provides a real time controller to the wheel chair to control the motion in the desired

direction by calculating the intended direction of the head movement.


5/38

Monomobile

Page 5of 38

PROJECT OVERVIEW

Electronics Parts:

The electronics of hand tilt operated wheel chair govern data transfer between the server andthe robot, the control of two D.C motors, wireless link at the receivers side. All electronic

modules are supplied power by a distributed power supply which steps down voltages to

levels required by various electronic modules.

Mechanical Assembly:

Mechanical designing of this robot would be involving testing on different kinds of chassis

for the robot strong enough to carry a laptop and an easy drive using gear reduction and

worm wheel assembly.

1. Dimensional requirements:

Although the dimensions of the area on floor covered by the robot are not such a major

factor, the factors that we would consider while finalizing the size are The area required by

the different parts to be placed viz. PCBs, Battery, Camera assembly.

2. Weight Considerations

The estimated total weight of the robot would be about required to be around 100 kg

therefore the D.C. motors chosen for driving the robot were to be powerful enough to carry

the weight and not lock while turning.

Chain drive system is used with the motor to provide the enough torque to carry the

weight around 100 kg.

3. Reliability of design

When the idea of this robot was conceived it was decided that this robot and all its parts be

made very reliable .Therefore the entire structure would be put in place by tightening


6/38

Monomobile

Page 6of 38

multiple screws and bolts, and welded joints are also include, making it extremely reliable

and available for fine adjustments with great precision.

4. Strength required

The strength of the robot in terms of the strength of design would be optimized while taking

into account the conditions the wheel chair has to operate in.

5. Plug and play

The ease of any plug and play design has been well accomplished in case of the computers

used around the world. At the time while the idea of this robot was being conceived one of

the major plus points was to use a design conforming to the plug and play idea used in

todays computers. The advantages of this terminology of design are:

A. Ease of servicing / reparability of parts

B. Ease of maintenance

C. Improved reliability


7/38

Monomobile

Page 7of 38

Chapter 2: General Block Diagram

Block Diagram Of Tr ansmitter

Fig. I


8/38

Monomobile

Page 8of 38

BLOCK DIAGRAM OF RECEI VER

Fig II


9/38

Monomobile

Page 9of 38

Chapter 3 : Hardware Description

L ist Of Components used:

S.NO Name Quantity Colour/Material Pins

1 Chassis (mechanical) 1 Mild Steel -

2 RF modules 1 - -

3 Wheels for robot 4 2- cycle wheels

2- caster wheel

-

4 Motors 2 DC Geared (60rpm) -

5 Relays 1 - 5

6 Motor Driver L293D

( H-Bridge)

1 Black 16

7 Diodes

8 Designed PCB 1 -

9 Nut-Bolt Pair 8 -

10 Jumper Wire

( Single Stand Wire)

-

11 IC Base ( 8,14,16,40 pin) 3 Black -

12 Voltage regulator 7805 1 Black 3

13 Batteries 2 1- to drive motor

2- for circuit

-

14 10k ohm resistance 1 -


10/38

Monomobile

Page 10of 38

15 10 microfarad capacitor 1 -

Parts of Project:

The main parts of projects are:

7805 Voltage Regulator

Motors

Chassis

Motor Driving Circuits

Wireless Modules

Mercury Sensors

Comparator LM35 Motors

Construction detail s of project:

Overall dimensions: mm by mm Motor : 60 rpm

Wheels used: + Caster wheel

+ Cycle wheel

Sprockets Diameter on rear wheel :

Sprocket Diameter on front wheel :

Diameter of caster wheel:

Diameter of cycle wheel:

Batteries: 12 V


11/38

Monomobile

Page 11of 38

CHAPTER 4: MOTORS

Motor used in project: DC Geared ( 60 rpm)

Motor Description:

An electric motoris a type of machine that converts electrical energy into mechanical

energy. Electric motors operate through interacting magnetic fields and current-carrying

conductors to generate force, although a few use electrostatic forces. The reverse process,

producing electrical energy from mechanical energy, is accomplished by

an alternator, generator or dynamo. Many types of electric motors can be run as generators,

and vice versa. For example a starter/generator for a gas turbine or Traction motors used on

vehicles often perform both tasks.

Electric motors are found in applications as diverse as industrial fans, blowers and pumps,

machine tools, household appliances, power tools, and disk drives. They may be powered

by direct current(e.g., a battery powered portable device or motor vehicle), or by alternating

current from a central electrical distribution grid. The smallest motors may be found

in electric wristwatches. Medium-size motors of highly standardized dimensions and

characteristics provide convenient mechanical power for industrial uses. The very largest

electric motors are used for propulsion of large ships, and for such purposes as pipeline

compressors, with ratings in the millions of watts. Electric motors may be classified by the

source of electric power, by their internal construction, by their application, or by the type of

motion they give.

The physical principle of production of mechanical force by the interactions of an electric

current and a magnetic field was known as early as 1821. Electric motors of increasing

efficiency were constructed throughout the 19th century, but commercial exploitation of

electric motors on a large scale required efficient electrical generators and electrical

distribution networks.

Some devices, such as magnetic solenoids and loudspeakers, although they generate some

mechanical power, are not generally referred to as electric motors, and are usually

termed actuators and transducers, respectively.


12/38

Monomobile

Page 12of 38

The principle

The conversion of electrical energy into mechanical energy by an electromagnetic means was

demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was

dipped into a pool of mercury, on which a permanent magnet was placed. When a current was

passed through the wire, the wire rotated around the magnet, showing that the current gave

rise to a close circular magnetic field around the wire. This motor is often demonstrated in

school physics classes, but brine (salt water) is sometimes used in place of the toxic mercury.

This is the simplest form of a class of devices called homopolar motors. A later refinement is

the Barlow's Wheel. These were demonstration devices only, unsuited to practical

applications due to their primitive construction.

Fig III

Categori zation of electric motors

The classic division of electric motors has been that of Alternating Current (AC) types

vs. Direct Current (DC) types. This is more a de facto convention, rather than a rigid

distinction. For example, many classic DC motors run on AC power, these motors being

referred to as universal motors.

Rated output power is also used to categories motors, those of less than 746 Watts, for

example, are often referred to as fractional horsepower motors (FHP) in reference to the old

imperial measurement.

The ongoing trend toward electronic control further muddles the distinction, as modern

drivers have moved the commentator out of the motor shell. For this new breed of motor,

driver circuits are relied upon to generate sinusoidal AC drive currents, or some

approximation thereof. The two best examples are: the brushless DC motor and the stepping

motor, both being poly-phase AC motors requiring external electronic control, although


13/38

Monomobile

Page 13of 38

historically, stepping motors (such as for maritime and naval gyrocompass repeaters) were

driven from DC switched by contacts.

Considering all rotating (or linear) electric motors require synchronism between a moving

magnetic field and a moving current sheet for average torque production, there is a clearer

distinction between an asynchronous motor and synchronous types. An asynchronous motor

requires slip between the moving magnetic field and a winding set to induce current in the

winding set by mutual inductance; the most ubiquitous example being the common

AC induction motor which must slip to generate torque. In the synchronous types, induction

(or slip) is not a requisite for magnetic field or current production (e.g. permanent magnet

motors, synchronous brush-less wound-rotor doubly-fed electric machine).

Comparison of motor types

Servo motor

A servomechanism, or servo is an automatic device that uses error-sensing feedback to

correct the performance of a mechanism. The term correctly applies only to systems where

the feedback or error-correction signals help control mechanical position or other parameters.

For example, an automotive power window control is not a servomechanism, as there is no

automatic feedback which controls positionthe operator does this by observation. By

contrast the car's cruise control uses closed loop feedback, which classifies it as a

servomechanism.

Synchronous electric motor

A synchronous electric motor is an AC motor distinguished by a rotor spinning with coils

passing magnets at the same rate as the alternating current and resulting magnetic field which

drives it. Another way of saying this is that it has zero slip under usual operating conditions.

Contrast this with an induction motor, which must slip to produce torque. A synchronous

motor is like an induction motor except the rotor is excited by a DC field. Slip rings and

brushes are used to conduct current to rotor. The rotor poles connect to each other and move

at the same speed hence the name synchronous motor.

Induction motor

An induction motor (IM) is a type of asynchronous AC motor where power is supplied to the

rotating device by means of electromagnetic induction. Another commonly used name is


14/38

Monomobile

Page 14of 38

squirrel cage motor because the rotor bars with short circuit rings resemble a squirrel cage

(hamster wheel). An electric motor converts electrical power to mechanical power in its rotor

(rotating part). There are several ways to supply power to the rotor. In a DC motor this power

is supplied to the armature directly from a DC source, while in an induction motor this power

is induced in the rotating device. An induction motor is sometimes called a rotating

transformer because the stator (stationary part) is essentially the primary side of the

transformer and the rotor (rotating part) is the secondary side. Induction motors are widely

used, especially polyphone induction motors, which are often used in industrial drives.

Electrostatic motor (capacitor motor)

An electrostatic motor or capacitor motor is a type of electric motor based on the attraction

and repulsion of electric charge. Usually, electrostatic motors are the dual of conventional

coil-based motors. They typically require a high voltage power supply, although very small

motors employ lower voltages. Conventional electric motors instead employ magnetic

attraction and repulsion, and require high current at low voltages. In the 1750s, the first

electrostatic motors were developed by Benjamin Franklin and Andrew Gordon. Today the

electrostatic motor finds frequent use in micro-mechanical (MEMS) systems where their

drive voltages are below 100 volts, and where moving, charged plates are far easier to

fabricate than coils and iron cores. Also, the molecular machinery which runs living cells isoften based on linear and rotary electrostatic motors.

DC Motors

A DC motor is designed to run on DC electric power. Two examples of pure DC designs

are Michael Faraday's homopolar motor (which is uncommon), and the ball bearing motor,

which is (so far) a novelty. By far the most common DC motor types are the brushed and

brushless types, which use internal and external commutation respectively to create an

oscillating AC current from the DC sourceso they are not purely DC machines in a strict

sense.

Brushed DC motors

DC motor design generates an oscillating current in a wound rotor, or armature, with a split

ring commentator, and either a wound or permanent magnet stator. A rotor consists of one or

more coils of wire wound around a core on a shaft; an electrical power source is connected to

the rotor coil through the commentator and its brushes, causing current to flow in it,


15/38


16/38

Monomobile

Page 16of 38

Without a commutator to wear out, the life of a DC brushless motor can be significantly

longer compared to a DC motor using brushes and a commutator. Commutation also

tends to cause a great deal of electrical and RF noise; without a commutator or brushes, a

brushless motor may be used in electrically sensitive devices like audio equipment or

computers.

The same Hall effect sensors that provide the commutation can also provide a

convenient tachometer signal for closed-loop control (servo-controlled) applications. In

fans, the tachometer signal can be used to derive a "fan OK" signal.

The motor can be easily synchronized to an internal or external clock, leading to precise

speed control.

Brushless motors have no chance of sparking, unlike brushed motors, making them better

suited to environments with volatile chemicals and fuels. Also, sparking generates ozone

which can accumulate in poorly ventilated buildings risking harm to occupants' health.

Brushless motors are usually used in small equipment such as computers and are

generally used to get rid of unwanted heat.

They are also very quiet motors which is an advantage if being used in equipment that is

affected by vibrations.

Modern DC brushless motors range in power from a fraction of awattto many kilowatts.Larger brushless motors up to about 100 kW rating are used inelectric vehicles.They also

find significant use in high-performance electric model aircraft.

Coreless or ironless DC motors

Nothing in the design of any of the motors described above requires that the iron (steel)

portions of the rotor actually rotate; torque is exerted only on the windings of the

electromagnets. Taking advantage of this fact is the coreless or ironless DC motor, a

specialized form of a brush or brushless DC motor. Optimized for rapidacceleration,these

motors have a rotor that is constructed without any iron core. The rotor can take the form of a

winding-filled cylinder, or a self-supporting structure comprising only the magnet wire and

the bonding material. The rotor can fit inside thestatormagnets; a magnetically soft

stationary cylinder inside the rotor provides a return path for the stator magnetic flux. A

second arrangement has the rotor winding basket surrounding the stator magnets. In that

design, the rotor fits inside a magnetically soft cylinder that can serve as the housing for the

motor, and likewise provides a return path for the flux.
http://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Watthttp://en.wikipedia.org/wiki/Electric_vehiclehttp://en.wikipedia.org/wiki/Electric_vehiclehttp://en.wikipedia.org/wiki/Electric_vehiclehttp://en.wikipedia.org/wiki/Accelerationhttp://en.wikipedia.org/wiki/Accelerationhttp://en.wikipedia.org/wiki/Accelerationhttp://en.wikipedia.org/wiki/Statorhttp://en.wikipedia.org/wiki/Statorhttp://en.wikipedia.org/wiki/Statorhttp://en.wikipedia.org/wiki/Statorhttp://en.wikipedia.org/wiki/Accelerationhttp://en.wikipedia.org/wiki/Electric_vehiclehttp://en.wikipedia.org/wiki/Watt


17/38

Monomobile

Page 17of 38

Chapter 5: VOLTAGE REGULATERS

Regulator

Voltage regulator ICs are available with fixed

(typically 5, 12 and 15V) or variable output

voltages. They are also rated by the maximum

current they can pass. Negative voltage

regulators are available, mainly for use in dual

supplies. Most regulators include some

automatic protection from excessive current

('overload protection') and overheating

('thermal protection').

Many of the fixed voltage regulator ICs have

3 leads and look like power transistors, such as the 7805 +5V 1A regulator shown on the

right. They include a hole for attaching a heat sink if necessary.

Please see the Electronics in Meccano website for more information about voltage regulator

ICs.

Fig V: An assortment of 78XX ICs

Voltage regulator

Fig IV
http://wiki/File:7800_IC_regulatorsa.jpg


18/38


19/38

Monomobile

Page 19of 38

CHAPTER 6: MOTOR DRIVERS

L293D is a dual H-Bridge motor driver, so with one IC we can interface two DC motors

which can be controlled in both clockwise and counter clockwise direction and if you have

motor with fix direction of motion the you can make use of all the four I/Os to connect up to

four DC motors. L293D has output current of 600mA and peak output current of 1.2A per

channel. Moreover for protection of circuit from back EMF output diodes are included within

the IC. The output supply (VCC2) has a wide range from 4.5V to 36V, which has made

L293D a best choice for DC motor driver.

A simple schematic for interfacing a DC motor using L293D is shown below

Fig VI


20/38

Monomobile

Page 20of 38

As you can see in the circuit, three pins are needed for interfacing a DC motor (A, B, Enable).

If you want the o/p to be enabled completely then you can connect Enable to VCC and only 2

pins needed from controller to make the motor work.

As per the truth mentioned in the image above its fairly simple to program the

microcontroller. Itsalso clear from the truth table of BJT circuit and L293D the

programming will be same for both of them, just keeping in mind the allowed combinations

of A and B. We will discuss about programming in C as well as assembly for running motor

with the help of a microcontroller. As seen from above, l293d is an 16 pin IC(integrated

Circuit) shown below along with its pin configuration:

An H-bridgeis anelectronic circuit which enables a voltage to be applied across a load in either

direction. These circuits are often used inrobotics and other applications to allow DC motors to run

forwards and backwards. H-bridges are available asintegrated circuits,or can be built from discrete

components.

A "double pole double throw"relay can generally achieve the same electrical functionality as an H-

bridge (considering the usual function of the device). Though an H-bridge would be preferable where a

smaller physical size is needed, high speed switching, low driving voltage, or where the wearing out ofmechanical parts is undesirable.

The term "H-bridge" is derived from the typical graphical representation of such a circuit. An H-bridge

is built with four switches (solid-state or mechanical). When the switches S1 and S4 (according to the

first figure) are closed (and S2 and S3 are open) a positive voltage will be applied across the motor. By

opening S1 and S4 switches and closing S2 and S3 switches, this voltage is reversed, allowing reverse

operation of the motor.
http://en.wikipedia.org/wiki/Electronic_circuithttp://en.wikipedia.org/wiki/Roboticshttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Relayhttp://en.wikipedia.org/wiki/Relayhttp://en.wikipedia.org/wiki/Integrated_circuitshttp://en.wikipedia.org/wiki/Roboticshttp://en.wikipedia.org/wiki/Electronic_circuit


21/38

Monomobile

Page 21of 38

Using the nomenclature above, the switches S1 and S2 should never be closed at the same time, as this

would cause a short circuit on the input voltage source. The same applies to the switches S3 and S4.

This condition is known as shoot-through

Fig VII: H- Bridge

L293D PIN CONFIGURATION AND input- output logic function table:


22/38


23/38

Monomobile

Page 23of 38

transformer is also very important, as the leakage inductance should be minimized, or cross

conduction may occur. The outputs of the transformer also need to be usually clamped by

zener diodes, because high voltage spikes could destroy the MOSFET gates.

A common variation of this circuit uses just the two transistors on one side of the load,

similar to a class AB amplifier. Such a configuration is called a "half bridge". The half bridge

is used in some switched-mode power supplies that use synchronous rectifiers and in

switching amplifiers. The half H-bridge type is commonly abbreviated to "Half-H" to

distinguish it from full ("Full-H") H-bridges. Adding a third 'leg' to the bridge creates a 3-

phase inverter, the core of any AC motor drive.

A further variation is the half-controlled bridge, where one of the high- and low-side

switching devices (on opposite sides of the bridge) are replaced with diodes. This eliminates

the shoot-through failure mode, and is commonly used to drive variable/switched reluctance

machines and actuators where bi-directional current flow is not required.

One of the first realizations in robotics is that making something move isnt an easy task. You

simply cant take a brain circuit and connect it to a motor and expect anything to happen.

The motor will simply say HAH! at the puny output signal from the brains, and stay

stationary. What the brain needs is an enforcer muscle. Something to convince the motor todo things the way the brains want it to be done. There are many ways to strengthen (buffer)

a signal so its strong enough to drive a large load like a motor. Transistor H-bridges circuit,

buffer chips, and dedicated motor driving chips are all suitable candidates, with their own

benefits and limitations. For our Secret motor driver, we wanted something that would take

standard TTL (well, CMOS too) inputs and make a standard servo our slave. You see,

standard servos use a Pulse Width Modulated (PWM) signal to tell a servo where to

rotate to. PWM works by sending a rapid train of high/low signals to the servos regular

driver brains, and depending on how different the high signal is from the low signal, the servo

moves to the

according position. PWM is great if you dont want to rotate much more than 180, which is

fine for actuators, but not for driving wheels. With our Secret motordriver and a bit of

servo hacking, weregoing to lobotomize and turn a standard servo into something more

useful - a small, compact, powerful gear motor! Itll be something you can use very simple


24/38


25/38

Monomobile

Page 25of 38

CHAPTER 6: WIRELESS COMMUNICATION

Wirelesstelecommunications, is the transfer of information between two or more points that

are physically not connected. Distances can be short, as a few meters as in television remote

control; or long ranging from thousands to millions of kilometers for deep-space radio

communications. It encompasses various types of fixed, mobile, and portable two-way

radios, cellular telephones, personal digital assistants (PDAs), and wireless networking. Other

examples of wireless technologyinclude GPS units, Garage door openers or garage doors,

wireless computer mice, keyboards and Headset (telephone/computer), headphones, radioreceivers, satellite television, broadcast television and cordless telephones.

Wireless operationspermits services, such as long range communications, that are

impossible or impractical to implement with the use of wires. The term is commonly used in

the telecommunications industry to refer to telecommunications systems (e.g. radio

transmitters and receivers, remote controls, computer networks, network terminals, etc.)

which use some form of energy (e.g. radio frequency (RF),acoustic energy, etc.) to transfer

information without the use of wires. Information is transferred in this manner over bothshort and long distances.

OVERVIEW OF RF TECHNOLOGY

Radio frequency(RF) is a rate of oscillation in the range of about 3 kHz to 300 GHz, which

corresponds to the frequency of radio waves, and the alternating currents which carry radio

signals. RF usually refers to electrical rather than mechanical oscillations, although

mechanical RF systems do exist.

PROPERTIES OF RF CIRCUITS

Electric Currents that oscillate at radio frequencies have special properties not shared

by direct current or alternating current of lower frequencies. The energy in an RF current can

radiate off a conductor into space as electromagnetic waves (radio waves); this is the basis of

radio technology. RF current does not penetrate deeply into electrical conductors but flows

along their surfaces; this is known as the skin effect. For this reason, when the human body

comes in contact with high power RF currents it can cause superficial but serious burns


26/38

Monomobile

Page 26of 38

calledRF burns. RF current can easily ionize air, creating a conductive path through it. This

property is exploited by "high frequency" units used in electric arc welding, which use

currents at higher frequencies than power distribution uses. Another property is the ability to

appear to flow through paths that contain insulating material, like the dielectric insulator of a

capacitor. When conducted by an ordinary electric cable, RF current has a tendency to reflect

from discontinuities in the cable such as connectors and travel back down the cable toward

the source, causing a condition called standing waves, so RF current must be carried by

specialized types of cable called transmission line.

RADIO COMMUNICATION

In order to receive radio signals an antenna must be used. However, since the antenna will

pick up thousands of radio signals at a time, a radio tuner is necessary to tune into a

particular frequency (or frequency range). This is typically done via a resonator in its

simplest form, a circuit with a capacitor and an inductor forming a tuned circuit. The

resonator amplifies oscillations within a particular frequency band, while reducing

oscillations at other frequencies outside the band.


27/38

Monomobile

Page 27of 38

Transmitter Section:

Now, we would be using 4 data bits from the parallel port and give it to the encoder module of a RF

circuit. Wireless data transmission is the second part of our hardware. This would be done with the

help of RF modules available. RF module, as the name suggests, uses radio frequency to send signals.

These signals are transmitted at a particular frequency and a baud rate. A receiver can receive these

signals only if it is configured for that frequency. This RF modulecomprises of an RF

Transmitterand an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency

of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its

antenna. The transmission occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received by an

RF receiver operating at the same frequency as that of the transmitter. But, in order to transmit and

receive signals from these wireless modules of frequency 434MHz, an extra circuitry called encoders

and decoders are used at the transmitter and receiver side respectively. At transmitter section, we have

a PC > Parallel port > DB25 connector > 4 bit parallel data output.

FigIX : Transmitter Block Diagram (TX-2B)


28/38

Monomobile

Page 28of 38

RECEIVER SECTION

Now, at receiver section we would install a receiver module first to receive the data

transmitted from RF Transmitter. Then this data would be given out from the receiver module

in a serial format and then a decoder circuitry is used that decodes this data and convert it into

parallel form and gives a 4 bit data output. This function is just reciprocal of that of the

transmitter. This decoded 4 bit output would then be transmitted the robot motors would be

controlled with the help of decoded signal received at the output with the help of a motor

driver H-Bridge and hence robot at the remote location would be controlled with the help of

commands entered by a remote PC.

FIG X: RECEIVER BLOCK DIAGRAM

Description:

The TX-2B/RX-2B is a pair of CMOS LSIs designed for remote controlled helicopter

applications. The TX-2B/RX-2B has five control keys for controlling the motions of the

helicopter.


29/38

Monomobile

Page 29of 38

Features:

* Wide operating voltage range (VCC=1.5~5.0V)

* Low stand-by current

* Auto-power-off function for TX-2B

* Few external components are needed

Fig XI: Pin Configuration


30/38

Monomobile

Page 30of 38

CHAPTER 7: DIODES

Diodes allow electricity to flow in only one direction. The arrow of the circuit symbol shows

the direction in which the current can flow. Diodes are the electrical version of a valve and

early diodes were actually called valves.

SYMBOL:

Light emitting diodes: The light emitting diode or LED is one of the most popular

types of diode. When forward biased with current flowing through the junction, light

is produced. The diodes use component semiconductors, and can produce a variety of

colours, although the original colour was red.

Photodiode: When light strikes a PN junction it can create electrons and holes,

causing a current to flow. As a result it is possible to use semiconductors to detect

light. These types of diodes can also be used to generate electricity. For some

applications, PIN diodes work very well as photo detectors.


31/38

Monomobile

Page 31of 38

Schottky diodes: This type of diode has a lower forward voltage drop than ordinary

silicon PN junction diodes. At low currents the drop may be somewhere between

0.15and 0.4 volts as opposed to 0.6 volts for a silicon diode. To achieve this

performance they are constructed in a different way to normal diodes having a metal

to semiconductor contact. They are widely used as clamping diodes, and in RF

Varicap or varactor diodes: This type of diode is used in radio frequency (RF)

applications. The diode has a reverse bias placed upon it and in this way no current

flows across the junction. However the width of the depletion layer varies according

to the amount of bias placed on it. The diode can be thought of as two plates of a

capacitor, with the depletion layer between them. As the capacitance varies according


32/38

Monomobile

Page 32of 38

to the width of the depletion layer and this can be varied by changing the reverse bias

on the diode, it is possible to control the capacitance of the diode.

Zener diode: The zener diode is a very useful type of diode. It is run under reverse

bias and when a certain voltage is reached it breaks down. If the current is limited

through a resistor, it enables a stable voltage to be produced. This type of diode is

therefore widely used to provide a reference voltage in power supplies.


33/38

Monomobile

Page 33of 38

CHAPTER-8: CHAIN DRIVE

Chain driveis a way of transmitting mechanical power from one place to another. It is often

used to convey power to the wheels of a vehicle, particularly bicycles and motorcycles. It is

also used in a wide variety of machines besides vehicles.

Most often, the power is conveyed by a roller chain, known as the drive

chainor transmission chain, passing over a sprocket gear, with the teeth of the gear

meshing with the holes in the links of the chain. The gear is turned, and this pulls the chain

putting mechanical force into the system. Another type of drive chain is the Morse chain,

invented by the Morse Chain Company of Ithaca, New York, USA. This has inverted teeth.

Sometimes the power is output by simply rotating the chain, which can be used to lift or drag

objects. In other situations, a second gear is placed and the power is recovered by attaching

shafts or hubs to this gear. Though drive chains are often simple oval loops, they can also go

around corners by placing more than two gears along the chain; gears that do not put power

into the system or transmit it out are generally known as idler-wheels. By varying the

diameter of the input and output gears with respect to each other, the gear ratio can be altered,

so that, for example, the pedals of a bicycle can spin all the way around more than once for

every rotation of the gear that drives the wheels.

A chain-drive system uses one or more roller chains to transmit power from a differential to

the rear axle. This system allowed for a great deal of vertical axle movement (for example,

over bumps), and was simpler to design and build than a rigid driveshaft in a workable

suspension. Also, it had less unsprang weight at the rear wheels than the Hotchkiss drive,

which would have had the weight of the driveshaft and differential to carry as well. This

meant that the vehicle would have a smoother ride. The lighter unsprang mass would allow

the suspension to react to bumps more effectively


34/38

Monomobile

Page 34of 38

CHAIN DRIVE


35/38

Monomobile

Page 35of 38

CHAPTER-9 APPLICATIONS

One of the main reason behind designing this wheelchair is to help the persons who are

physically challenged and are not able to work independently. This kind of wheelchair

provide them with one of basic right of society i.e. Right to freedom. With this chair, at least

they can perform their basic daily routine independently. The tilt sensors that we use can be

used with any body part which is functional like hands, head etc. With proper development of

this project it can be made to do so many things

Future scope of the microcontroller ki t used in this project

Various future scope of this microcontroller kit are:-

1. This coding serves the purpose of explaining the student of technical institute and

college about serial communication and its interfacing with microcontroller.

2. Useful for embedded application and robotics project.

3. Helpful for beginner in field of embedded system and robotics.


36/38

Monomobile

Page 36of 38

Chapter 10 : Conclusion

After complete designing of our project, we have made number of experiment on it. As on

very first run of our project, the relays failed. The reason behind the failure was the wrong

choice of relays but we replaced it and finally the project ran successfully . We learned a lot

from the project as this was our first practical experience.

We found that this project was properly working and each peripheral interfaced is properly

working, and many operations on this project can be performed very easily without any

difficulty.


37/38

Monomobile

Page 37of 38

Appendix I: References

1. RobokitsWorld RF Modules(Tx + Rx Pair) 433 MHz ASK [RKI-1064] - The RX

ASK is an ASK Hybrid receiver module,Online, 15 August 2008

3. Wireless Made Simple - RF module, antenna and connector solutions offer easily

applied remote control functionality to your product, Online, 18 August 2008

4.

Datasheet search site, datasheets, Datasheet search site for Electronic Componentsand Semiconductors, integrated circuits, diodes and other semiconductors.

Online, 31 August 2008

5. How Stuff Worksexplains hundreds of subjects, from car engines to lock-picking toESP, using clear language and tons of illustrations Online, 11 October 2008

Books

1. Author:Bibin John(Advanced search in robotics) Publisher: PEARSON, Prentice

Hall, 1990

2. RS components, Catalog book, 2008
http://www.robokitsindia.com/http://www.robokitsindia.com/http://www.robokitsindia.com/http://linxtechnology.com/http://linxtechnology.com/http://linxtechnology.com/http://www.alldatasheet.com/http://www.alldatasheet.com/http://www.alldatasheet.com/http://www.howstuffworks.com/http://www.howstuffworks.com/http://www.howstuffworks.com/http://www.howstuffworks.com/http://www.alldatasheet.com/http://linxtechnology.com/http://www.robokitsindia.com/


38/38

Monomobile

Appendix II : List of Figures

S.No Name of Figure Pg. No

Fig I Block Diagram 4

Fig II Block Diagram 5

FigIII Motor 9

Fig IV Voltage Regulator 14

Fig V 78XX ICs 14

Fig VI Motor Driver 16

Fig VII H-Bridge 18

Fig VIII H-Bridge 19

Fig IX Transmitter Block Diagram 24

Fig X Receiver Block Diagram 25

Fig XI Pin Configuration 26

Fig XII Diode 27

monomobile project file

Documents