Download - Car Light Control-final
-
7/27/2019 Car Light Control-final
1/65
SETH JAI PARKASH MUKAND LAL
INSTITUTE OF TECHNOLOGY, RADAUR
TO WARDS PRATIAL FULLFILLMENT OF THE REQUIREMENT
OF KURUKSHETRA UNIVERSITY
FOR BECHLOR OF TECHNOLOGY
IN MECNICAL ENGINEERING
PROJECT ON
CAR STEERING OPRATEDFRONT LIGHT
PREPARED AND SUBMITTED BY
SANJEEV K.PRABHAKAR ROLL NO.212154
SUNIL KUMAR ROLL NO.212152
RAJESHWAR ROLL NO.212159
SUBMITTED TO :-
MS. MAMTA JAIN MR. V.K. VERMA(PROJECT INCHARGE) H.O.D. (MECH.-ENGG.)
DEPARTMENT OF MECHANICAL ENGINEERING
RADAUR
-
7/27/2019 Car Light Control-final
2/65
CertificateCertified that the Project entitledCAR STEERING
OPRATED FRONT LIGHT is prepared and submitted by
This is the record of the work carried out by the group
Under our supervision and guidance.
This is further certified that, they have worked with zeal for the
complete semester for preparing this project.
-
7/27/2019 Car Light Control-final
3/65
Acknowledgement
After completing our projectCAR STEERING OPRATED
FRONT LIGHT, We wish to express my obligations to thecollege staff. We wish to express our obligations to our fellow
project markers.
We would like to thank and pay our obligations
(H.O.D.-Mech. Engg.) for his guidance
regarding the project. We would like to pay our special gratitude
to (Project Incharge) for her every ready helps.
We are also grateful to our family and friends for tolerating our
infrequent appearances over the period of realizing this project.
ForCAR STEERING OPRATED FRONT LIGHT
-
7/27/2019 Car Light Control-final
4/65
Foreword
The present project on CAR STEERING OPRATED FRONT
LIGHTis yet another contribution by Mr. Sanjeev K.Prabhakar (RollNo.212154), Mr. Sunil Kumar (Roll No.212152), Mr. Rajeshwar (Roll
No.212159), Mr.Suresh Kumar (Roll No.212161) Praveen Kumar Roll
(No.212156) and Mr. Pradeep Kumar (Roll No.212182), students 7th
sem. G.B.P.P. Okhla, in their efforts to develop basic informative and
instructive material for analysis and design ofCAR STEERING
OPRATED FRONT LIGHT. This report has been written as apart of the program of minor project as recommended by Borad ofTechnical Education Delhi as a part of curriculum in the starting of
7th semester of m...
Writing a report on technical aspect is indeed a very challenging task.
The student has to possess not only expertise in the subject matter but
also the technique of selecting appropriate material from the vast fund
of knowledge they have to have regarding the subject of project and
present it in a way which the readers can easily understand. Judgingfrom the remarks of the experts who reviewed the report and also on
the basis of earlier projects by these students in the Mechanical field. I
have no doubt in my mind that they had done an excellent job.
The institute will, therefore fell amply rewarded if the other students
and teachers may go through this report for enlarging their know how
ofCAR STEERING OPRATED FRONT LIGHT. Anysuggestions for the improvement of this project and the report from all
quarters will be most welcome.
-
7/27/2019 Car Light Control-final
5/65
Contents
1. CERTIFICATE..........................................................................6
2. COMPONENTS USED.................7
3. ACKNOWLEDGEMENT.................................................8
4. FOREWORD..............................................................9
5. INTRODUCTIONS......................................................9
6. METHODOLOGIES.............................................10
7. HOW OUR MODEL WORKS........................................16
8. APPROXIMATE COST...........................................................19
9. CONCLUSIONS..................................................23
10. APPLICATIONS.........................................25
11. USES.............................................................25
12. WORKING COMPONENTS DETAIL....................................26
-
7/27/2019 Car Light Control-final
6/65
5. INTRODUCTIONS
A FRONT LAMP STEERING CONTROLLED LIGHT DISTRIBUTION
SYSTEM IS DISCLOSED HAVING A LIGHT DISTRIBUTION MEANS
MOVABLE TO VARY A LIGHT DISTRIBUTION PATTERN TO RIGHT
AND LEFT MAXIMUM LIMIT POSITIONS IN CORNERING AREAS
OF A VEHICLE, AND A CONTROL MEANS RESPONSIVE TO A
TURNED ON STATE OF A HEAD LAMP SWITCH FOR ACTUATINGTHE LIGHT DISTRIBUTION MEANS TO CAUSE THE LIGHT
DISTRIBUTION PATTERN TO BE VARIED ACCORDING TO A
STEERING DIRECTION.
-
7/27/2019 Car Light Control-final
7/65
6. METHODOLOGIES
WE ARE CONSTRUCTING AN IRON FRAME APPROX. SIZE 2X3
FEETS. IN WHICH WE ARE FIXING TWO WHEELS AS FIX IN OURVEHICLES AND THEN WE ADJOINS THOSE WHEEL WITH THE
HELP OF TIE RODE AND THEN TIE RODE IS CONNECTED WITH
STEERING RODE AS MENTION BELOW DIAGRAM.
-
7/27/2019 Car Light Control-final
8/65
NOW WE ARE FIXING TWO DC MOTOR ATTECH WITH FRONT
LIGHT IN THE FRONT OF OUR FRAME AND MAKE THEM MOVING
WITH THE HELP OF MICROCHIP AND READ SWITCHS ATTECH
STEERING AND FRONT LIGHT DC MOTOR.
WE ARE ALSO USING SMALL ELECTRONIC MICROCHIP CIRCUIT
TO MAKE THIS MECHANICAL STRUCTURE AUTOMATED
WORKING.
-
7/27/2019 Car Light Control-final
9/65
7. HOW OUR MODEL WORKS
IN THIS PROJECT WE HAVE FIVE DIFFERENT MOVING POSITION
OF THE FRONT LIGHT AS SHOWN BELOW.
1. POSITION 2-RIGHT
2. POSITION 1-RIGHT
3. POSITION 0-CENTRE
4. POSITION 1-LEFT
5. POSITION 2-LEFT
-
7/27/2019 Car Light Control-final
10/65
WE ARE USING IR INTREPUTERSENSOR TO IDENTIFY THE
CURRENT POSITON OF FRONT LIGHT. THESE IR INTREPUTE
PROVIED PULSE TO THE MICROCHIP CIRCUIT AND MICROCHIP
CONTROL FRONT LIGHT FIXED DC MOTOR.
HOW IR INTREPUTER SENSOR WORKS
THESE IR INTREPUTERSENSOR WORK WHEN SOME
OBSTRUCTION CUT TRANSMITTER (TX) AND RECEIVER (RX)
SEE HOW IT WORKS
TX AND RX TRANSMITTING WAVE IN BETWEEN EACH OTHER
OBSTRUCTION CUT TO THE WAVE AND SENSOR GENRERATE
PULSE
-
7/27/2019 Car Light Control-final
11/65
IR INTREPUTER SENSOR
NOW WE ARE USING THESE IR INTREPUTER SENSORIN OUR
MODEL TO MAKE MOVMENT AND IDENTIFED LIGHT POSITION,
-
7/27/2019 Car Light Control-final
12/65
IR INTREPUTER SENSOR PLACEMENT
HOW THESE SENSOR PLACED IN
BETWEEN STEERING AND TIE
RODE
-
7/27/2019 Car Light Control-final
13/65
WHEN STEERING MOVE, IT GIVE MOVEMENT TO TIE RODE.
WE FIX ONE INTRUPTER BAR WITH TIE RODE WHEEL.
WHEN WHEEL MOVES IT MOVE TO INTRUPTER BAR AND
INTRUPTER BAR SHOT TO IR INTREPUTER SENSORAS
MENTION ABOVE.
IR INTREPUTER SENSORGIVE PULSE TO THE ELECTRONIC
CIRCUIT AND CIRCUIT DRIVE THE FRONT LIGHT
AS MENTION BELOW
-
7/27/2019 Car Light Control-final
14/65
FRONT LIGHT MOVEMENT
-
7/27/2019 Car Light Control-final
15/65
APPROXIMATE COST
RS. 20000/-
CONCLUSIONSTHIS CAN BE VERY USEFUL SYSTEM IN OUR CAR WHEN WE ARE
CUTTING TO THE CAR RIGHT/LIFT FOR MORE FRONT CLEAR
VISIBLITY.
APPLICATIONSTHIS COULD BE IMPLEMENT IN OUR VECHICAL ESPICHIALLY IN
HEAVY CHEMIRCAL VECHIAL (TRUCK AND BUSES)
-
7/27/2019 Car Light Control-final
16/65
USESIT PROVIDE LIGHT TO THE VECHIAL IN SHORT
TURNNING AND PROTECT FROM ACCIDENT
COMPONENTS USED1. STEERING
2. TIE RODE
3. TYRES
4. LIGHT
5. TWO MOTOR FOR MOVEMENT OF LIGHT
6. MODEL FRAME
7. SOME ELECTRONIC COMPONENTS AS PER REQUIRMENT RELAY
IR INTREPUTER SENSOR
MICROCHIP (AT89S52)
TRANSISTOR
CAPISITOR
RESISTANCE
DIODE
TRANSFORMER
-
7/27/2019 Car Light Control-final
17/65
COMPONENT DETAIL
1.STEERING AND SUSPENSION
1. Tie Rod - Right
2. Tie Rod Socket - Right
3. Knuckle and Arm - Right
4. Steering Bell Crank
5. Steering Connecting Rod
6. Steering Gear Arm
7. Steering Gear Arm Assembly
8. Knuckle and Arm - Left
9. Tie Rod Socket - Left
-
7/27/2019 Car Light Control-final
18/65
10.Tie Rod - Left
11.Socket Assembly
12.Steering Bell Crank Pin
13.Steering Bell Crank Cotter Pin
14.Steering Bell Crank Shaft
STEERING SYSTEMThe Steering System is illustrated in Fig. 30. It requires little attention
other than proper lubrication and maintaining correct alignment.
Alignment may be thrown out by striking curbs or other obstructions.
Looseness in the steering system will also affect alignment. It is impossible
to satisfactorily align front wheel without first adjusting the various
connections, including the front wheel bearings.
The correct toe-in of the front wheels is 3/64 3/32 which must be
accurately measured for satisfactory front tire wear and steering. The best
method of checking wheel alignment is by the use of the wheel alignmentdevice, which is available in most every well equipped shop.
-
7/27/2019 Car Light Control-final
19/65
Periodic inspection and tightening of the steering parts will aid greatly in
maintaining alignment. Keep the steering connection rod and tie rod ball
joints snug; they must operate freely without lost motion. Keep the steering
gear arm No. 6 tight on the lever shaft and the steering housing bracket tight
on the frame. For adjustment of the front wheel bearings see the next
section, Front Wheel Bearings
1.
Housing Oil Seal
2. Lever Shaft Assembly
3. Housing Oil Filler Plug
4. Steering Column Clamp Assembly
5. Cam & Wheel Tube Assembly
6. Steering Column Oil Hole Cover
7. Horn Wire Contact Brush Assembly8. Steering Wheel
9. Steering Column Bearing Spring
10. Steering Column Bearing Spring Set
11. Steering Column Bearing Assembly
-
7/27/2019 Car Light Control-final
20/65
2. 12. Steering Column & Bearing Assembly
13. Steering Wheel & Horn Button Nut
14. Horn Button
15. Horn Button Spring
16. Horn Button Spring Cup
17. Side Adjusting Screw
18. Housing Assembly
19. Cam Bearing Balls
20. Steering Gear Arm
21. Housing Bushing - Inner
22. Housing Bushing - Outer
The bell crank No. 4 is mounted on the frame front cross tube and swivels
on two needle bearings. The mounting shaft is removable from the frame
bracket by driving out a tapered locking pin. The bell crank tie-rod ball isreplaceable. Should the bell crank become bent or damaged, install a new
part.
Do not tighten the steering gear to dampen out steering trouble. Should
trouble develop, consult your Willys-Overland Dealer, as he has a definite
procedure for the inspection
and adjustment of the steering system.
FRONT WHEEL BEARINGSThe front wheels are mounted on two opposed tapered roll bearings. These
bearings are adjustable for wear and their satisfactory operation and long life
depends upon periodic attention and correct lubrication. Loose front wheel
bearings may cause excessive wear and will affect front wheel alignment. Ifthe bearing adjustment is too tight, the rollers may break or become
overheated.
To check the adjustment, first raise the front of the vehicle so that the tires
clear the floor. Check the brakes to be sure they are free and fully released.
With the hands, check sidewise shake of the wheel. If the bearings are
-
7/27/2019 Car Light Control-final
21/65
correctly adjusted, shake of the wheel will be just perceptible and the wheel
will turn freely with no drag.
Should the test indicate that adjustment is necessary, remove the hub cap
axle shaft nut, washer, driving flange and shims. See Fig. 25. Wheel
bearing adjustment will then be accessible. Bend the lip of the nut locking
washer so that the adjustment lock nut and washer can be removed. Rotate
the wheel and tighten the adjusting nut until the wheel binds slightly. Then
back off the nut 1/6 turn, or more if necessary, making sure the wheel turns
freely without sidewise shake. Replace the locking washer and lock nut and
bend over the locking washer lip. Check the adjustment and reassemble the
driving flange, nut and hub cap, being sure to replace the shims.
REAR WHEEL BEARINGS
Each rear wheel is carried on a single tapered roller bearing which isadjusted by shims placed between the brake backing plate and the axle
flange.
Check wheel bearing adjustment in the same manner as the front wheel.
Should the check determine that adjustment is required, remove the hub cap;
remove the cotter pin, the axle shaft nut and use a wheel puller to remove the
wheel hub. Remove the bolts holding the brake dust shield, the grease and
bearing retainer and the brake assembly. Remove or install shims, Fig. 32,
No. 2 to adjust the bearing with .001" to .003" end float which will be just
perceptible when tested by hand. The shims available for this adjustment are
.003" - .005" and .030" thick.
Examine the grease retainer to be sure it is serviceable -- replace it if in
doubt, and reassemble.
MAINTENANCE OF WHEEL
BEARINGSWhen the vehicle is used for road work, lubricate
and adjust the front wheel bearings once each year;if used in dusty field work, twice each year.
The bearings should be given more than casual
cleaning. Use a clean stiff brush and suitable grease
solvent to remove all particles of old lubricant from
the bearings and hubs. After the bearings are
-
7/27/2019 Car Light Control-final
22/65
thoroughly cleaned, inspect them for pitted races and rollers and check the
hub oil seals.
Repack the bearing cones and rollers and reassemble in the reverse order of
dismantling. Adjust them as directed in the preceding paragraphs.
Lubricate the rear wheel bearings sparingly. Oil forced from the oil relief
hole No. 1, Fig. 32, indicates when the bearing is amply lubricated.
Should it be necessary to adjust the bearings, clean them thoroughly and
repack them with the recommended lubricant.
MOUNTING AND DISMOUNTING WHEELSThe wheel mounting nuts and studs on both left wheels have left hand
threads to prevent them from being loosened by wheel action. The studs are
identified by an "L" stamped on the end. The left hand threaded nuts are
identified by a groove cut around the hexagonal faces. To remove the left
wheels, the nuts must be turned RIGHT, and to remove the right wheels,
turned to the LEFT.
TIRESThe recommended tire pressures are as follows:
6:00 x 16 Tires7:00 x 15 Tires
28-30 lbs.20-21 lbs.
The importance of correct tire inflation cannot be overemphasized. To
secure the maximum tire life and most efficient vehicle operation, it is
imperative that these pressures be maintained for all normal vehicle
operations.
Then the vehicle is used with driver only doing agricultural work on very
sandy or muddy soil, increased flotation and wheel traction may be secured
by decreasing the pressure of the 6:00 x 16 tire to 18 to 20 lbs., and the 7:00
-
7/27/2019 Car Light Control-final
23/65
x 15 tire to 14 lbs. Should unusual operating conditions require this
reduction in pressure, use care that the tires are inflated to the recommended
pressure immediately when normal operation is resumed.
To secure maximum tire wear, the wheels should be switched at least twice
each year. The rear wheels should be moved to the opposite front positions
and the right front wheel moved straight back to the right rear position.
Place the spare on the left rear and use the left front as a spare.
To remove a tire from a drop centre rim, first deflate completely and then
force the tire away from the rim throughout the entire circumference until
the bead falls into the centre of the wheel rim, then with a heavy screw
driver or tire removing tool, used opposite the valve, remove one side of the
tire at a time and remove the inner tube.
Installation of a tire is made in the same manner by first dropping one side of
the tire into the centre of the rim and with a tire tool, spring the bead over
the wheel rim, using care not to damage the inner tube.
When mounting the wheel, alternately tighten opposite stud nuts to prevent
wheel wobble. After nuts have been tightened with the wheel jacked up,
lower the jack so wheel rests on the floor and retighten the nuts.
SPRINGS AND SHACKLESThe springs should be periodically examined for broken or shifted leaves,loose or missing rebound clips, angle of the spring shackles and the position
of the springs on the axle saddles. Springs with shifted leaves to not have
their normal strength. Missing rebound clips may permit the leaves to fan
out or break on rebound. Broken leaves may make the vehicle hard to
handle or permit the axle to shift out of line. Weakened springs may break
causing difficulty steering.
The front springs are interchangeable, as are the two rear.
The front ends of the front springs and the rear ends of the rear springs are
shackled, using "U" type shackles with threaded bushings. The rear ends of
the front springs and the front ends of the rear springs are bronze bushed and
pivoted on bolts in the shackles mounted on the frame.
The spring shackle threaded bushings use right and left hand threads,
depending upon where they are to be used. Six bushings are used with right
-
7/27/2019 Car Light Control-final
24/65
hand threads and two with left hand threads. For identification the right
hand threaded type have plain hexagonal heads. The left hand have a groove
cut around the heads.
The two left hand threaded shackles can be identified by a small forged boss
on the lower shank of the shackle. They are used at the left front and the
right rear springs with the left hand threaded end down at the spring eyes.
The bushings are anchored solidly in the frame brackets and spring eyes and
the oscillation taken between the threads of the "U" shackle and the inner
threads of the bushings. The lubrication of the shackle bushings is very
important and should not be neglected, or excessive wear of the bushings
and "U" shackles will occur.
When making installation of a new "U" shackle or bushing, follow theprocedure below:
The shackles are installed with the bushing hexagon heads to the outside of
the frame. Install the shackle grease seal and retainer over the threaded end
of the shackle up to the shoulder. Insert the new shackle through the frame
bracket and the eye of the spring. Hold the "U" shackle tightly against the
frame bracket and start the upper bushing on the shackle, care being taken
when it enters the thread in the frame, that it is not cross-threaded. Screw
the bushings on the shackle about halfway, and then start the lower bushing,
hold the shackle tightly against the spring eye and thread this bushing abouthalfway, then alternating from top bushing to lower bushing, turn them in
until the head of the bushing is snug against the frame bracket and the
bushing in the spring eye is 1/32" away from the spring measured from the
inside of the hexagon head to the spring.
Lubricate the bushings with high pressure lubricant and then try the flex of
the shackle, which should be free. If the shackle is tight, it will cause spring
breakage and it will be necessary to rethread the bushings on the shackle.
SHOCK ABSORBERSThe shock absorbers are of the direct action type giving two-way control,
however they are not adjustable. They dampen spring action, as the vehicle
passes over irregularities in the road. The shock absorbers are mounted on
rubber bushings at both top and bottom. Should squeaks occur in the
-
7/27/2019 Car Light Control-final
25/65
bushings, add a flat washer on the mounting pins to place the bushings under
greater pressure and prevent movement between the rubber and metal parts.
2. IR INTREPUTER SENSOR
PCB or Chassis Mount Photo Interrupter
This device enables you to turn off a circuit on and off optically. It consists
of an IR LED facing a phototransistor across and air gap. Any object in the
gap will interrupt the IR beam and consequently switch the phototransistor
on and off. The device is very fast and ideal for counting, timing or sensing
Block Measures 25Lx5Wx13H
Gap measure 3mm
Mounting Holes 3.2mm Dia
-
7/27/2019 Car Light Control-final
26/65
Dc
motor
-
7/27/2019 Car Light Control-final
27/65
DC GEAR MOTOR
Brand HOSIDEN motors (Japan)
R.P.M: 75-100
VOLT: 12-18V. DC
Dc motorMost electric motors work by electromagnetism, but motors based
on other electromechanical phenomena, such as electrostatic forcesand thepiezoelectric effect, also exist. The fundamental principle
upon which electromagnetic motors are based is that there is a
mechanical force on any current-carrying wire contained within a
magnetic field. The force is described by the Lorentz force law and
is perpendicular to both the wire and the magnetic field. Most
magnetic motors are rotary, but linear motors also exist. In a rotary
motor, the rotating part (usually on the inside) is called the rotor,
and the stationary part is called the stator. The rotor rotates becausethe wires and magnetic field are arranged so that a torque is
developed about the rotor's axis. The motor contains
electromagnets that are wound on a frame. Though this frame is
often called the armature, that term is often erroneously applied.
Correctly, the armature is that part of the motor across which the
http://en.wikipedia.org/wiki/Magnetismhttp://en.wikipedia.org/wiki/Electrostatic_motorhttp://en.wikipedia.org/wiki/Piezoelectric_effecthttp://en.wikipedia.org/wiki/Lorenz_forcehttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Linear_motorhttp://en.wikipedia.org/wiki/Rotorhttp://en.wikipedia.org/wiki/Statorhttp://en.wikipedia.org/wiki/Torquehttp://en.wikipedia.org/wiki/Electromagnethttp://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Magnetismhttp://en.wikipedia.org/wiki/Electrostatic_motorhttp://en.wikipedia.org/wiki/Piezoelectric_effecthttp://en.wikipedia.org/wiki/Lorenz_forcehttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Linear_motorhttp://en.wikipedia.org/wiki/Rotorhttp://en.wikipedia.org/wiki/Statorhttp://en.wikipedia.org/wiki/Torquehttp://en.wikipedia.org/wiki/Electromagnethttp://en.wikipedia.org/wiki/Armature_(electrical_engineering) -
7/27/2019 Car Light Control-final
28/65
input voltage is supplied. Depending upon the design of the
machine, either the rotor or the stator can serve as the armature.
One of the first electromagnetic rotary motors was invented by
Michael Faraday in 1821 and consisted of a free-hanging wire
dipping into a pool ofmercury. A permanent magnet was placed in
the middle of the pool of mercury. When a current was passed
through the wire, the wire rotated around the magnet, showing that
the current gave rise to a 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 electric motors called
homopolar motors. A later refinement is the Barlow's Wheel.
Another early electric motor design used a reciprocating plunger
inside a switched solenoid; conceptually it could be viewed as an
electromagnetic version of a two stroke internal combustion
engine.
The modern DC motor was invented by accident in 1873, whenZnobe Gramme connected a spinning dynamo to a second similar
unit, driving it as a motor.
The classic DC motor has a rotating armature in the form of an
electromagnet. A rotary switch called a commutatorreverses the
direction of the electric current twice every cycle, to flow through
the armature so that the poles of the electromagnet push and pull
against the permanent magnets on the outside of the motor. As the
poles of the armature electromagnet pass the poles of thepermanent magnets, the commutator reverses the polarity of the
armature electromagnet. During that instant of switching polarity,
inertia keeps the classical motor going in the proper direction. (See
the diagrams below.)
http://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Michael_Faradayhttp://en.wikipedia.org/wiki/1821http://en.wikipedia.org/wiki/Mercury_(element)http://en.wikipedia.org/wiki/Magnethttp://en.wikipedia.org/wiki/Current_(electricity)http://en.wikipedia.org/wiki/Brinehttp://en.wikipedia.org/wiki/Homopolar_motorhttp://en.wikipedia.org/wiki/Barlow's_Wheelhttp://en.wikipedia.org/wiki/Solenoidhttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Z%C3%A9nobe_Grammehttp://en.wikipedia.org/wiki/Dynamohttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Inertiahttp://en.wikipedia.org/wiki/Voltagehttp://en.wikipedia.org/wiki/Michael_Faradayhttp://en.wikipedia.org/wiki/1821http://en.wikipedia.org/wiki/Mercury_(element)http://en.wikipedia.org/wiki/Magnethttp://en.wikipedia.org/wiki/Current_(electricity)http://en.wikipedia.org/wiki/Brinehttp://en.wikipedia.org/wiki/Homopolar_motorhttp://en.wikipedia.org/wiki/Barlow's_Wheelhttp://en.wikipedia.org/wiki/Solenoidhttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Internal_combustion_enginehttp://en.wikipedia.org/wiki/Z%C3%A9nobe_Grammehttp://en.wikipedia.org/wiki/Dynamohttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Commutator_(electric)http://en.wikipedia.org/wiki/Armature_(electrical_engineering)http://en.wikipedia.org/wiki/Inertia -
7/27/2019 Car Light Control-final
29/65
A simple DC electric motor. When the coil is powered, a magnetic
field is generated around the armature. The left side of the
armature is pushed away from the left magnet and drawn toward
the right, causing rotation.
The armature continues to rotate.
When the armature becomes horizontally aligned, the commutator
reverses the direction of current through the coil, reversing the
magnetic field. The process then repeats.
http://en.wikipedia.org/wiki/Image:Electric_motor_cycle_1.png -
7/27/2019 Car Light Control-final
30/65
ELECTRONIC COMPONENTS DETAIL
MICROCHIP - CONTROLLING IC AT89S52
INTRODUCTION
Security is the main problem of the homes, buildings, offices and industry
now days.
Hence we develop here an intelligent building system that monitor
continuously the parameters in different rooms in a building or differentapartment in industry and also control the problems arises in different
places.
The parameters the voltage and current signals by produced by sensors.
The signals are generated by temp. and light .controlling the devices if any
one the conditions of analog parameter exceed the limit.
BRIEF IDEA OF THE WORKING:
When there is dark in room 1 the lights will switched on. And if the lightintensity in the room crosses the higher limit then the lights switched of
accordingly. When the temp. of the room is less then 30c then the 1st AC will
switched on and if the temp. does not goes down
Then the second AC will also switch on but if the temp. goes down and
becomes less then 20c then the AC will off. The status of the temp. and
lights are monitor continuously and the switching of the AC and lights are
-
7/27/2019 Car Light Control-final
31/65
according to it. The same function is applied on the second room. The temp.
of both rooms are displayed on the seven segment displays.
SCOPE OF THE PROJECT
This project can be the beneficial factor in the development of the buildings.
This application gives the basic idea in the architecture of the buildings like
what features should be their in a building for the safety of human life,
saving the energy and money.
As its name shows the can be used in the following:-
Houses
Companies
Factories
Schools and Colleges
-
7/27/2019 Car Light Control-final
32/65
PREVIOUS WORK
The following steps I have taken to complete the project:.1. Complete study of the c 8051 and understand the programming
based on it.
2. Prepare the block diagram and the ckt. Diagram of the project and
clear up the working of the project .
3. Collect all the component and made-up the hardware model of it.
4. Write the software of it.
5. Test the hardware and software in different modes.
-
7/27/2019 Car Light Control-final
33/65
A BRIEF INTRODUCTION TO
MICROCONTROLLER
Microcontrollers, as the name suggests, are small controllers. They are like
single chip computers that are often embedded into other systems to function
as processing/controlling unit. For example, the remote control you are using
probably has microcontrollers inside that do decoding and other controlling
functions. They are also used in automobiles, washing machines, microwave
ovens, toys ... etc, where automation is needed.
KEY FEATURES OF MICROCONTROLLERS:
HIGH INTEGRATION OF FUNCTIONALITY
Microcontrollers sometimes are called single-chip computers because they
have on-chip memory and I/O circuitry and other circuitries that enable them
to function as small standalone computers without other supporting circuitry.
FIELD PROGRAMMABILITY, FLEXIBILITY
Microcontrollers often use EEPROM or EPROM as their storage device toallow field programmability so they are flexible to use. Once the program is
tested to be correct then large quantities of microcontrollers can be
programmed to be used in embedded systems.
-
7/27/2019 Car Light Control-final
34/65
EASY TO USE
Assembly language is often used in microcontrollers and since they usually
follow RISC architecture, the instruction set is small. The developmentpackage of microcontrollers often includes an assembler, a simulator, a
programmer to "burn" the chip and a demonstration board. Some packages
include a high-level language compiler such as a C compiler and more
sophisticated libraries.
-
7/27/2019 Car Light Control-final
35/65
MICROCONTROLLER (AT89C51)
8051 microcontroller has 128 bytes of RAM, 4K bytes of on-chip ROM, twotimers, one serial port, and four ports (each 8-bits wide) all on a single chip.
The 8051 is an 8-bit processor i.e. the CPU can work on only 8 bits of data
at a time. The fixed amount of on-chip ROM, RAM, and number of I/O
ports in microcontroller makes them ideal for many applications in which
cost and space are critical.
The AT89C51 is a low-power, high-performance CMOS 8-bit
microcomputer with 4K bytes of Flash programmable and erasable read only
memory (PEROM). The on-chip Flash allows the program memory to bereprogrammed in-system or by a conventional nonvolatile memory
programmer. By combining a versatile 8-bit CPU with Flash on a monolithic
chip, the Atmel AT89C51 is a powerful microcomputer, which provides a
highly flexible and cost-effective solution to many embedded control
applications.
FEATURES:
Compatible with MCS-51 Products
4K Bytes of In-System Reprogrammable Flash Memory
Endurance: 1,000 Write/Erase Cycles
Fully Static Operation: 0 Hz to 24 MHz
Three-level Program Memory Lock
128 x 8-bit Internal RAM
32 Programmable I/O Lines
Two 16-bit Timer/Counters
-
7/27/2019 Car Light Control-final
36/65
Six Interrupt Sources
Programmable Serial Channel
Low-power Idle and Power-down Modes
BLOCK DIAGRAM:
Int
err
up
t
contr
ol
Bu
sco
ntr
ol
Se
rial
p
or
E
T
C.Osc
C
P
U 4
I/O
Po
rts
On
-chi
p
RA
M
O
n-
chip
R
OM
fo
Timer 0
Timer 1
CounterIn
puts
P0 P1 P2 P3 TXD RXD
ADDRESS/DATA
External
Interrupt
s
-
7/27/2019 Car Light Control-final
37/65
PIN CONFIGURATION:
PIN DESCRIPTION:
tpr
og
ram
co
de
1 40
2 39
3 38
4 37
5 36
6 35
7 34
8 33
9 32
10 31
11 30
12 29
13 28
14 27
15 26
16 25
17 24
18 23
19 22
20 21
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
RST
(RXD) P3.0
(TXD) P3.1
(INT0) P3.2
(INT1) P3.3
(T0) P3.4
(T1) P3.5
(WR) P3.6
(RD) P3.7
XTAL2
XTAL1
GND
Vcc
P0.0 (AD0)
P0.1 (AD1)
P0.2 (AD2)
P0.3 (AD3)
P0.4 (AD4)
P0.5 (AD5)
P0.6 (AD6)
P0.7 (AD7)
EA/VPP
ALE/PROG
PSEN
P2.7 (A15)
P2.6 (A14)
P2.5 (A13)
P2.4 (A12)
P2.3 (A11)
P2.2 (A10)
P2.1 (A9)
P2.0 (A8)
-
7/27/2019 Car Light Control-final
38/65
PIN DESCRIPSION:
VCC - Supply voltage.
GND - Ground.
Port 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 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 lowwill source current (IIL) because of the internal pull-ups. Port 1 also receives
the low-order address bytes during Flash programming and verification.
Port 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 use 16-bit addresses (MOVX @ DPTR). In this application, it uses strong internal
pull-ups when emitting 1s. During accesses to external data memory that use
8-bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special
Function Register.
-
7/27/2019 Car Light Control-final
39/65
Port 2 also receives the high-order address bits and some control signals
during Flash programming and verification.
Port 3 - Port 3 is an 8-bit bi-directional I/O port with internal pullups.
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 pullups and can be
used as inputs. As inputs, Port 3 pins that are externally being pulled low
will source current (IIL) because of the pullups. Port 3 also serves the
functions of various special features of the AT89C51 as listed below:
RST - Reset input. A high on this pin for two machine cycles while the
oscillator is running resets the device.
ALE/PROG - Address Latch Enable output pulse for latching the low byte
of the address during accesses to external memory. This pin is also theprogram pulse input (PROG) during Flash programming.
PORT PIN ALTERNATE FUNCTIONS
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)
-
7/27/2019 Car Light Control-final
40/65
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.
PSEN - Program Store Enable is the read strobe to external program
memory. When the AT89C51 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 - 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.
XTAL1 - Input to the inverting oscillator amplifier and input to the internal
clock operating circuit.
XTAL2 - Output from the inverting oscillator amplifier.
-
7/27/2019 Car Light Control-final
41/65
OSCILLATOR CHARACTERISTICS:
XTAL1 and XTAL2 are the input and output, respectively, of an inverting
amplifier, which can be configured for use as an on-chip oscillator. Either aquartz crystal or ceramic resonator may be used. To drive the device from an
external clock source, XTAL2 should be left unconnected while XTAL1 is
driven.
Figure 1. Oscillator Connections
Note: C1, C2 = 30 pF +/- 10 pF for Crystals
= 40 pF +/- 10 pF for Ceramic Resonators
There are no requirements on the duty cycle of the external clock signal,
since the input to the internal clocking circuitry is through a divide-by-two
flip-flop, but minimum and maximum voltage high and low time
specifications must be observed.
XTAL1
XTAL2
C1
C2
GND
-
7/27/2019 Car Light Control-final
42/65
THE 8051 REGISTERS:
The most widely used registers of the 8051 are A (accumulator), B, R0, R1,
R2, R3, R4, R5, R6, R7, DPTR (data pointer), and PC (program counter).All of the above registers are 8-bits, except DPTR and the program counter.
The 8 bots of a register are shown below from the MSB (most significant
bit) D7 to the LSB (least significant bit) D0.
D7 D6 D5 D4 D3 D2 D1 D0
PROGRAM COUNTER:
The program counter points to the address of the next instruction to beexecuted. As the CPU fetches the opcode from the program ROM, the
program counter is incremented to point to the next instruction. The PC is 16
bits wide i.e. it can access program addresses 0000 to FFFFH, a total of 64K
bytes of code.
PSW (PROGRAM STATUS WORD) REGISTER
The PSW contains status bits that reflect the current state of the CPU and isalso called flag register. The PSW contains the Carry bit, the Auxiliary
Carry bit, the two register bank select bits, the overflow flag bit, a parity bit,
and two user definable status flags.
CY PSW.7 Carry flag.
AC PSW.6 Auxiliary carry flag.
--- PSW.5 Available to the user for general purpose.
RS1 PSW.4 Register Bank selector bit 1.
RS0 PSW.3 Register Bank selector bit 0.
OV PSW.2 Overflow flag.
--- PSW.1 User definable bit.
P PSW.0 Parity flag.
CY AC F0 RS1 RS0 OV --- P
-
7/27/2019 Car Light Control-final
43/65
RS1 RS0 REGISTER BANK ADDRESS
0 0 0 00H 07H
0 1 1 08H 0FH
1 0 2 10H 17H
1 1 3 18H 1FH
CY, THE CARRY FLAG
This flag is set whenever there is a carry out from the D7 bit. This flag bit is
affected after an 8-bit addition or subtraction. It can also be set to
1 or 0 directly by an instruction such as SETB C and CLR C where
SETB C stands for set bit carry and CLR C for clear carry.
AC, THE AUXILIARY CARRY FLAG
If there is a carry from D3 to D4 during an ADD or SUB operation, this bit
is set; otherwise, it is cleared. This flag is used by instructions that perform
BCD (binary coded decimal) arithmetic.
P, THE PARITY FLAG
The parity flag reflects the number of 1s in the A (accumulator) register
only. If the A register contains an odd number of 1s, then P=1. Therefore,
P=0 if A has an even number of 1s.
OV, THE OVERFLOW FLAG
This flag is set whenever the result of a signed number operation is too large,causing the high-order bit to overflow into the sign bit.
RAM MEMORY SPACE ALLOCATION IN THE 8051
There are 128 bytes of RAM in the 8051, which are assigned addresses 00 to
7FH. These 128 bytes are divided into three different groups:
-
7/27/2019 Car Light Control-final
44/65
1. A total of 32 bytes from locations 00 to 1H hex are set aside for
register banks and the stack.
2. A total of 16 bytes from locations 20H to 2FH are set aside for bit-
addressable read/write memory.
3. A total of 80 bytes from locations 30H to 7FH are used for read and
write storage, or what is normally called a scratch pad. These
80 locations of RAM are widely used for the purpose of storing data
and parameters by 8051 programmers.
7F
Scratch pad RAM
30
2F
Bit-Addressable RAM
20
1F Register Bank 3
18
17 Register Bank 2
10
0FRegister Bank 1 (stack)
08
07
Register Bank 0
00REGISTER BANKS IN THE 8051
The 32 bytes of RAM which is set aside for the register banks and stack is
divided into 4 banks of registers in which each bank has 8 registers, R0
R7. RAM locations from 0 to 7 are set aside for bank 0 of R0 R7
-
7/27/2019 Car Light Control-final
45/65
where R0 is RAM location 0, R1 is RAM location 1, R2 is location 2, and so
on, until memory location 7 which belongs to R7 of bank 0. The second
bank of registers R0 R7 starts at RAM location 08 and goes to location
0FH. The third bank of R0 R7 starts at memory location 10H and goes to
location 17H; and finally RAM locations 18H to 1FH are set aside for the
fourth bank of R0 R7. The following tables shows how the 32 bytes are
allocated into 4 banks:
Bank 0 Bank 1 Bank 2 Bank 3
STACK IN THE 8051
The stack is a section of RAM used by the CPU to store information
temporarily. This information could be data or an address. The CPU needs
this storage area since there are only a limited number of registers. The
register used to access the stack is called the SP (stack pointer) register. The
R7 7
R6 6
R5 5
R4 4
R3 3
R2 2
R1 1
R0 0
R7 7
R6 6
R5 5
R4 4
R3 3
R2 2
R1 1
R0 0
R7 7
R6 6
R5 5
R4 4
R3 3
R2 2
R1 1
R0 0
R7 7
R6 6
R5 5
R4 4
R3 3
R2
R12 1
R0 0
-
7/27/2019 Car Light Control-final
46/65
stack pointer in the 8051 is only 8 bits wide i.e. it can take values of 00 to
FFH. When the 8051 is powered up, the SP
register contains value 07 which implies that RAM location 08 is the first
location being used for the stack by the 8051. The storing of a CPU register
in the stack is called a PUSH, and loading the contents of the stack back into
a CPU register is called a POP. In other words, a register is pushed onto the
stack to save it and popped off the stack to retrieve it.
PUSHING ONTO THE STACK:
In the 8051 the stack pointer (SP) is pointing to the last used location of the
stack. As data is pushed onto the stack, the stack pointer (SP) is incremented
by one and the contents of the register are saved on the stack. To push the
registers onto the stack, RAM addresses are used.
POPPING FROM THE STACK:
Popping the contents of the stack back into a given register is the opposite
process of pushing. With every pop, the top byte of the stack is copied to the
register specified by the instruction and the stack pointer is decremented
once.
ADDRESSING MODES:
The addressing modes in the microcontroller instruction set are as follows:
1. DIRECT ADDRESSING
In direct addressing, the operand is specified by an 8-bit address field in the
instruction. Only internal RAM and SFRs cab be directly accessed.
2. INDIRECT ADDRESSING
In indirect addressing, the instruction specifies a register that specifies a
register that contains the address of the operand. Both internal and external
RAM can be indirectly accessed.
-
7/27/2019 Car Light Control-final
47/65
The address register for 8-bit addresses can be either the stack pointer or R0
or R1 of the selected register bank. The address register for 16-bit addresses
can be only the 16-bit data pointer register, DPTR.
3. REGISTER INSTRUCTIONS
The register banks, which contain registers R0 through R7, can be accessed
by instructions whose opcodes carry a 3-bit register specification.
Instructions that access the registers this way make efficient use of code,
since this mode eliminates an address byte. When the instruction is
executed, one of the eight registers in the selected bank is accessed. One of
four banks is selected at execution time by the two bank select bits in the
PSW.
4. REGISTER-SPECIFIC INSTRUCTIONS
Some instructions are specific to a certain register. For example, some
instructions always operate on the Accumulator, so no address byte is
needed to point to it. In these cases, the opcode itself points to the correct
register.
5. IMMEDIATE CONSTANTS
The value of a constant can follow the opcode in program memory. For
example,
MOV A, #100
Loads the Accumulator with the decimal number 100. The same number
could be specified in hex digits as 64H.
6. INDEXED ADDRESSING
Program memory can only be accessed via indexed addressing. This
addressing mode is intended for reading look-up labels in program memory.
A 16-bit base register (either DPTR or the Program Counter) points to the
base of the table, and the accumulator is set up with the table entry number.
-
7/27/2019 Car Light Control-final
48/65
The address of the table entry in program memory is formed by adding the
accumulator data to the base pointer.
8051 INSTRUCTION SET
MNEMONIC:
The MNEMONIC column contains the 8051 Instruction Set Mnemonic and
a brief description of the instruction's operation.
OPERATION:
The OPERATION column describes the 8051 Instruction Set in
unambiguous symbology. Following are the definitions of the symbols usedin this column.
Bits of a register inclusive. For example, PC means bits
0 through 10 inclusive of the PC. Bit 0 is always the
least significant bit.
+ Binary addition
- Binary 2s complement subtraction
/ Unsigned integer division
X Unsigned integer multiplication
~ Binary complement (1s complement)
^ Logical And
v Inclusive Or
v Exclusive Or
> Greater than
Not equal to
= Equals
-> Is written into. For example, A + SOper -> A means the
result of the binary addition between A and the Source
Operand is written into A.
A The 8-bit Accumulator Register.
AC The Auxiliary Carry Flag in the Program Status Word
CF The Carry Flag in the Program Status Word
DoperThe Destination Operand used in the instruction.
-
7/27/2019 Car Light Control-final
49/65
-
7/27/2019 Car Light Control-final
50/65
This column gives the machine language hexadecimal opcode for each 8051
instruction.
BYTE:
This column gives the number of bytes in each 8051 instruction.
CYC:
This column gives the number of cycles of each 8051 instruction. The time
value of a cycle is defined as 12 divided by the oscillator frequency. For
example, if running an 8051 family component at 12 MHz, each cycle takes
1 microsecond.
-
7/27/2019 Car Light Control-final
51/65
POWER SUPPLY
Most of the digital circuits operate on 5 volt DC supply which isobtained by the following circuit. The power supply circuit consists ofa step down transformer, bridge rectifier and 7805 voltage regulatorIC.
BRIDGE RECTIFIERS
Bridge rectifier circuit consists of four diodes arranged in the form of a
bridge as shown in figure.
OPERATION:
AC Supply
D1
D2
D3
D4
1
B 2
A
3 4
7805
1000 F + +
--
5 V
DC
-
7/27/2019 Car Light Control-final
52/65
During the positive half cycle of the input supply, the upper end A of the
transformer secondary becomes positive with respect to its lower point B.
This makes Point1 of bridge positive with respect to point2. the diode D1 &
D2 become forward biased & D3 & D4 become reverse biased. As a result a
current starts flowing from point1, through D1 the load & D2 to the
negative end.
During negative half cycle, the point2 becomes positive with respect to
point1. Diode D1 & D2 now become reverse biased. Thus a current flow
from point 2 to point1.
TRANSFORMER:
Transformers are a major class of coils having two or more windings usually
wrapped around a common core made from laminated iron sheets.
It has two coils named primary & secondary. If the current flowing through
primary is fluctuating, then a current will be induced into the secondary
winding. A steady current will not be transferred from one coil to other coil.
Transformers are of two types:
1. Step up transformer
2. Step down transformer
AC
Supply Load+ -
D1
D2
D3
D4
1
B 2
A
3 4
-
7/27/2019 Car Light Control-final
53/65
In power supply we use step down transformer. We apply 220V AC on the
primary of step down transformer. This transformer steps down this voltage
to 9V AC. We give this 9 V AC to rectifier circuit, which convert it to 5V
DC.
REGULATOR:
7805 IC is used as regulator in 5V power supply.
IN 7805 pin no.1 is input pin through which non-regulated signal is applied.
Pin no.3 is grounded & the regulated output is taken from pin no.2.
7805
1 3 2
1 - IN2 - OUT
3 - GND
-
7/27/2019 Car Light Control-final
54/65
RELAYS
It is often desirable or essential to isolate one circuit electrically from
another, while still allowing the first circuit to control the second.
For example, if you wanted to control a high-voltage circuit from your
computer, you would probably not want to connect it directly to the a low-
voltage port on the back of your computer in case something went wrongand the mains electricity ended up destroying the expensive parts inside your
computer.
One simple method of providing electrical isolation between two circuits is
to place a relay between them, as shown in the circuit diagram of figure 1. A
relay consists of a coil that may be energized by the low-voltage circuit and
one or more sets of switch contacts, which may be connected to the high-
voltage circuit.
How Relays Work
In figure 2a the relay is off. The metal arm is at its rest position and so there
is contact between the Normally Closed (N.C.) switch contact and the
'common' switch contact.
-
7/27/2019 Car Light Control-final
55/65
If a current is passed through the coil, the resulting magnetic field attracts
the metal arm and there is now contact between the Normally Open (N.O.)
switch contact and the common switch contact, as shown in figure 2b.
Advantages of Relays
The complete electrical isolation improves safety by ensuring that
high voltages and currents cannot appear where they should not be.
Relays come in all shapes and sizes for different applications and they
have various switch contact configurations. Double Pole Double
Throw (DPDT) relays are common and even 4-pole types are
available. You can therefore control several circuits with one relay oruse one relay to control the direction of a motor.
It is easy to tell when a relay is operating - you can hear a click as the
relay switches on and off and you can sometimes see the contacts
moving.
Disadvantages of Relays
Being mechanical though, relays do have some disadvantages over othermethods of electrical isolation:
Their parts can wear out as the switch contacts become dirty - high
voltages and currents cause sparks between the contacts.
They cannot be switched on and off at high speeds because they have
a slow response and the switch contacts will rapidly wear out due to
the sparking.
-
7/27/2019 Car Light Control-final
56/65
Their coils need a fairly high current to energise, which means some
micro-electronic circuits can't drive them directly without additional
circuitry.
The back-emf created when the relay coil switches off can damage the
components that are driving the coil. To avoid this, a diode can beplaced across the relay coil, as will be seen in anyElectronics in
Meccano circuits that use relays with sensitive components.
Choosing a Relay
When choosing a relay to use in a circuit, you need to bear in mind
properties of both the coil and the switch contacts. Firstly, you will need to
find a relay that has the required number of switch poles for your
application. You then need to make sure that the switch contacts can copewith the voltage and current you intend to use - for example, if you were
using the relay to switch a 60W mains lamp on and off, the switch contacts
would need to be rated for at least 250mA at 240V AC (or whatever the
mains voltage is in your country).
Also of importance is the material that the switch contacts are made of - gold
is good for low-voltages, whereas tungsten is suitable for switching high
voltages and currents.
Finally, you need to choose a relay that has a coil that can be energised byyour low-voltage control circuit. Relay coils are generally rated by their
voltage and resistance, so you can work out their current consumption using
Ohm's Law. You will need to make sure that the circuit powering the coil
can supply enough current, otherwise the relay will not operate properly.
The Latching Relay Circuit
If a relay is connected as shown in figure 3, it will become 'latched' on when
the coil is energised by pressing the Trigger button. The only way to turn the
relay off will then be to cut the power supply by pressing the Reset button(which must be a push-to-break type).
-
7/27/2019 Car Light Control-final
57/65
The technical name for this type of behaviour is 'bistable', since the circuit
has two stable states for its output - on and off. Bistable circuits can also be
constructed using many other components, including the 555 timer IC and
transistors.
What's the point of this circuit? The Normally Open switch contact of the
relay could also be connected to a device such as a motor, as shown by the
dotted connections in figure 3. The device will then run indefinitely untilsome event (maybe triggered by the device) momentarily presses the Reset
button, thereby turning off the coil ready for the Trigger button to be pressed
again.
This system could be used in a model which needs a 'Push to Operate'
button. A motor and gearing system in the model can be used to press the
Reset button to cut the power to the relay coil after the model has been
running for a certain amount of time, or until a certain event has occurred.
Of course, you would have to be sure that there was enough momentum in
the mechanism that the button is released ready for the next cycle.
CAPACITORS
-
7/27/2019 Car Light Control-final
58/65
It is an electronic component whose function is to accumulate charges
and then release it.
To understand the concept of capacitance, consider a pair of metal
plates which all are placed near to each other without touching. If a
battery is connected to these plates the positive pole to one and the
negative pole to the other, electrons from the battery will be attracted
from the plate connected to the positive terminal of the battery. If the
battery is then disconnected, one plate will be left with an excess of
electrons, the other with a shortage, and a potential or voltage
difference will exists between them. These plates will be acting as
capacitors. Capacitors are of two types: - (1) fixed type like ceramic,
polyester, electrolytic capacitors-these names refer to the material they
are made of aluminium foil. (2) Variable type like gang condenser inradio or trimmer. In fixed type capacitors, it has two leads and its value
is written over its body and variable type has three leads. Unit of
measurement of a capacitor is farad denoted by the symbol F. It is a
very big unit of capacitance. Small unit capacitor are pico-farad
denoted by pf (Ipf=1/1000,000,000,000 f) Above all, in case of
electrolytic capacitors, it's two terminal are marked as (-) and (+) so
check it while using capacitors in the circuit in right direction. Mistake
can destroy the capacitor
or entire circuit in
operational.
DIODE
-
7/27/2019 Car Light Control-final
59/65
The simplest semiconductor device is made up of a sandwich of P-
type semi conducting material, with contacts provided to connect the p-
and n-type layers to an external circuit. This is a junction Diode. If the
positive terminal of the battery is connected to the p-type material
(cathode) and the negative terminal to the N-type material (Anode), a
large current will flow. This is called forward current or forward
biased.
If the connections are reversed, a very little current will flow. This is
because under this condition, the p-type material will accept the electrons
from the negative terminal of the battery and the N-type material will give
up its free electrons to the battery, resulting in the state of electrical
equilibrium since the N-type material has no more electrons. Thus there will
be a small current to flow and the diode is called Reverse biased.
Thus the Diode allows direct current to pass only in one direction
while blocking it in the other direction. Power diodes are used in concerting
AC into DC. In this, current will flow freely during the first half cycle
(forward biased) and practically not at all during the other half cycle (reverse
biased). This makes the diode an effective rectifier, which convert ac into
pulsating dc. Signal diodes are used in radio circuits for detection. Zener
diodes are used in the circuit to control the voltage.
Some common diodes are:-
1. Zener diode.
2. Photo diode.
3. Light Emitting diode.
1. ZENER DIODE:-
-
7/27/2019 Car Light Control-final
60/65
A zener diode is specially designed junction diode, which can operate
continuously without being damaged in the region of reverse break down
voltage. One of the most important applications of zener diode is the design
of constant voltage power supply. The zener diode is joined in reverse bias
to d.c. through a resistance R of suitable value.
2. PHOTO DIODE:-
A photo diode is a junction diode made from photo- sensitive
semiconductor or material. In such a diode, there is a provision to allow the
light of suitable frequency to fall on the p-n junction. It is reverse biased, but
the voltage applied is less than the break down voltage. As the intensity of
incident light is increased, current goes on increasing till it becomes
maximum. The maximum current is called saturation current.
3. LIGHT EMITTING DIODE (LED):-
When a junction diode is forward biased, energy is released at the
junction diode is forward biased, energy is released at the junction due to
recombination of electrons and holes. In case of silicon and germanium
diodes, the energy released is in infrared region. In the junction diode made
of gallium arsenate or indium phosphide, the energy is released in visible
region. Such a junction diode is called a light emitting diode or LED.
RESISTANCE
Resistance is the opposition of a material to the current. It is measured
in Ohms ( ). All conductors represent a certain amount of resistance, since
no conductor is 100% efficient. To control the electron flow (current) in a
predictable manner, we use resistors. Electronic circuits use calibrated
lumped resistance to control the flow of current. Broadly speaking, resistor
-
7/27/2019 Car Light Control-final
61/65
can be divided into two groups viz. fixed & adjustable (variable) resistors. In
fixed resistors, the value is fixed & cannot be varied. In variable resistors,
the resistance value can be varied by an adjuster knob. It can be divided into
(a) Carbon composition (b) Wire wound (c) Special type. The most common
type of resistors used in our projects is carbon type. The resistance value is
normally indicated by colour bands. Each resistance has four colours, one of
the band on either side will be gold or silver, this is called fourth band and
indicates the tolerance, others three band will give the value of resistance
(see table). For example if a resistor has the following marking on it say red,
violet, gold. Comparing these coloured rings with the colour code, its value
is 27000 ohms or 27 kilo ohms and its tolerance is 5%. Resistor comes in
various sizes (Power rating). The bigger, the size, the more power rating of
1/4 watts. The four colour rings on its body tells us the value of resistor
value as given below.
COLOURS CODE
Black--------------------------------------------0
Brown-------------------------------------------1
Red----------------------------------------------2
Orange------------------------------------------3
Yellow------------------------------------------4
Green--------------------------------------------5Blue----------------------------------------------6
Violet--------------------------------------------7
Grey---------------------------------------------8
White--------------------------------------------9
The first rings give the first digit. The second ring gives the seconddigit. The third ring indicates the number of zeroes to be placed after the
digits. The fourth ring gives tolerance (gold 5%, silver 10%, No colour
20%).
-
7/27/2019 Car Light Control-final
62/65
In variable resistors, we have the dial type of resistance boxes. There
is a knob with a metal pointer. This presses over brass pieces placed along a
circle with some space b/w each of them.
Resistance coils of different values are connected b/w the gaps. When
the knob is rotated, the pointer also moves over the brass pieces. If a gap is
skipped over, its resistance is included in the circuit. If two gaps are skipped
over, the resistances of both together are included in the circuit and so on.
A dial type of resistance box contains many dials depending upon the
range, which it has to cover. If a resistance box has to read upto 10,000 , it
will have three dials each having ten gaps i.e. ten resistance coils each of
resistance 10 . The third dial will have ten resistances each of 100 .
The dial type of resistance boxes is better because the contactresistance in this case is small & constant.
TRANSISTOR
The name is transistor derived from transfer resistors indicating a
solid state Semiconductor device. In addition to conductor and insulators,there is a third class of material that exhibits proportion of both. Under some
conditions, it acts as an insulator, and under other conditions its a
conductor. This phenomenon is called Semi-conducting and allows a
variable control over electron flow. So, the transistor is semi conductor
device used in electronics for amplitude. Transistor has three terminals, one
is the collector, one is the base and other is the emitter, (each lead must be
connected in the circuit correctly and only then the transistor will function).
Electrons are emitted via one terminal and collected on another terminal,
while the third terminal acts as a control element. Each transistor has a
number marked on its body. Every number has its own specifications.
There are mainly two types of transistor (i) NPN & (ii) PNP
NPN Transistors:
-
7/27/2019 Car Light Control-final
63/65
When a positive voltage is applied to the base, the transistor begins to
conduct by allowing current to flow through the collector to emitter circuit.
The relatively small current flowing through the base circuit causes a much
greater current to pass through the emitter / collector circuit. The
phenomenon is called current gain and it is measure in beta.
PNP Transistor:
It also does exactly same thing as above except that it has a negative
voltage on its collector and a positive voltage on its emitter.
Transistor is a combination of semi-conductor elements allowing a
controlled current flow. Germanium and Silicon is the two semi-conductor
elements used for making it. There are two types of transistors such asPOINT CONTACT and JUNCTION TRANSISTORS. Point contact
construction is defective so is now out of use. Junction triode transistors are
in many respects analogous to triode electron tube.
A junction transistor can function as an amplifier or oscillator as can a
triode tube, but has the additional advantage of long life, small size,
ruggedness and absence of cathode heating power.
Junction transistors are of two types which can be obtained while
manufacturing.
The two types are: -
1) PNP TYPE:This is formed by joining a layer of P type of
germanium to an N-P Junction
NP
-
7/27/2019 Car Light Control-final
64/65
2) NPN TYPE:This is formed by joining a layer of N type germanium
to a P-N Junction.
Both types are shown in figure, with their
symbols for representation. The centre section is
called the base, one of the outside sections-the
emitter and the other outside section-the collector. The direction of the
arrowhead gives the direction of the conventional current with the forward
bias on the emitter. The conventional flow is opposite in direction to the
electron flow.
OPERATION OF PNP TRANSISTOR:-
A PNP transistor is made by sand witching two PN germanium or
silicon diodes, placed back to back. The centre of N-type portion is
extremely thin in comparison to P region. The P region of the left is
connected to the positive terminal and N-region to the negative terminal i.e.
PN is biased in the forward direction while P region of right is biased
negatively i.e. in the reverse direction as shown in Fig. The P region in the
forward biased circuit is called the emitter and P region on the right, biasednegatively is called collector. The centre is called base.
The majority carriers (holes) of P region (known as emitter) move to
N region as they are repelled by the positive terminal of battery while the
electrons of N region are attracted by the positive terminal. The holes
overcome the barrier and cross the emitter junction into N region. As the
width of base region is extremely thin, two to five percent of holes
recombine with the free electrons of N-region which result in a small basecurrent while the remaining holes (95% to 98%) reach the collector junction.
The collector is biased negatively and the negative collector voltage aids in
sweeping the hole into collector region.
As the P region at the right is biased negatively, a very small current
should flow but the following facts are observed:-
N P N
-
7/27/2019 Car Light Control-final
65/65
1) A substantial current flows through it when the emitter junction is biased
in a forward direction.
2) The current flowing across the collector is slightly less than that of the emitter,and
3) The collector current is a function of emitter current i.e. with the
decrease or increase in the emitter current a corresponding
change in the collector current is observed.
The facts can be explained as follows:-
1. As already discussed that 2 to 5% of the holes are lost in recombination with the
electron n base region, which result in a small base current and hence the collector
current is slightly less than the emitter current.
2. The collector current increases as the holes reaching the collector
junction are attracted by negative potential applied to the collector.
3. When the emitter current increases, most holes are injected into the
base region, which is attracted by the negative potential of the collector
and hence results in increasing the collector current. In this way emitter
is analogous to the control of plate current by small grid voltage in a
vacuum triode.
Hence we can say that when the emitter is forward biased and collector
is negatively biased, a substantial current flows in both the circuits. Since a
small emitter voltage of about 0.1 to 0.5 volts permits the flow of an
appreciable emitter current the input power is very small. The collector voltagecan be as high as 45 volts.