FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
"A METHOD AND A SYSTEM FOR AUTOMATICALLY SWITCHING ON/OFF HEADLAMP IN TWO-WHEELED
VEHICLES"
MINDA INDUSTRIES LIMITED of Village Nawada Fatehpur, P.O. Sikanderpur Badda, Distt. Gurgaon, Haryana -122004
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
The present invention generally relates to an automatic headlight ON/ OFF control system used in two-wheeled vehicles. In particular, the present invention relates to a method and system for automatically switching ON/ OFF headlight of a vehicle depending upon the ambient light conditions in the vicinity of the vehicle.
BACKGROUND OF THE INVENTION
Generally, in vehicles, headlights and other lights are provided for safe driving at night. Also, many states have laws, which impose the use of the headlight during precipitation i.e. when it is raining or snowing. Even during broad daylight, it is easier for driver to see a farther vehicle if the headlight and taillight of vehicles is illuminated. Usually, in vehicles a manually operable switch is provided which controls the headlight and other lights. Sometimes a driver forgets to switch 'ON' the lights or intentionally does not switch ON the headlight during night and thus creates safety hazard for others on the road. Another problem associated with controlling vehicle lights manually is the inadvertent failure to turn the lights OFF when the vehicle is in standing condition. If the driver leaves the headlight of the vehicle ON for any length of time, then the current drawn from the headlight bulb will drain the battery of vehicle. However, such situations can be avoided by alerting the driver that the headlight is still ON by means of an alarm or bell.
In automobile, drivers prefer certain systems to be adjusted automatically based on weather and day light condition such as drivers prefer headlight to be in ON condition while driving at night, in rain or while passing through a tunnel, driver's attention is diverted and is unable to focus on driving. Conventionally, there exist various methods and automatic headlight control systems utilizing an ambient light sensor which automatically activates the headlamp to the 'ON' position during night time i.e. in low ambient light driving condition and vice-versa turn them to 'OFF' condition during high ambient light condition. Conventional mechanisms eliminate a need for the driver to manually control the headlamp. The day light sensor provides an output signal to control unit and switches the headlamp ON.

However, conventional methods and systems for automatically switching ON/ OFF headlight in two wheeled vehicles have a drawback in that they consist of a light sensor employing a photodiode having a spectral response curve that diverges significantly from the spectral sensitivity of the human eye.
Therefore, there is a need to provide a method and system for automatically switching ON/ OFF headlight in two wheeled vehicles which can overcome the above mentioned problem and thus provides a sensor having a spectral sensitivity similar to human eyes.
OBJECT OF THE INVENTION
The primary objective of the present invention is to provide a method and a system for automatically switching ON/ OFF headlamp in accordance with the incident light conditions in vicinity of the vehicle.
Another object of the present invention is to provide a system comprising a sensor which has a spectral sensitivity similar to human eyes.
SUMMARY OF THE INVENTION
The present invention generally relates to an automatic headlight ON/ OFF control system used in two-wheeled vehicles. In particular, the present invention relates to a method and system for automatically switching ON/ OFF headlight of a vehicle depending upon the ambient light conditions in the vicinity of the vehicle.
According to one aspect of the present invention, a method of automatically switching on/off headlamp of two-wheeled vehicles, said method comprising: obtaining conditions of incident light in vicinity of the said vehicle by daylight sensor; determining a current state of engine of the said vehicle; and controlling a state of the headlamp based at least in part on the current state of the engine and the conditions of the incident light, characterized in that the controlling the state of the headlamp comprises: obtaining a wavelength of the incident light; and determining a logarithmic output of the incident

light if the wavelength of the incident light is determined to be between 450 nm and 700 nm.
According to another aspect of the present invention, a system for automatically switching on/off headlamp of two-wheeled vehicles comprising: means for obtaining conditions of incident light in vicinity of the said vehicle by daylight sensor; means for determining a current state of engine of the said vehicle; and means for controlling a state of the headlamp based at least in part on the current state of the engine and the conditions of the incident light, characterized in that the means for controlling the state of the headlamp comprises: means for obtaining a wavelength of the incident light; and means for determining a logarithmic output of the incident light if the wavelength of the incident light is determined to be between 450 nm and 700 nm.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention are set forth with particularity in the appended claims. The invention itself, together with further features and attended advantages, will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only, with reference to the accompanied drawings wherein like reference numerals represent like elements and in which:
Figure 1 illustrates a block diagram of system for automatically switching ON/ OFF headlamp in accordance with an aspect of the present invention.
Figure 2 is a flowchart of a method to enable automatic switching ON/ OFF of the headlamp in accordance with an aspect of the present invention.
Figure 3 illustrates a diagrammatic view of the present invention in accordance with an aspect of the present invention.
Figure 4 illustrates a schematic of electronic control unit in accordance with an embodiment of the present invention.

Figure 5 illustrates a graph showing the performance of a day light sensor in accordance with an aspect of the present invention.
Figure 6 illustrates comparison of different light sources with respect to the day light sensor in accordance with an aspect of the present invention.
Figure 7 illustrates a graphical representation of output signal versus illuminance in accordance with an aspect of the present invention.
Figures 8 illustrate a graphical representation of logarithmic output of day light sensor in accordance with an aspect of the present invention.
Figure 9 illustrates a relationship between maximum detectable light level and load resistance in accordance with an aspect of the present invention.
Figure 10 shows the deviation of the brightness measurements relative to 25°C for the day light sensor at different brightness levels in accordance with an aspect of the present invention.
DETAILED DESCRIPTION
While the invention is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention as defined by the appended claims.
Before describing in detail embodiments it may be observed that the novelty and inventive step that are in accordance with the present invention reside in the method and

system for automatically switching ON/ OFF headlamp in a two-wheeled vehicles accordingly, the drawings are showing only those specific details that are pertinent to understanding the embodiments of the present invention so as pot to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
The terms "comprises", "comprising", or any other variations uiatui, ait intended to cover a non-exclusive inclusion, such that a setup, device that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such setup or device. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
According to one aspect of the present invention, a method of automatically switching on/off headlamp of two-wheeled vehicles, said method comprising: obtaining conditions of incident light in vicinity of the said vehicle; determining a current state of engine of the said vehicle; and controlling a state of the headlamp based at least in part on the current state of the engine and the conditions of the incident light, characterized in that the controlling the state of the headlamp comprises: obtaining a wavelength of the incident light; and determining a logarithmic output of the incident light if the wavelength of the incident light is determined to be between 450 nm and 700 ran.
According to another aspect of the present invention, determining the current state of the engine comprises: turning the headlamp OFF if the state of the engine of the said vehicle is OFF.
According to yet another aspect of the present invention, the logarithmic output of the incident light is determined based on variables Ev1 and EV2 in accordance with the equation log(8E)= log (EVl)-log (EV2) wherein Ev1 is a first value of intensity of the incident light; and EV2 is a second value of intensity of the incident light.

According to still another aspect of the present invention, response to determining the logarithmic output, determining a received output current based on variables Ii and I2 in accordance with the equation 81= I1-I2, wherein I] is a first value of current; and I2 is a second value of current.
According to one aspect of the present invention, controlling the state of the headlamp further comprises: determining whether the wavelength of the incident light is 555 nm; and performing a comparison of the first value of intensity of the incident light with a threshold value of intensity of light.
According to another aspect of the present invention, performing the comparison of the first value of intensity of the incident light with the threshold value comprises: determining an average of at least two samples of incident light if the first value of intensity of the incident light is less than the threshold value; and turning the headlamp of the vehicle ON after a short delay.
According to yet another aspect of the present invention, performing the comparison of the first value of intensity of the incident light with the threshold value comprises: turning the headlamp OFF if the first value of intensity of the incident light is greater than the threshold value after the short delay.
According to still another aspect of the present invention, the method further comprising: determining an upper limit of intensity of the incident light by operating an external load resistance with the daylight sensor; switching OFF the external load resistance in response to detecting a short circuit across the external load resistance; and switching ON the external load resistance after a short delay.
According to one aspect of the present invention, in response to detecting the short circuit across the external load resistance, switching the external load resistance OFF until power resets.

According to another aspect of the present invention, a system for automatically switching on/off headlamp of two-wheeled vehicles comprising: means for obtaining conditions of incident light in vicinity of the said vehicle; means for determining a current state of engine of the said vehicle; and means for controlling a state of the headlamp based at least in part on the current state of the engine and the conditions of the incident light, characterized in that the means for controlling the state of the headlamp comprises: means for obtaining a wavelength of the incident light; and means for determining a logarithmic output of the incident light if the wavelength of the incident light is determined to be between 450 nm and 700 nm.
According to yet another aspect of the present invention, means for determining the current state of the engine comprises means for turning the headlamp OFF if the state of the engine of the said vehicle is OFF.
According to still another aspect of the present invention, means for determining the logarithmic output of the incident light based on variables Ev1 and Ev2 in accordance with the equation log(5E)= log (EVl)-log (EV2), wherein Evi is a first value of intensity of the incident light; and EV2 is a second value of intensity of the incident light.
According to one aspect of the present invention means for determining a received output current in response to means for determining the logarithmic output based on variables Ii and h in accordance with the equation δ1= I1-I2, wherein Ii is a first value of current; and I2 is a second value of current.
According to another aspect of the present invention, means for controlling the state of the headlamp further comprises: means for determining whether the wavelength of the incident light is 555 nm; and means for performing a comparison of the first value of intensity of the incident light with a threshold value of intensity of light.

According to yet another aspect of the present invention, means for performing the comparison of the first value of intensity of the incident light with the threshold value comprises: means for determining an average of at least two samples of incident light if the first value of intensity of the incident light is less than the threshold value; and means for turning the headlamp of the vehicle ON after a short delay.
According to still another aspect of the present invention, means for performing the comparison of the first value of intensity of the incident light with the threshold value comprises: means for turning the headlamp OFF if the first value of intensity of the incident light is greater than the threshold value after the short delay.
According to one aspect of the present invention, the system further comprising: means for determining an upper limit of intensity of the incident light by operating an external load resistance with the daylight sensor; means for switching OFF the external load resistance in response to detecting a short circuit across the external load resistance; and means for switching ON the external load resistance after a short delay.
According to another aspect of the present invention, the system further comprising: means for switching the external load resistance OFF until power resets in response to detecting the short circuit across the external load resistance.
Figure 1 illustrates a block diagram of the automatic headlight ON/OFF control system in accordance with an aspect of the present invention. To overcome the drawbacks faced by the conventional mechanisms, the present invention provides a simple and easy method and system for automatically switching ON/ OFF the headlamp in two-wheeled vehicles. The system for automatically switching ON/ OFF the headlamp comprises of a day light sensor (101) mounted in speedometer console of the vehicle. The day light sensor (101) detects the incident light conditions and gives output to an electronic control circuit (102) i.e. head light control unit. The electronic control unit (102) is located below the headlamp or below seat of the two- wheeled vehicle. Based on the output signal received from the daylight sensor (101), the electronic control unit (102) determines whether to

switch ON or OFF the dipper of headlight of the vehicle after a predetermined delay time. The electronic control unit (102) further comprises of signal conditioning unit (103), logic controller (104) and regulated supply (105). The logic controller (104) of electronic control unit (102) determines whether to switch ON/ OFF the headlamp depending upon the ambient light conditions. The regulated supply (105) is given to the electronic control unit (102) so that the electronic control unit (102) provides regulated power supply (105) to the day light sensor (101). The day light sensor (101) accurately differentiates low brightness level to high brightness level and small changes in those levels. Thus, while selecting the day light sensor (101), all possible light sources are to be taken into account such as street light, HID, sodium vapor lamp, tube lights and vehicle lights etc.
Figure 2 is a flowchart of a method to enable automatic switching ON/ OFF of the headlamp in accordance with an aspect of the present invention. According to one aspect of the present invention, the day light sensor (101) obtains ambient light conditions in vicinity of the vehicle. The current state of engine of the vehicle is checked (201). If the engine is OFF, the headlamp is switched OFF (202). And if the current state of the engine is ON (201), then the wavelength of the incident light is checked. If the wavelength of the incident light is between 450 nm and 700 nm (203), a logarithmic output of the incident light is determined (204) using equation:
log(5E) = log (Evi)-log (Eva). where, Evi is a first value of intensity of the incident light; and Ev2 is a second value of intensity of the incident light. And, if the wavelength of the incident light does not lie between 450 nm and 700 nm, headlamp is switched OFF (202).
Further, a received output current is determined (205) using equation, 51= I1-I2 where, Ii is a first value of current; and I2 is a second value of current. Then, if the wavelength of the incident light is equal to 555 nm (206), a comparison of the first value of intensity of the incident light is performed with a threshold value of intensity of light (207). If the first value of intensity of the incident light is less than the threshold value, an average of at least two samples of incident light is determined and the headlamp is turned ON after a short delay. If the first value of intensity of the incident light is greater than the threshold

value, the headlamp is turned OFF after the short delay. And, if the wavelength of the incident light is not equal to 555 nm (206), the headlamp is switched OFF (202).
According to another aspect of the invention, an upper limit of intensity of the incident light is determined by operating an external load resistance with the daylight sensor (101). First, a current state of the headlamp is checked. If the headlamp is ON (208), then, if the short circuit is detected across the external load resistance (209), the external load resistance is switched OFF and after a short delay; the external load resistance is switched ON. And, if the short circuit is detected at least seven times across the external load resistance, switching the external load resistance OFF until power resets (210).
If the short circuit is not detected across the load resistance (209) then the wavelength of the incident light is checked. If the wavelength of the incident light is between 450 nm and 700 nm (211), a logarithmic output of the incident light is determined (212) if the wavelength of the incident light is determined using equation:
log(δE) = log (Ev1)-log (EV2), where, Ev1 is a first value of intensity of the incident light; and EV2 is a second value of intensity of the incident light.
Further, a received output current is determined (213) using equation, δ1= I1-I2 where, I1 is a first value of current; and I2 is a second value of current. Then, if the wavelength of the incident light is equal to 555 nm (214), a comparison of the first value of intensity of the incident light is performed with a threshold value of intensity of light (215). If the first value of intensity of the incident light is less than the threshold value, an average of at least two samples of incident light is determined and the headlamp is turned ON after a short delay. If the first value of intensity of the incident light is greater than the threshold value, the headlamp is turned OFF after the short delay.
Figure 3 illustrates a diagrammatic view of the present invention in accordance with an aspect of the present invention. Both manual and auto mode operation of the head lamp is shown in fig. 3. For automatic operation, the day light sensor (101) is used with

electronic control unit (102). A power source which can be a battery of 12V DC supply can be given to the electronic control unit (102) so that the electronic control unit (102) provides regulated power supply (105) (e.g. a 5V DC) to the day light sensor (101). The day light sensor (101) detects ambient light conditions and gives output to the electronic control unit (102). The electronic control unit (102) determines to switch ON or OFF the head lamp of the vehicle. The electronic control unit (102) always switches ON the headlamp in lower dipper position due to safety reasons and also glows the taillight and speedo illumination of speedometer simultaneously.
Figure 4 illustrates a schematic view of a circuit for an electronic control unit in accordance with an aspect of the present invention.
According to one embodiment of the present invention, the output signal in the form of current from the daylight sensor (101) is converted into voltage and is fed as input to the electronic control unit (102). The output current from the day light sensor (101) is directly proportional to the amount of incident light. The electronic control unit (102) comprises of micro-controller Ul, Transistor 1, Transistor 2, relay, resistors and capacitors. Micro-controller Ul is used for making decision to switch ON/OFF the headlamp through transistor 1 and relay. Further, the micro-controller senses engine ON condition through R8, D3, R7, D2, R9 and transistor 2 and senses ambient light conditions in the vicinity of the vehicle with the help of the daylight sensor (101). The headlamp gets switched ON only in dark condition provided engine is ON. Engine ON position is sensed by the transistor 2 through an arrangement of components R8, D5, R7, D2, R9, and R6. The transistor 2 then feeds pulses to the micro-controller when it gets an AC-input. When dark condition is sensed, the micro-controller activates transistor 1 through resistor R3. The transistor 1 then makes relay ON which then switches the headlamp ON. In day condition the micro-controller switches transistor 1 OFF through resistor R3 after a predetermined delay time, which in turn then makes relay OFF and switches the headlamp to OFF position.

Figure 5 illustrates a graph showing the performance of a day light sensor in accordance with an embodiment of the present invention. In the present invention, sensors are used to configure and adjust to the incident light conditions as perceived by the humans. The sensors are designed to detect brightness in the same way as human eyes do. To achieve this, the sensor needs to have a spectral sensitivity which is similar to that of human eyes. As shown in fig. 5, a standard Si-detector has its maximum sensitivity in the IR range, which is invisible to human eyes. Lamps however do emit light in the IR range, which is invisible to human eyes, which then leads a standard Si-detector to see high brightness, whereas, in fact it is not bright to human eyes. This match with the human eye characteristics is the most important parameter of a day light sensor of the present invention.
Figure 6 illustrates comparison of different light sources with respect to the day light sensor in accordance with and aspect of the. present invention. All light sources appear equally bright to human eyes. All signals as shown in fig. 6 are normalized to standard light (2856K), which is a general point of reference for the day light sensor of the present invention. A light bulb, for instance emit a high portion of IR light, which is fully detected by the standard Si-detector, but is not seen by the human eye. Fluorescent lamps, on the other hand, do not emit much IR light. Hence, the signals yield by the standard Si detectors is much higher for light bulbs than they are for fluorescent lamp, even though both lamps appear equally bright to the human eye.
Further, the deviation of the brightness measurement for the different light sources can directly be derived from figure 6. Compared to human eye, the standard Si-detector signal is 3% (high) in case of a light bulb and over 90% (too low) for a fluorescent lamp. However, for the day light sensor, respective values for both light bulb and fluorescent lamp are approximately 1% only. Thus, when selecting a sensor to sense the incident light conditions in the vicinity of the vehicle, all possible light sources have to be taken into account.

Figure 7 illustrates a graphical representation of output signal versus illuminance in accordance with an aspect of the present invention. In order to represent the wide dynamic range of incident light illuminance Ey (lux) correctly, the day light sensor of the present invention is equipped with an analog logarithmic current output. The output current Iout [uA] of the day light sensor versus illuminance Ev [lx]I0Ut = S *log(Ev/E0) with E0 = llx, Sensitivity S = lOuA/dec is shown in fig. 7. For brightness measurements, a good relative resolution over the entire brightness range is important. In other words, when measuring low brightness levels, small changes in those levels need to be detected, whereas, when high brightness levels are measured, only relatively large variations are of interest (a change from 100 lx to 200 lx is considerable, whereas, the step from lOOOOlx to 10200 lx is negligible).
For linear output detectors like photo transistors or photo diodes, brightness changes AEv result in changes ∆Iout of the output current (an increase of the illuminance by a factor 2 results in an increase of the output current by a factor 2 for linear output detectors), which are proportional to AEv. To resolve small variations in low illumination levels it is necessary to measure in small current steps. At high brightness levels, however, it makes little sense to collect data with such fine absolute resolution.
Figures 8 A and 8B illustrate a graphical representation of logarithmic output of day light sensor in accordance with an aspect of the present invention. According to one aspect of the present invention, logarithmic output of the day light sensor converts equal ratios of detected illuminance levels Ev1, Ev2 into output current levels Iv1 and Iv2 of equal steps. The following example illustrates the said effect. In many applications, the output signals are processed by an A/D converter. However, in the following example, an 8bit converter is used.
A linear output photo detector detects a maximum of lOOklx. Hence, 256 different values are available to resolve the lOOklx. Because of the linear relationship between output current and illuminance, the 256 values are equally distributed over the entire detection range, which yields a fixed value of 390Ix/bit. This setting cannot resolve light levels

below l000lx with sufficient accuracy. Therefore, the operating range is changed to Olx to lOOOlx by switching to a different resistor value (for example, a typical value of 0.4mA photocurrent at lklx, a 6.9k£3 resistor yields 2.8V voltage drop at the A/D converter. To enhance the detection range to lOOklx, the 2.8V must resemble lOOklx. And the resistor needs to be decreased to 69H in order to achieve a resolution of 3.91x/bit for levels below lOOOlx. The relative accuracy of the measurement is defined by the bit size and varies depending on the operating range.
However, in the case of a logarithmic output, the 256 bits are not evenly distributed over the detection range, but at a fixed ratio with the absolute detected value. Equal ratios of detected illuminance levels are converted into output current levels of equal steps as shown in fig. 5. The relative accuracy of the measurement in this case is a constant value over the entire ilumi nance range.
As shown in figure 8B, a linear photo detector needs to be operated with different resistors to change between different detection ranges, which is not necessary for the logarithmic output signal device. In the above example, the day light sensor can directly be connected to an ADC input via an external load resistor.
Figure 9 illustrates a relationship between maximum detectable light level and load resistance in accordance with an aspect of the present invention. According to one aspect of the present invention, the day light sensor is operated with an external load resistance RL. In such case, the upper detection limit of the day light sensor depends on the resistor value of RL. The load resistance RL does not directly determine the maximum detection level, but determine the output voltage of the day light sensor, which is limited by the supply voltage Vcc. At high illuminance levels the output current Iout is high and the load resistance must be reduced in order to stay below Vcc (Vout 5VCC = Iout * RL)- For 2.5V supply voltage, the detection limit for a 56kQ resistor is ~9klx. To increase this level, a lower resistor value is necessary. With 47kQ up to 60klx can be detected. For higher Vcc, the reachable detection limit increases with the same resistor values.

Figure 10 illustrates the deviation of the brightness measurements relative to 25°C for the day light sensor at different brightness levels in accordance with an aspect of the present invention. The temperature coefficient of the day light sensor is not a constant value; however, it depends on the illuminance range under which the sensor is operated. Corresponding data for various photo transistors and photo diodes is shown in fig. 10. In comparison to a phototransistor, the day light sensor of the present invention yields a better accuracy at all brightness levels. Above lOOlx, the temperature behavior of the day light sensor is comparable to that of a photodiode. At lOlx and high temperatures, greater deviations than those of photodiodes have to be taken into account.
ADVANTAGES OF THE INVENTION
The present invention has following advantages:
i) The present invention has a faster response time.
ii) The sensor used in the present invention has spectral sensitivity that matches with
the human eyes perfectly iii) The present invention has a high linearity and error free light reading. iv) The present invention provides an auto high-low beam changeover. v) The present invention protects and saves battery and enhanced the life span of the
battery. vi) The present invention reduces the chances of short circuit.
While the particular preferred embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the' teachings of the invention. It is therefore contemplates that the present invention cover any and all modifications, variations or equivalents that fall within the scope of the basic underlying principles disclosed above and claimed herein

We claim:
1. A method of automatically switching on/off headlamp in two-wheeled vehicles,
said method comprising:
obtaining conditions of incident light in vicinity of the said vehicle;
determining a current state of engine of the said vehicle; and
controlling a state of the headlamp based at least in part on the current state of the engine and the conditions of the incident light,
characterized in that the controlling the state of the headlamp comprises:
obtaining a wavelength of the incident light; and
determining a logarithmic output of the incident - light if the wavelength of the incident light is determined to be between 450 nm and 700 nm.
2. The method as claimed in claim 1, wherein determining the current state of the
engine comprises:
turning the headlamp OFF if the state of the engine of the said vehicle is OFF.
3. The method as claimed in claim 1, wherein the logarithmic output of the incident
light is determined based on variables Evi and R,2 in accordance with the equation
log(5E)= log (EVl)-log (EV2)
wherein Ev1 is a first value of intensity of the incident light; and Ev2 is a second value of intensity of the incident light.
4. The method as claimed in claim 3, wherein in response to determining the
logarithmic output, determining a received output current based on variables I1 and I2 in
accordance with the equation 51= I1-I2,
wherein I1 is a first value of current; and I2 is a second value of current.
5. The method as claimed in claim 1, wherein controlling the state of the headlamp
further comprises:
determining whether the wavelength of the incident light is 555 nm; and

performing a comparison of the first value of intensity of the incident light with a threshold value of intensity of light.
6. The method as claimed in claim 5, wherein performing the comparison of the first
value of intensity of the incident light with the threshold value comprises:
determining an average of at least two samples of incident light if the first value of intensity of the incident light is less than the threshold value; and turning the headlamp of the vehicle ON after a short delay.
7. The method as claimed in claim 5, wherein performing the comparison of the first
value of intensity of the incident light with the threshold value comprises:
turning the headlamp OFF if the first value of intensity of the incident light is greater than the threshold value after the short delay.
8. The method as claimed in claim 1, further comprising,
determining an upper limit of intensity of the incident light by operating an external load resistance with the daylight sensor;
switching OFF the external load resistance in response to detecting a short circuit across the external load resistance; and
switching ON the external load resistance after a short delay.
9. The method as claimed in claim 8, wherein in response to detecting the short circuit across the external load resistance, switching the external load resistance OFF until power resets.
10. A system for automatically switching on/off headlamp in two-wheeled vehicles comprising:
means for obtaining conditions of incident light in vicinity of the said vehicle;
means for determining a current state of engine of the said vehicle; and
means for controlling a state of the headlamp based at least in part on the current state of the engine and the conditions of the incident light,
characterized in that the means for controlling the state of the headlamp comprises:

means for obtaining a wavelength of the incident light; and means for determining a logarithmic output of the incident light if the wavelength of the incident light is determined to be between 450 nm and 700 nm.
11. The system as claimed in claim 10, wherein means for determining the current
state of the engine comprises:
means for turning the headlamp OFF if the state of the engine of the said vehicle is OFF.
12. The system as claimed in claim 10, further comprising: means for determining tne
logarithmic output of the incident light based on variables Ev1 and EV2 in accordance with
the equation Iog(5E)= log (EVl)-log (EV2)
wherein Ev1 is a first value of intensity of the incident light; and Ev2 is a second value of intensity of the incident light.
13. The system as claimed in claim 12, further comprising: means for determining a
received output current in response to means for determining the logarithmic output
based on variables lx and I2 in accordance with the equation 51= I1-I2
wherein I| is a first value of current; and h is a second value of current.
14. The system as claimed in claim 10, wherein means for controlling the state of the
headlamp further comprises:
means for determining whether the wavelength of the incident light is 555 nm; and
means for performing a comparison of the first value of intensity of the incident light with a threshold value of intensity of light.
15. The system as claimed in claim 14, wherein means for performing the comparison
of the first value of intensity of the incident light with the threshold value comprises:
means for determining an average of at least two samples of incident light if the first value of intensity of the incident light is less than the threshold value; and means for turning the headlamp of the vehicle ON after a short delay.

16. The system as claimed in claim 14, wherein means for performing the comparison
of the first value of intensity of the incident light with the threshold value comprises:
means for turning the headlamp OFF if the first value of intensity of the incident light is greater than the threshold value after the short delay.
17. The system as claimed in claim 10, further comprising,
means for determining an upper limit of intensity of the incident light by operating an external load resistance with the daylight sensor;
means for switching OFF the external load resistance in response to detecting a short circuit across the external load resistance; and
means for switching ON the external load resistance after a short delay.
18. The system as claimed in claim 17, further comprising: means for switching the external load resistance OFF until power resets in response to detecting the short circuit across the external load resistance.
19. A method for automatically switching on/off headlamp in two-wheeled vehicles substantially as herein described with reference to the accompanying drawings.
20. A system for automatically switching on/off headlamp in two-wheeled vehicles substantially as herein described with reference to the accompanying drawings.