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CONTENTS
1. Why a Project?
2. Introduction
3. Principle
4. Chronology
5. Circuit Detail
- Circuit Description & Working
- Circuit Layout
- Component List
6. PCB Details
- PCB Description
- PCB Layout
7. Assembling
8. Conclusion
9. Reference
10. Ideas which could not be implemented
WHY A PROJECT?
A student specially technical student is expected to do some experimentation
and research work on the subject, which he thought in the class textbook during the
course of his studies. Such an effort when well organized with a definite aim or
purpose is called a project.
The object of a project is to envelope technical thinking and induced the
student to make an ordinary analysis to the situation following at hand so as to
search a definite conclusion.
By doing project student display’s his spirit of inquiring creating & criticizing
way of solving a problem through understanding of existing situation, independent
thinking and ability to understand basic fact.
INTRODUCTION
In an automobile headlight, a 'meeting' beam (dip beam) is provided in addition to
the driving beam (high beam) so as to reduce the dazzle for those approaching
head-on to the vehicle.
The Auto Dipping Device for a head light is intended to automatically change the
Headlight Circuit to either driving beam or dip beam given a particular set of road
conditions, without the intervention of the driver. The present practice is to operate
the dip switch manually.
The function of the headlight is to illuminate the road ahead of the automobile so as
to reveal objects ahead from a safe distance; at the same time it should cause
minimum discomfort and glare for drivers coming from the opposite side.
Manual dipping is not being done satisfactorily in India due to a variety of reasons,
which includes sheer physical strain involved in operation of the dipper switch
hundreds of times every night. (The total for a single night will be 1000 if we consider
8 hours of traveling and one encounter every one-minute and could exceed this
number if one travels on roads with dense traffic). The other reason includes a
general tendency of paying more attention to steering control at the cost of dipping
during a critical vehicle meeting situation especially in the case of heavy loaded
vehicles. More reasons are the physiological and psychological state of a driver,
which is influenced by a variety of factors like working hours, economic issues and
social factors etc. Another major cause is 'ego problem', which makes each one wait
till the other person initiates dipping, which may not happen.
A frequent cause of accidents at nights is the glare caused by oncoming vehicles
which momentarily blinds the driver's vision. It takes three to eight seconds for a
person with good eyesight to recover from the glare and during this time the vehicle
will have covered a long distance in utter darkness and it will be sheer luck if it
escapes an accident.
The observations of the study group on road safety (Constituted by Government of
India vide Resolution No.19 (14) 68, June 3, 1969) regarding the conditions of our
national highways are:
“The Indian roads are all essentially very narrow, tortuous in their alignment
and suffer from many inadequacies, vis-à-vis the present day motor traffic
which has registered a phenomenal increase during the post-Independence
period. The other conditions of the roads like poor shoulders, narrow culverts
and bridges, sharp and numerous curves and steep gradients which limit the
sight distance, numerous low level causeways and submersible bridges are
perennial hazards. All the above tell on the nerves of the driver, causing
fatigue and leading to errors and misjudgment while driving”.
All the above indicate the importance of dipping of headlights in a country like India,
so as to avoid the problem of glare which impairs the visibility which is vital for safe
driving in a meeting situation during the night. This leads to the conclusion that an
Auto Dipping Device can go a long way towards safety enhancement.
WHAT IS AN AUTO DIPPER?
An Auto Dipper is a device capable of changing over the circuit of head light without
the intervention of the driver given a particular set of objective road conditions. Its
primary aim is to reduce the dazzle for the observer approaching ahead of the
vehicle while ensuring that the user will not be put to inconvenience.
THE FUNCTIONAL REQUIREMENTS ON A DARK ROAD
The basic function of an auto dipper is to maintain the head lamps in either driving
beam or meeting beam automatically depending on the opposing traffic.
AUTOMATIC DRIVING BEAM
It has to bring into operation the driving beam if there is no oncoming vehicle.
Necessarily this means the auto dipper must be immune to the signals from; street
lamps, moonlight, road reflectance, solar radiation during the late dusk and early
dawn.
AUTOMATIC DIP BEAM
It has to bring into operation the meeting beam from both headlights whenever an
oncoming vehicle approaches to within about say 250 meters with its headlights in
driving beam until the vehicle is about to pass. The auto dipper, after bringing into
operation the dip beam, should logically be capable of continuing the operation of the
headlights in dip beam, if the headlights of the oncoming vehicle were also shifted to
the dip beam.
Our project is designed based on the above conceptual framework and is believed to
cater to the actual road conditions in a way convenient to the user and is expected to
relieve him from the repetitive task of operating the dipper switch. The auto dipper is
not to replace the human judgment but only to assist the user and the ultimate
control is left with the user.
PRINCIPLE
A circuit is designed which uses a LDR(light dependent resistor) to sense the light
emitted by the vehicle coming from the opposite direction. This light sensed by the
LDR is used to send signals to the circuit to trigger the command to a upper or the
dipper circuit depending on the amount of light emitted by the vehicle coming from
opposite direction.
CHRONOLOGY
The following steps have been followed in carrying out the project:
1. Study the books on the relevant topic.
2. Understand the working of the circuit.
3. Prepare the circuit diagram.
4. Prepare the list to components along with their specification estimate .the cost
and procure them after carrying out market survey.
5. Plan and prepare PCB for mounting all the components.
6. Fix the components on the PCB and solder them.
7. Test the circuit for the desired performance.
8. Trace and rectify faults if any.
9. Give good finish to the unit.
10. Prepare the project report.
CIRCUIT DETAILS
CIRCUIT DESCRIPTION & WORKING:-
This project is very useful in car head light automatically. During night time, car head
light upper dipper changes automatically. The 9 Volt supply is fed in a controlling
circuit of IC 555. In this project IC 555 is used as a switch. One light dependent
resistance (LDR) is also used to act with light intensity. The resistance of the L.D.R
increases or decreases on the intensity of light. When light falls on L.D.R its
resistance decreases and in darkness the resistance increases. In the circuit IC 555
is used as a timer. Pin No.2 of the IC is earthed through 10 k preset which keeps the
flip-flop system of the IC at a high state. Pin No. 3 of the IC is the output pin and
remains at a low state. The IC does not operate until light falls on the LDR. When
light falls on L.D.R., the resistance of the L.D.R. decreases, as a result of
which, Pin No. 2 of the IC gets positive voltage, the Pin No.2 is trigger pin which
can trigger the required circuit ON. When light falls on the LDR the Upper circuit
gets switched OFF while the Dipper circuit gets switched ON and the vice- versa
CIRCUIT LAYOUT:-
COMPONENT LIST:-
Components Total Qty. Details
Battery 1 9V
IC 1 555 Timer
Capacitor 1 4.7Kohm
Resistance 1 100 Kohm
Variable resistance 1 10 Kohm
LDR 1 Light dependent resistance
Wire - -
Other misc 1 Board, Wire, Socket For U1, Case, Mains Plug, Socket
9 VOLT BATTERY:-
A nine-volt battery, sometimes referred to as a PP3 battery, is shaped as a rounded
rectangular prism and has a nominal output of nine volts. Its nominal dimensions are
48 mm × 25 mm × 15 mm (ANSI standard 1604A). PP3 actually refers to the type of
connection or snap that is on top of the battery . The PP3 connector (snap) consists
of two connectors: one smaller circular (male) and one larger, typically either
hexagonal or octagonal (female). The connectors on the battery are the same as on
the connector itself -- the smaller one connects to the larger one and vice versa.
The battery has both the positive and negative terminals on one end. The negative
terminal is fashioned into a snap fitting which mechanically and electrically connects
to a mating terminal on the power connector. The power connector has a similar
snap fitting on its positive terminal which mates to the battery. This makes battery
polarization obvious since mechanical connection is only possible in one
configuration. The clips on the 9-volt battery can be used to connect several 9-volt
batteries in series. One problem with this style of connection is that it is very easy to
connect two batteries together in a short circuit, which quickly discharges both
batteries, generating heat and possibly a fire. While this is a danger, the same thing
can be done with multiple 9 volt batteries to create higher voltage (they can snap
together). The wiring usually uses black and red wires, red for positive, and black for
negative.
Inside a PP3 there are ordinarily six alkaline or carbon-zinc 1.5 volt (nominal) cells
arranged in series. These are either AAAA cells, or special flat, rectangular cells.
The exact size of the constituent cells varies from brand to brand -- some brands are
slightly longer than others -- as does the manner in which they are joined together.
Some brands use soldered tabs on the battery, others press foil strips against the
ends of the cells.
Very cheap versions may contain only five 1.5 volt cells. Rechargeable NiCd and
NiMH batteries have various numbers of 1.2 volt cells. Lithium versions use three 3.2
V cells - there is a rechargeable lithium polymer version. There is also a Hybrio
NiMH version that has a very low discharge rate (85% of capacity after 1 year of
storage). .
555 TIMER IC:-
One of the most versatile linear integrated circuit is the 555 timer. The IC was
designed and invented by Hans R. Camenzind. It was designed in 1970 and
introduced in 1971 by Signetics (later acquired by Philips). The original name was
the SE555/NE555 and was called "The IC Time Machine".[1] The 555 gets its name
from the three 5-kohm resistors used in typical early implementations. Depending on
the manufacturer, it includes over 20 transistors, 2 diodes and 15 resistors on a
silicon chip installed in an 8-pin mini dual-in-line package. Since its debut the device
has been used in a number of novel an useful application. A sample of these
application includes monostable and stable multivbratores dc-dc converters digital
logic probes waveform generators analog frequency meters and tachometer
temperature measurement and control infrared transmitter burglar and toxic gas
alarms, voltage regulator, electric eyes and may other The 555 is monolithic timing
circuit that can produced accrued and highly stable time delays an oscillation. The
timer basically operated in one of et two modes either as monostable (one
shot)multivibrotor or as an stable (free running )multivibrator. The device is available
as an 8 pin metal can an mini DIP of 14 pin DIP. The SE555 is designed for the
operation temperature renege from 55 degree to +5 to 18 v supply voltage in both
free running (astable ) and onset (monostable) modes; it has an adjustable duty
cycle; timing is from microseconds through hours; it has ha high current output; it can
source of sink 2000mA;the output can drive TTL and has a temperature stability of
50 parts per million(ppm) per degree Celsius change in temperature of equivalently
0.005% per degree Celsius. Like general-purpose op-amps the 555 timer is reliable
to a number of factors depending upon (I0) Material used for fabrication a resistance
(II) Wattage an physical size (III) Intended application (iv) Ambient temperature
rating (v) Cost basically the resistor can be splinted in to the following four parts with
the construction view point (1) Base(2) Resistance element (3) Terminals (4)
Protective means. The following characteristics are inherent in all resistance’s an
may be controlled by design considerations and choice of material I.e. Temperature
co–efficient Voltage co–efficient of resistance high frequency characteristics power
rating and reseating tolerance voltage retting of Resistors Resistance’s may be
classified as (1) Fixed (2) semivariable (3) Variable resistance’s We have used
carbon resistance’s. Resistors can be integrated into hybrid and printed circuits, as
well as integrated circuits. Size, and position of leads (or terminals) are relevant to
equipment designers; resistors must be physically large enough not to overheat
when dissipating their power.
Colour Code:
VARIABLE RESISTORS:-
Variable resistors consist of a resistance track with connections at both ends and a wiper which moves along the track as you turn the spindle. The track may be made from carbon, cermet (ceramic and metal mixture) or a coil of wire (for low resistances). The track is usually rotary but straight track versions, usually called sliders, are also available.
Variable resistors may be used as a rheostat with two connections (the wiper and just one end of the track) or as a potentiometer with all three connections in use. Miniature versions called presets are made for setting up circuits which will not require further adjustment.
Variable resistors are often called potentiometers in books and catalogues. They are specified by their maximum resistance, linear or logarithmic track, and their physical size. The standard spindle diameter is 6mm.
The resistance and type of track are marked on the body: 4K7 LIN means 4.7 k linear track. 1M LOG means 1 M logarithmic track.
Some variable resistors are designed to be mounted directly on the circuit board, but most are for mounting through a hole drilled in the case containing the circuit with stranded wire connecting their terminals to the circuit board.