PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed.
TITLE OF THE INVENTION:-
Automatic headlight dimmer
FIELD OF THE INVENTION:-
This invention relates to safety devices used in automobiles. Particularly this invention is about automatic headlight dimmer. In this invention we reduce the risk of vehicle accidents during night driving by dimming the headlights of coming vehicles.
BACKGROUND OF THE INVENTION:-
Headlights are used to lighten up the way for vehicles during night time driving, they are fitted at front of a vehiclejor driving purpose and to cover maximum distance in sight maximum amount of light is provided by high beam.Jn order to see at short range low beam is used, also it is used to prevent headlight glare produced by high beam from being cast into drivers eyes of opposite vehicle In night time, many accidents caused are due to headlight glare. Headlight glare of coming vehicles makes driver unable to see road and this results in stressful driving and also can be reason for accidents. Many drivers are so modest, even if we signal them by pass they never shift to low beam.
So my invention is capable of dimming headlights of coming vehicles by using wireless communication. US 1694511
this invention contemplates providing an automobile at the front end there of with a light conducting medium affecting the resistance of an electric current or selenium cell in circuit with conventional electric headlights, whereby when the automobile approaches a well lighted area said

headlights will be automatically turned down or dimmed and when it is travelling along a dark roadway the headlights will be turned on to more or less full capacity by the action of the selenium cell, so that this important part of the proper operation of an automobile need not require the attention of the driver.
US 2959709
This invention relates to automatic means for dimming the headlights of a motor vehicle, and more particularly to a headlight dimming system of the type employing photo-sensitive detector means acting in response to the headlight beam of an approaching vehicle to automatically dim the headlights of the vehicle equipped with the detector means. A main object of the invention is to provide a novel and improved automatic headlight dimming system for a motor vehicle, said system being energized directly from the vehicle battery, requiring no additional power supply means, involving relatively simple components, and being reliable in operation.
US 3325680
This invention relates to automatic means for dimming the headlights of a motor vehicle, and more particularly to a headlight dimming system of the type employing photosensitive detector means acting in response to a selected level of incident light on the detector to automatically dim the headlights of a vehicle equipped with .the 'detector means. Most modern vehicles are equipped with headlights having multiple filaments and/or separate lamps so arranged as to direct the light beams there from onto different portions of a roadway in front of the Vehicle, the headlights being referred to as the high beams and/or low beams according to the character thereof. In a typical headlight system, operation of the dash switch causes the low beam filaments to be continuously energized, while the high beam filaments are manually turned on or off by a conventional type of floor switch.
In the interest of preventing safety hazards to both the driver of an oncoming vehicle, due to the blinding effect of the high beams of an approaching vehicle, and to the operator of that vehicle himself, due to the distraction of operating the foot switch to manually dim his lights, it has been proposed heretofore to provide a system for automatically dimming the high beams in response to light rays from an oncoming car, as well as .in a lighted area, such as in a city, where

there is a sufficient amount of ambient light for safe driving conditions without the necessity of having the high beams on. Such prior art systems are generally inadequate for a variety of reasons; such as being bulky, complex, slow-acting, and so generally-unreliable as to negate their acceptance by the general public. In addition, many of the prior art systems do not have any provision for enabling the driver to override the automatic system when he is not satisfied by its selection of high or low beams.
The present invention provides an automatic headlight dimming system which overcomes all of the problems and faults of the earlier systems. It is sufficiently sensitive to dim the headlights at the desired light level, and at the same time is simple yet rugged, compact, fast-acting, and is stable over a wide range >of operating voltages. It employs relatively simple, inexpensive components, has no warm up delay or temperature sensitivity, and is extremely reliable. It is adapted for ready installation and easy interconnection with existing headlight energizing circuits, is easily serviced, and is energized directly from the vehicle battery, requiring no additional power supply means.
US 5086253
An apparatus within a vehicle including a plurality of high beams in electrical communication with an automatic circuit to direct voltage to each associated high beam, wherein a photo-transistor is arranged in parallel circuitry to a relay coil and resistor, with the junction transistor arranged to interface between the first and the adjustable resistor respectively. A modifies detector circuit includes a second resistor in series with the relay coil to effect a time delay in actuation of the high beam members of the vehicle. A third junction transistor is arranged in a third circuit parallel to the first and second circuit to direct current to the respective high beam for increased sensitivity relative to the incoming light source from a remote vehicle.
so all these US 1413415, US169411, US 2959709, US 3325680, US 5086253 patents came up with an idea of using photo sensor or photo transistor so that it will be installed in every car and it will lower/dim the high beam according to signal received from photo sensor. But elevation of head lights due to different sizes of vehicles may create problem. If direction of high beam is not stable of coming vehicle due to any reason like uneven geometry of roads or any other thing, continuous switching of headlights may occur which is not desirable.

US 9313862 B1
A system by which high beam lights on motor vehicles are automatically dimmed when a similarly equipped vehicle is approaching from an oncoming direction utilizes transmitted radio frequency (RF) signals between vehicles which operate at" a preset range. Vehicles equipped with the system also comprise front, rear, and side vehicle sensors to differentiate RF signals transmitted from oncoming or trailing vehicles. A receiving antenna portion of the system picks up an RF signal, verifies there are no proximal side or trailing vehicles, and deactivates the high beam circuit for a preset period of time. All vehicles equipped with the system provide an RF signal having a digital identification code to prevent interference. The system is preferably introduced as a retrofit kit for installation upon existing vehicles; however, the system may also be incorporated on new vehicles.
As above patent is using RF signals its receiver is having conventional circuit consisting RF amplifier, mixer, carrier wave generator, tuner/filter and all. In order to obtain only D.C. signal my invention has dropped all the stages after RF amplifier and o/p of said amplifier will be converted into D.C. line voltage by using rectifier.
In detail patent US 9313862 B1 is having a switch that enables driver to shut this circuit down, by using this switch the purpose of this safety device will not be maintained, So my invention doesn't have any kind of on/off switch and if driver is needed to use high beam he can simply use pull lever provided for flash/signal purpose, this is the only provision for override this circuit and thus purpose of this safety device will be maintained.
OBJECTS OF INVENTION
One object is to reduce risk of accidents / collisions at night due to headlight glare.
Another object is to make device more universal so that it can be used for any vehicle without
disturbing previous headlight circuit, so all used cars can also install them very easily.
and last object is to make circuit so simple that everyone can afford and can be fitted in two
wheelers, four wheelers and heavy transports.

as we are using radio communication, it should work properly at all different frequencies of different vehicle
SUMMARY OF INVENTION.
Basically many drivers are facing problems with night driving due to headlight glare, many projects has been done over this problem, like dimming of lights using signal from photo sensor and image recognition system.
But headlights dimming by using photo sensor are not reliable due to its positioning of sensor with respect to headlights of opposite vehicle and their sizes like sports cars, sedans, SUVs, trucks, heavy vehicles. Also these sensors get disturbed by city lights and if sensors are constrained they can't work properly if elevations of headlights are different for different vehicles, so this system is not reliable, and if we use image recognition system, it costs more than normal people can afford. Even if you use them, they can't allow you to dim lights of coming vehicle as all vehicles are not installed with headlight dimming circuit.
My circuit enables you to dim the lights of opposing vehicle by establishing radio communication between vehicles.
Radio signals will be transmitted within a specified range in which headlights affects driver. If two or more vehicles comes in range of each other, radio signal transmitted by transmitter of one vehicle will be received by receiver of other vehicles also transmitting car will receive signal from other vehicles and received signal will dim the lights of vehicle.
A typical signal transmitter is used in circuit but major change is done in receiver circuit. A signal transmitted from one car is received by other cars, signal received will be amplified to a certain voltage. Amplified signal will be rectified and given to the Relay so that relay shift from high beam to low beam. And when signal is lost, there will be no signal to relay and it will obtain initial position. If no signal is being received, there can be some noise and this noise should not generate any signal so that a filter is set for a fixed bandwidth and integrated in RF Amplifier will eliminate noise.

BRIEF DESCRIPTION OF INVENTION.
The invention will be described in relation to the accompanying drawings in which:
fig. (1) Illustrate sector type antenna and way of travelling signal
In fig. (1) 46 - sector antenna
47 - Signal waves transmitted by sector antenna
fig. (2) and fig. (3) Illustrate the circuits used in inventions
fig. (4) Illustrate position of relay in circuit
In fig. (3) 40 - D.C. Signal
41 - High Beam Signal from Switch
42 - Low Beam port in relay
43 - High Beam port in relay
44 - Low beam signal from switch
45 - Signal for pass/flash
DETAILED DESCRIPTION OF ACCOMPANYING ' DRAWINGS.
fig. (1) Describes the use of sector antenna (46). Signal waves of sector antenna (47) are transmitted with an angle of 180 degree on front side. It is difficult to manufacture as compared to omnidirectional/ telescopic antenna, but mass production may makes it affordable.
Fig. (2) Describes a simple transmitter circuit.
It consists:-
1) Signal generator:

As we are using radio communication, signals are electromagnetic waves and it is generated in Signal generator. Using same frequency for every vehicle may cause interference resulting in inefficient operation.
To avoid interference every device should have a particular frequency within a fixed bandwidth. This unique frequency is assigned with device ID.
As we need better range and constant amplitude we are using frequency modulation. Signal will be provided by signal generator and given to frequency modulator.
2) Carrier wave Generator:
Carrier wave Generator is used to produce carrier wave with constant amplitude and frequency. As the name describes 'carrier-wave' carries data signal.
3) Modulator:
The function of modulator is to enhance data signal over carrier wave. Modulation is done to reduce height of antenna
4) Transmitter Antenna:
Transmitter antenna will transmit the signal within range. Antenna used will be type of sector antenna (46).
As sector antenna (46) have good range as compared to omnidirectional antenna, it must be preferred to use. also its signals never reaches to vehicle on either side, behind, on/under the bridge, sector antenna can be made in shape of logo or number plate. Antenna will be designed to transmit signals within 100 meters range
Fig. (3) Describes our modified radio receiver circuit, in order to reduce response time we have reduced further stages in receiver circuit. Now it has: 1) Receiver Antenna:
Receiver antenna is different than transmitter antenna. As the carrier frequencies of transmitter and receiver, will be same for same vehicle. The receiving antenna will take signal from transmitter of same vehicle, so different antennas must be installed. Receiver antenna will be installed behind or side by side to transmitter antenna.
If there is more than one signal available for receiver antenna, a signal with power more than others will be chosen at first and thus interference will never occur.

Antenna must be designed to receive all signals in particular bandwidth within 100 meters as at this distance headlight glare creates problem. Antenna will be designed according to bandwidth so that only frequencies within this bandwidth will be received
2) RF Amplifier:
RF Amplifier will have a tuner just before actual amplifier and will be used for allowing particular bandwidth set for this system. Types of tuners will be chosen according to bandwidth.
Signal obtained from receiver antenna will be amplified in RF amplifier. Amplifier will increase voltage considering voltage drops in circuit before it reaches to end user.
3) Limiter:
When signal is not being received, due to any random things noise will be generated, this noise may produce unnecessary signal. In order to prevent any false signal a Limiter will be used after RF Amplifier.
A fixed threshold is set for limiter. any signal above threshold will be accepted and any signal below threshold limit will be considered as noise and will be discarded.
4) Rectifier:
The output of RF Amplifier is given to full wave rectifier. The output of RF amplifier will be used as A.C. voltage and will be converted in fluctuating D.C. voltage in rectifier.
5) Filter:
The output of rectifier i.e. fluctuating D.C. will be given to R-L-C filter circuit to eliminate fluctuations and pure D.C. voltage will be obtained.
6) Voltage regulator:
Voltage regulator is used for removing ripples generated and to provide constant D.C. line So voltage regulator is used to maintain voltage for Relay. 6) Relay:
Here we are going to use 5-pin electromagnetic relay. Output of filter i.e. D.C. signal(40) is given to Relay. If there are small ripples in D.C. voltage, lower voltage in ripples must be greater than requirement of relay so that fluctuations will never occur in operation of headlights.
Relay must be placed in the path of high beam just after high-low beam switch. When D.C. signal (40) is provided, electromagnet pulls the strip and connects it to other pole which is connected to low beam.

Signal from manual override lever which we use for pass/flash (45) will be joined in High beam line after relay, so that if you need high beam you can pull lever as we normally do and it will not be affected by relay. If we provide an on/off switch which will override system and provide continuous high beam, purpose of this device will be violated.
Fig. (A) Shows position of strip in relay when signal is not being received, as radio signal-is not being received there is no D.C. signal(40) to Relay, so strip will be remain on its default position, and high beam signal from switch(41) will be given to high beam(43) port
Fig. (B) Shows position of strip in relay when signal is being received and utilized as D.C. signal (40) for relay. When a radio signal is received it is converted into D.C. signal (40) and given to electromagnet of Relay, as electromagnet is energized it will attract the strip and high beam signal from switch(41) will be given to low beam(42) terminal. Thus as signal is received headlights are shifted from high beam to low beam

claim,
I claim,
' "" 1. this circuit will be used for automatic dimming of headlights of coming vehicle, so that, for proper implementation of this idea, this circuit must be installed in every vehicle.
2. During night time driving, also vehicles coming from behind creates problem, their headlight glare gets reflected from rear view mirror, so that one more transmitter can be placed at backside of vehicle with same frequency as front and specific range (but less than front).
3. Today more than 1 billion vehicles are registered and running on roads in the world, setting each vehicle at different and unique frequency is difficult so that, a service same as mobile operators must be adopted. All Devices must have single bandwidth as there is no operator to connect different bandwidths. Every device ID must have different frequency so that it will have serial numbers like mobile numbers.

4. As speed of vehicle increases, driver needs to see at longer distance so we use high beam, so that some people came up with an idea of switching headlights from low beam to high beam depending upon speed, but they were obstructed by the question that how headlights can be dimmed if a vehicle is coming from opposite, so now they can implement their idea with help of this circuit.
5. Device will be made with given ID during manufacturing or all devices will be manufactured same and ID will be given by SIM (subscriber's identity module) like thing.