DE3808965A1 - Combined device for warning of the onset of dusk and monitoring lights, in particular for vehicles - Google Patents

Abstract

The invention relates to a combined device for warning of the onset of dusk and monitoring lights for vehicles and systems of all kinds which are equipped with light sources which have to be switched on as the ambient brightness decreases. The warning device is capable of fulfilling the following warning functions (warning = triggering of a warning signal) in a particularly simple manner after being easily retrofitted into already existing systems: 1. Warning when the ambient light has dropped below a critical value (which is adjustable) and the light source (the vehicle's or system's own light, boundary lights, position lights or headlights) have not been switched on. 2. Warning when the light source (which may be operated electrically, chemically or by means of other energy sources) itself is not emitting adequate light. 3. Warning when the translucency of the protective glass has decreased (e.g. in the case of a soiled headlight glass) or if e.g. the reflective capacity of the reflector of the light source has decreased greatly. 4. Optional additional warning if an electric light system is switched on whilst another electric system, e.g. the charging device for the battery (engine) is switched off.

Description

The invention relates to a safety-related Warning device for vehicles and systems of all kinds, such as B. Light orientation systems (light buoys etc.) which are equipped with light sources, which at decreasing ambient brightness can be switched on should.

The warning device is particularly simple and with existing systems in following functions can be easily retrofitted to fulfill:

• 1. Warning if the ambient lighting is below dropped an (adjustable) critical value and the light source (self-illumination, Side lights, position lights or Headlight) was not switched on.
• 2. Warning if the light source (be it electrical, operated chemically or by other energy sources) does not emit enough light itself.
• 3. Warning when the light transmittance of the lamp cover has decreased (e.g. with dirty Headlight lens) or if e.g. B. the reflectivity of the reflector the light source has decreased significantly.
• 4. Optionally, additional warning if an electrical Lighting system is on while another electrical system, e.g. B. the charger for the Accumulator (motor) is switched off.

There are a number of facilities and suggestions to facilities that each one of these warning functions or less than the number of these warning functions specified here fulfill.

So is from the published documents DT 25 14 611 A1 or DE 27 05 574 A1 or DE 26 37 287 A1 of the German Patent Office a device to avoid driving without proper outside lighting with a light sensor known, which although the warning functions 1st and 4th partially cover, but not 2nd and 3rd  

Other facilities, e.g. B. according to the published documents DT 26 02 702 A1 or DE 27 41 685 A1 or DE 35 36 626 A1 of the German Patent Office describe facilities that the function of the lighting device of vehicles sometimes also monitor with photo detectors or photocells (= Warning function 2.) - but not the warning functions 1. and 3. take over.

In addition, a number of simple warning devices are included Road vehicles in use, which are a warning signal release when the engine or the main switch is switched off and the lighting device is still switched on, especially an uncontrolled final charge of the car battery is avoided (= warning function 4.).

However, the novel device described here is in able for security in a very simple way Road traffic very important warning functions 1st, 2nd and 3rd and moreover, those that are particularly ready for use important warning function of a motor vehicle 4. simultaneously in a single unit, which can also be easily retrofitted to fulfill.

Many particularly serious accidents come from that when dusk falls, vehicles (especially if they have a dark or inconspicuous color) without light drive and so easily z. B. especially with critical Overtaking by other road users be overlooked.

The driver who turns on the light too late subject to often psychologically understandable but nevertheless possibly very fatal misunderstanding: His eyes are on the slowly beginning dawn used; he still sees the road well, sees the road well other road users who already have the vehicle lighting turned on - and assumes that he is seen by the others as well.

It is not uncommon for such a driver to have to be conspicuous Signs of other road users that almost hit him would have fatally overlooked his Mistake to be made aware.

Also, at night, when starting off, one is illuminated Street parking vehicle often forgotten for the same reason to switch on the vehicle lighting.  

Regardless, similarly dangerous situations can occur arise when there is only one light on the vehicle, e.g. B. the left headlight fails - what the driver usually also without a special warning device noticed.

Another often overlooked source of danger can be from heavily soiled lamps - or headlight protection glasses, or translucent plastic parts or become deaf Reflectors.

Even if the vehicle is heavily soiled, so that, for example, the light output drops to a third, still clearly recognized, but there is a risk that z. B. the removal of such a vehicle from habituation of vehicles with normal lighting assessed as too large becomes.

A facility that uses these warning functions as much as possible simple but reliable in practice, and is also easy to retrofit would be safety-related very desirable.

The warning device described here can perform these tasks satisfy.

The essential parts of the unit and their arrangement are summarized in Fig. 1:
An electronic circuit ( 1 ) with warning device ( 4 ) is connected via a line ( 3 ) to a photodetector ( 2 ) which, through a small opening ( 10 ) through the lamp outer housing ( 9 ) and through e.g. B. a small opening in the reflector ( 8 ) near the socket of the light source ( 6 ) is positioned in the interior of the lamp to be monitored, that it is simultaneously (in certain proportions) of the light from the light source ( 6 ) and through the protective pane ( 7 ) and is illuminated by the reflector ( 8 ) from the external ambient light.

The circuit ( 1 ) z. B. in the engine compartment of a car near the electrical terminal box, and connected to the alarm device ( 4 ) in the driver's interior via a two-wire low-voltage cable.

Circuit ( 1 ) and alarm device ( 4 ) can also be combined in one housing.

Fig. 2 describes a simple example of the electronic circuit.

Connection ( 11 ) should be placed on vehicle ground;
Connection ( 12 ) should be connected to a terminal that has a positive potential when the main switch is switched on or when the engine is running (automotive terminal 61 ).
Connection ( 13 ) should be connected to a terminal that carries positive potential when the lighting is switched on.
If the warning function 4. is not desired, connection ( 13 ) does not need to be connected.

The warning threshold is essentially determined by the sensitivity of the photodetector ( 14 ) and the adjustable resistance ( 15 ).

As a photodetector z. B. CdS photo resistors or Si photodiodes or Si phototransistors are suitable. The photodetector should be in the visible wavelength range be sensitive.

Possibly the detector sensitivity can be adjusted by suitable Filter varnishes are adapted to the eye sensitivity curve, this prevents the overvaluation of incandescent light e.g. B. with Si detectors (by their IR sensitivity).

The capacitor ( 17 ) averages rapid light fluctuations in the time range from z. B. 10 s (practically arbitrary).

The transistors ( 18 ) and ( 19 ) work as current amplifiers with very low photo currents, the emitter follower chain can be expanded by further transistors, or field effect transistors can also be used.

The components ( 25 ) and ( 26 ) represent the optical and the acoustic warning signal transmitter.

You can easily through a luminescent diode (with series resistor) and a piezo buzzer can be realized.  

Function of the arrangement according to FIGS. 1 and 2

If sufficient ambient light falls through the protective pane and over the reflector - or sufficient light from the light source - onto the photodetector, the variable resistor ( 15 ) should be set so that the capacitor remains practically discharged and the warning signal transmitter ( 25 ), ( 26 ) without Stay current.

Only below a threshold of the ambient lighting that can be set with ( 15 ) and a light source ( 6 ) that is not switched on or does not function is the capacitor charged to such an extent that the warning signal transmitters are triggered.

In this circuit, it is particularly easy in rainy weather, when the windshield wiper is switched on, to shift the warning threshold towards higher ambient lighting values, by means of a possibly adjustable resistor ( 82 ), which is connected to a connection of the windshield wiper system via terminal ( 83 ) which has positive electrical potential when it is switched on. In e.g. B. the publication DT 25 14 611 A1, the displacement of the light switch-on threshold depending on the wiper operation has already been proposed in a similar manner.

If the lamp protection screen ( 7 ) is very dirty or the reflector corrodes, the alarm threshold shifts noticeably to greater ambient brightness - or in the case of typical cloudiness and a certain season, earlier times of the day.

This is a clear indication that the Lighting fixture is not OK - regardless of the Function of the light source itself.

With a second light threshold alarm, the z. B. in the area of pollution from wipers cleared windshield can also Ambient lighting can be determined objectively, and so from the Sequence of warning operations for both light threshold signals even an objective measure of lighting pollution can be obtained (cf. claim 13).  

A simple exemplary embodiment of such a circuit is shown in FIG. 7.

Here the light detector ( 70 ) is in the ambient light influence area (also scattered light) of a dirt-free protective pane and can be adjusted with the adjuster ( 71 ) so that the second piezo buzzer - or possibly the second optical warning device ( 72 ) only responds when the the first dark threshold circuit (with the light detector ( 14 ) and the adjuster ( 15 )) responds much earlier than the second dark threshold circuit with ( 70 ) and ( 71 ).

In Fig. 3 it is also shown how the light detector ( 2 ) in the lamp housing ( 5 ) z. B. either according to Fig. 3a with a photodetector component ( 14 ) with (possibly but not necessarily shielded) electrical line ( 31 ) to the circuit ( 1 ) or advantageously through the end of an optical fiber or an optical fiber bundle ( 32 ) which captures the light from where it can be implemented via the fiber ( 32 ) to a light detector ( 14 ) in the circuit unit ( 1 ).

Several lamps can be monitored simultaneously by equipping each lamp ( 5 ) to be monitored with a light detector ( 2 ) and simply connecting the associated detector components ( 14 ) electrically in series, as shown in FIG. 4 using the example of two detectors ( 14 ), here designated ( 41 ) and ( 43 ).

In the case of lamps with different ambient light incidence, the sensitivity S of the light detectors, e.g. B. ( 31 ), ( 42 ) ,. . . be adapted to it according to claims 3 to 5.

The light detectors z. B. ( 41 ) and ( 42 ) can, however, as the circuit in Fig. 5 shows, each with its own input stage with sensitivity adjusters ( 44 ), ( 46 ) ,. . . e.g. B. with its own input transistors ( 49 ), ( 50 ),. . . have, whose signal is then used in a logic OR circuit (simply here, for example, by interconnecting the emitter diodes of the transistors) to trigger the dark warning signal.

This possibility is set out in claim 6.  

Fig. 6 shows again a detailed circuit example in which the integrated circuit for the interruption of the alarm signal.

The time constant of components ( 63 ) and ( 64 ) determines the length of the warning signal (e.g. 1 s) and the time constant of components ( 66 ) and ( 67 ) + ( 15 ) essentially determines the time of the warning signal pause (e.g. B. 10 ... 100 s).

Suggestions for the values of the individual components of all Figures are included in the following table.  

List of components shown in the figures:

(Examples without limitation of generality

Practical embodiment:

A simple but effective form of the device according to the invention is, for example, the circuit according to FIG. 2 built on a small, approximately 3 cm × 3 cm large circuit board with approximately 1 m to 2 m optical fiber cable, a two-wire line (2 × 0.2 mm ↑ 2 cross section is sufficient) for the connection of a piezo signal transmitter (12 V, 2 ... 10 mA), and the four vehicle connections ( 11 ), ( 12 ), and possibly ( 13 ) and ( 83 ) housed in a small one Plastic case with approx. 4 cm × 4 cm × 2 cm.

The electrical lines and the optical fiber can from this plastic housing, the circuit may also be partially or entirely with z. B. potted resin can be simply loosely led out and the electrical cables at the ends z. B. with cable lugs or eyelets.

For retrofitting all warning functions and the Monitoring the left headlight in a motor vehicle, e.g. B. a car is then the following simple assembly process required:

• - The plastic box ( 1 ) with the circuit is fastened with a simple holding device (e.g. cable tie) in the engine compartment near the fuse box.
• - The optical fiber cable is through the headlight lamp housing (e.g. through the through opening of the electrical supply lines - or through your own small hole to be drilled with a diameter of approx. 3 mm) smuggled and the light receiving end through a Opening or crack of the reflector or one of the Incandescent lamp holders (high / low beam or position lamp) inserted about 1 cm deep.
• - The connecting cable ( 11 ) is connected to the vehicle earth, the cable ( 12 ) is connected to the operating potential at the main switch (e.g. vehicle terminal 61 ).

The device already fulfills the warning functions 1 to 3.

For further functions (warning when the engine is off and the light is on or the dark warning threshold is increased when it rains), the cables ( 13 ) and ( 83 ) are connected to the light switch and the wiper motor.

• - The connection cable to the piezo warning signal transmitter is in the Pulled the driver's compartment and connected the Piezowarner there.
• - finished!

Such an institution was created by the authors Tried and tested for a long time fully satisfactory.

Because the illuminance between full daylight and dusk decreases from approx. 10,000 lux to approx. 100 lux, does not prepare the setting of the warning threshold Problem - and could in the interest of road safety also to a certain standard size of the ambient illuminance (which according to claim 26 also by a Calibration auxiliary light source at a certain distance from the cleaned lamp can be realized) fixed will.

Because of the validity of Weber-Fechner's law that the physiological sensations of sensations in humans rather correspond to the logarithmic values of the corresponding physical quantities (here the illuminance), these large differences in brightness of almost a factor of 100 will not be noticed.

The cost of this embodiment was from Material value under about 15 DM. The manufacturing costs for Larger quantities should be kept well below DM 20 can be.

That such a device (e.g. as a retrofit kit) still is not offered on the market also speaks for the novelty and inventiveness of proposed facility.

Claims (28)

1. Warning device via the illumination state of vehicles or light orientation equipment (Beacon, etc.) which depends on the ambient lighting and the operation state (z. B. driving or parking or light switch on or off, etc.) of the equipment emits a warning signal or automatically triggers circuits, characterized in that a light radiation detector ( 2 ) is arranged between the light source and the protective device (e.g. in the space between the incandescent lamp with reflector and protective glass in the case of a headlight) in such a way that it both reduces the external lighting by the light transmission factor of the protective device (protective glass) or / and also reduced by the reflection factor of the reflector and the radiation from its own light source, and thus combines at least three different monitoring functions in a very simple and easily retrofittable device.
These functions are:

• - Warning or switching signal if the ambient lighting drops below a certain (possibly adjustable) value
• - Switch off the warning signal when the self-lighting is switched on
• - Warning if self-lighting does not work
• - Warning (at least indirectly due to changed dark threshold of the ambient lighting) if the light source protection device (headlight protection glass) and / or the reflector have become dirty or cloudy
• - Warning if self-lighting is switched on but the main switch (motor) is switched off.

2. Device according to claim 1, characterized in that instead of the light radiation detector itself the light-receiving end ( 33 ) of an optical fiber ( 32 ) or an optical fiber bundle occurs and the light introduced there is guided via this optical fiber cable to a radiation detector which is located at a suitable point, for . B. on a circuit board of the warning device ( 1 ). 3. Device according to claim 1 or 2, characterized in that several lights ( 5 ) are monitored simultaneously by containing a light detector ( 2 ), which are electrically connected in series, so that each light detector in the measure of the reverse product of ambient light radiation and detector sensitivity Triggering of the light switch-on signal contributes and a sustained warning signal after switching on the lighting indicates at least one non-illuminating monitored light source. 4. Device according to at least claim 3, characterized in that the sensitivity of the light detectors connected in series in the inverse ratio to the contribution of light radiation from the ambient lighting when the protective screen ( 7 ) and the normally reflecting reflector ( 8 ) are selected so that the transmission of the protective screen ( 7 ) or the reflectivity of the reflector ( 8 ) of each of the monitored light sources is evaluated uniformly. 5. Device according to at least claim 3, characterized in that the sensitivity of the light detectors ( 2 ) to the transmission and reflection conditions in the respective monitored lights ( 5 ) by an adjustable aperture at the light entry of the light detectors, in the simplest case by covering with opaque paint , is adjusted. 6. Device according to claim 1 and 3 and possibly 2, characterized in that the light detectors of the lights to be monitored are individually connected to the warning device ( 1 ) and are connected there to input stages with individually adjustable sensitivity, the output of which is already darkened by a light detector the presettable minimum lighting value emits a signal (logical OR circuit with respect to the dark warning signal) which is then converted into a warning signal in the following switching elements of the warning device ( 1 ). (e.g. Fig. 5). 7. Device according to one of the preceding claims, characterized by that the warning signal is an acoustically perceptible continuous tone or an interrupted tone or an optically perceptible Can be steady or a flashing light. 8. Device according to one of the preceding claims, characterized, that the warning signal generator may have a piezo buzzer internally connected breaker. 9. Device according to one of the preceding claims, characterized in that the warning signal transmitter is a luminescent diode ( 25 ) with ballast resistor. 10. Device according to one of the preceding claims, characterized, that both an optical and a possibly Acoustic warning signal can be switched off. 11. Device according to one of the preceding claims, characterized in that the acoustic or / and optical warning signal generator is connected by means of three diodes ( 22 ), ( 23 ), ( 24 ) so that warning signal is emitted both when the illuminance is at least one detector ( 2 ) drops below a certain value, as well as when the supply voltage ( 12 ) of the circuit ( 1 ) is switched off (e.g. ignition voltage or motor) while a second line ( 13 ) still carries voltage which, for. B. is connected to the terminals of the vehicle lighting. 12. Device according to one of the preceding claims, characterized in that the circuit ( 1 ) is designed so that the potential line ( 13 ) need not be connected without the warning function when the lighting is switched off and the supply voltage ( 12 ) is switched off the remaining warning functions are restricted. 13. Device according to one of the preceding claims, characterized in that a second dark threshold circuit whose light detector ( 70 ) receives the ambient light as undisturbed by dirt-sensitive filters or reflectors with the first dark threshold circuit with the light detector ( 14 ) in the light to be monitored ( 5 ) so is switched so that an (acoustic or / and optical) warning device ( 72 ) responds when the first dark threshold circuit responds (i.e. the light power received in ( 14 ) is below the threshold value that can be adjusted with an adjusting device ( 15 )) while the second dark threshold circuit is still operating does not respond (ie if the light output received in ( 70 ) is still above the threshold value that can be set with an adjusting device ( 71 )). With a suitable adjustment of the threshold values with ( 15 ) or ( 71 ), the warning device ( 72 ) emits an additional warning signal from a certain degree of contamination of the protective pane ( 7 ) of the lamp ( 5 ) corresponding to the decreasing light permeability (cf. FIG. 7 ). 14. The device according to at least claim 13, characterized in that the illuminance of the two light detectors ( 14 ) and ( 70 ) corresponding currents of a quotient circuit (electromechanical or electronic analog or digital) and their output signal, which is a measure regardless of the ambient illuminance for the light transmittance of the protective pane ( 7 ) or possibly also the reflectivity of the reflector ( 8 ), is directly displayed (analog or digital) or is supplied to a threshold circuit which triggers a warning signal from a certain adjustable light ratio value. 15. The device according to at least claim 13 or 14, characterized in that the second light detector ( 70 ) in the interior z. B. the vehicle or the light orientation device is mounted so that it receives the ambient light as possible from the same solid angle range as the first light detector ( 14 ); however, if possible, through viewing windows kept free of dirt with wipers. 16. Device according to one of the preceding claims, characterized, that the warning devices with a through Appropriate design of the circuit delayed on the light signals on the light detector or on the Light detectors respond to responding at only brief changes in ambient light to suppress. 17. The device according to at least claim 16, characterized in that the time delay is achieved with a capacitor ( 17 ), the one hand via resistors z. B. ( 15 ), ( 16 ), ( 74 ) and charged via the electrical current of the light detector z. B. ( 14 ), ( 70 ) is discharged, the charging and discharging time constants being deliberately and sensibly selected differently, e.g. B. so that the circuit responds either faster to brighter or darker light periods. 18. Device according to one of the preceding claims, characterized in that the threshold circuits are additionally stabilized against fluctuations in the vehicle electrical system with resistors ( 61 ), capacitors ( 62 ) and possibly Zener diodes ( 69 ). 19. Device according to one of the preceding claims, characterized in that the photodetector ( 14 ) or ( 70 ) is a photoresistor or a photodiode operated in the reverse direction or a phototransistor and in particular that its spectral sensitivity - possibly with color filters - to the spectral sensitivity of the adapted to the human eye. 20. Device according to one of the preceding claims, characterized in that the currents of the photodetectors with transistors in Darlington circuit ( 18 ), ( 19 ) in possibly more than two stages are successively amplified so that the optical or acoustic warning devices ( 25 ), ( 26 ) can be switched on electronically immediately. 21. The device according to at least claim 20, characterized in that a field effect transistor can be used instead of at least the first transistor ( 19 ). 22. The device according to at least claim 13, characterized in that the dark threshold detector ( 70 ), which is not arranged in the radiation region of the lights to be monitored, automatically switches on the light sources via an electronic or electromechanical relay. 23. Device according to one of the preceding claims, characterized in that the electrical or optical fiber line ( 3 ) of the light detector ( 2 ) through a special small bore ( 10 ) with cable grommet or also through the implementation ( 80 ) of the supply lines of the light source ins Lamp housing ( 9 ) is guided. 24. Device according to one of the preceding claims, characterized in that the warning threshold is raised to a higher ambient illuminance with a simple, possibly adjustable resistor ( 82 ) when the wiper motor is switched on, the positive switching pole of which is connected to the terminal ( 83 ) of the circuit ( 1 ) is connected ( Fig. 2). 25. Device according to one of the preceding claims, characterized in that the setting resistors ( 15 ), ( 44 ), ( 46 ), ( 71 ), ( 82 ) and ( 64 ) to simplify the circuit and to unify the dark threshold values at least partially as Fixed resistors are executed. 26. Device according to one of the preceding claims, characterized in that the twilight warning threshold is set as uniformly as possible to a certain ambient lighting limit, and that the warning threshold setting for a certain photodetector and a certain degree of transmission of the lamp protection screen in the device ( 1 ) is fixed. 27. Device according to one of the preceding claims, characterized, that a calibration light source which in front of the lamp with the Light detector at a fixed distance and shaded by the Ambient light is brought as an aid to uniform Adjustment of the twilight warning threshold is used.